Content uploaded by Karl-Fredrik Nilsson
Author content
All content in this area was uploaded by Karl-Fredrik Nilsson on Oct 23, 2021
Content may be subject to copyright.
JRC REFERENCE REPORTS
Geological Disposal of Radioactive Waste:
Moving Towards Implementation
W.E. Falck and K.-F. Nilsson
2009
Report EUR 23925 EN
The mission of the JRC-IE is to provide support to Community policies related to both nuclear and non-nuclear energy
in order to ensure sustainable, secure and efcient energy production, distribution and use.
European Commission
Joint Research Centre
Institute for Energy
Contact information
Address: P.O. Box 2 • NL-1755 ZG Petten • The Netherlands
E-mail: wefalck@wefalck.eu
Tel.: +31 224 56 54 20 Fax: +31 224 56 56 41
http://ie.jrc.ec.europa.eu/
http://www.jrc.ec.europa.eu/
This publication is a Reference Report by the Joint Research Centre
of the European Commission.
Legal Notice
Neither the European Commission nor any person acting on behalf of the Commission
is responsible for the use which might be made of this publication.
The use of trademarks in this publication does not constitute an endorsement by the European Commission.
The views expressed in this publication are the sole responsibility of the author(s)
and do not necessarily reect the views of the European Commission.
Europe Direct is a service to help you nd answers to your questions about the European Union
Freephone number (*): 00 800 6 7 8 9 10 11
(*) Certain mobile telephone operators do not allow access to 00 800 numbers or these calls may be billed.
A great deal of additional information on the European Union is available on the Internet.
It can be accessed through the Europa server http://europa.eu/.
JRC 45385
EUR 23925 EN
ISBN 978-92-79-12697-0
ISSN 1018-5593
DOI 10.2790/12387
Luxembourg: Ofce for Ofcial Publications of the European Communities
© European Communities, 2009
Reproduction is authorised provided the source is acknowledged.
Printed in the Netherlands
Objectives 8
Paradigm 8
Currentstatusofworksupportingthesafetycase 9
Topicalareasofconcern 10
Overview 10
Wasteinventory 10
Wasteforms 11
Wastecontainers 11
Bufferandbackllmaterials 12
Hostrocks 13
Processesaffectingradionuclidebehaviour 16
Gasgenerationandmulti-phaseowprocesses 20
Interactionbetweenrepositorycomponents 20
Regionalgeologicalsetting 21
Selectionstrategies 22
Humanintrusionriskasacriterion 23
Fundamentalobservations 23
Policymakingandradiationprotection 24
Differingneedsofstakeholders 24
Enablingregulators 25
Regulatorygapsandinconsistencies 25
Towardsacommonunderstanding 26
Table of contents
Conceptualoverview 27
Simplicationissues 29
Upscalingissues 29
Theissueoftimescales 30
Processrelevance 30
Performanceindicators 30
Conceptualandparameteruncertainty 30
Themanagementofthesafetycase 31
Emergingissues 31
Closingtheissue 33
Theuseofnaturalanalogues 33
Monitoring 34
Step-wisedecisionmaking 34
Continuingresearch 34
Retrievability,reversibilityandlong-termstorage 36
Advancedfuelcyclesandpartitioning&transmutation 36
5
This report analyses the state-of-the-art of science,
technology and procedures needed to implement the
desired end-point in (high-level) radioactive waste
management: deep geological disposal. A range of
topical areas of relevance has been identied:
technical concepts•
regulatory issues•
condence building•
knowledge management•
site selection•
safety cases•
alternative concepts•
governance•
However, this report does not address the engineer-
ing, construction or operation of a repository, such
as excavation, stabilisation, ventilation and drain-
age, waste transportation and waste emplacement
equipment, or the pre-closure operational safety.
Overall it has been observed that a certain level
of maturity has been reached in many scientic
and technical areas important to geological dis-
posal. There is a world-wide scientic consensus
that safe geological disposal is technically feasi-
ble. This observation is supported by the fact that
several countries, including Sweden and Finland,
have dened road-maps for implementation with
specic dates. Other countries, such as Germany
or the UK, may be technically as advanced, but
have not made much progress towards concrete
implementation steps or programmes have (tem-
porarily) foundered, mainly for reasons of public
acceptance. In other countries, particularly those
that have more recently joined the EU, there are
still important decits in knowledge acquisition
and in funding all activities related to the develop-
ment of waste management programmes with geo-
logical disposal as end-point.
Research activities can be divided into site specic
and generic R&D activities. Generic research ad-
dresses fundamental physical and chemical proc-
esses as well materials properties and behaviour.
It may also concern (knowledge) management and
governance processes as well as regulatory proc-
esses of relevance to geological disposal. Site
specic research concerns the generation and col-
lation of data and information on sites that may be
considered for hosting a repository. Usually there is
no clear-cut distinction between these two types of
research. Generic research in a variety of areas has
reached a state of maturity that will allow to proceed
with condence towards a step-wise implementa-
tion. This does not mean that research will stop at
this point. Generic research will have to continue
in response to general scientic developments and
to results from site specic investigations. Generic
research by its very nature has considerable scope
for international collaboration and harmonisation
of concepts and approaches and this will increase
condence in the ensuing results. In fact, collabo-
ration and harmonisation has been practice since
the early days of the EU Framework Programmes.
Site specic investigations have to be repeated
for each national programme, but harmonisation
of concepts and approaches will aid in condence
building among stakeholders.
This study did not identify major conceptual and
research gaps for the host rocks and repository
systems currently envisaged, namely those in (indu-
rated) clays, fractured hard rocks and salt. It is ex-
pected that the nal reports on the EC programmes
FUNMIG and NF-PRO will provide a comprehensive
picture of our knowledge of far-eld and near-eld
processes respectively. It is already sure that cer-
tain processes still require better quantication
and for various coupled (thermal-hydraulic-me-
chanical-chemical) processes models still require
further development. However, the forthcoming re-
sults are not likely to change the principal conclu-
sions on the feasibility of geological disposal.
The report examines in broad terms the various
elements of a deep geological repository system
for high-level waste and/or spent fuel, if the latter
is declared a waste. These elements include the
waste forms, the containers, buffers and backlls,
as well as host rocks. The respective safety func-
tions, such as retention and buffering, are exam-
ined with respect to their conceptual development
and quantitative knowledge.
The safety case is the major instrument to guide
and assess the development of a geological re-
pository. The conceptual approaches and remain-
ing unresolved issues are examined. Overall it can
be concluded that this instrument has already at-
tained a high degree of maturity and further work
mainly addresses condence building issues. How-
ever, not all EU Member States have yet attained
the same level of procedural understanding and
level of application for various socio-economic and
political reasons.
EXECUTIVE SUMMARY
JRC Reference Report
6
Site selection remains a contentious issue and has
to balance technical requirements with constraints
imposed by the availability of suitable host rock
formation on a national basis as well as socio-po-
litical constraints. Repositories shared by two or
more Member States may overcome some of the
above constraints, but face various legal as well as
public acceptance challenges. In any case these is-
sues can only be resolved at the political level.
Demonstration tests are an important instrument in
condence building, both within the scientic com-
munity and with respect to outside stakeholders.
Such tests are mainly carried out in the various Un-
derground Research Facilities (URFs), which in fact
are the focal points for intensive collaboration.
While the scientic and technical community might
be quite condent that implementation can be-
gin, the situation with the regulator and the public
in general may be different. Condence building
among all stakeholders with a view to ‘close’ is-
sues remains an important conceptual and prac-
tical challenge. Two important instruments for
condence building are (natural) analogues and
monitoring activities.
It is important to note that continuing R&D activities
are not a sign of immaturity or lack of condence.
General scientic developments may require to re-
visit even ‘closed’ issues from time to time in order
to demonstrate that the scientic basis for deci-
sions is still valid or with a view to further increase
margins of safety.
Knowledge management issues have found consid-
erable attention in the past few years. While strate-
gies for corporate knowledge preservation and for
preserving general scientic knowledge are being
successfully developed in various other industries,
strategies for the preservation of knowledge about
a repository site over time-scales exceeding a few
centuries are less clear. The most promising ap-
proach appears to be to develop an ‘active’ rela-
tionship between the host community and the site,
so that knowledge is continuously renewed.
A number of terms, such as ‘Best Available Technol-
ogy’ (BAT) or ‘optimisation’ have been brought into
the discussions on radioactive waste management
from other technical or regulatory areas. It may be
argued that these are implicitly covered by the de-
velopment of safety cases.
Retrievability, reversibility and long-term storage
as management options have entered the discus-
sion and respective socio-political or economic re-
quirements will have their bearing on the repository
design and the timing of disposal programmes. The
implications for the safety case are not yet clear,
but it is well understood that these must not com-
promise safety.
Governance issues, i.e. the way a society arrives
at accepted waste management decisions, are
strongly related to condence building. In the wake
of various failed national programmes a para-
digm shift to more participatory decision making
processes has occurred and it is also advocated
in international guidance documents. Such gov-
ernance issues have been studied in a number of
projects supported within both the Euratom and
EC Framework Programmes over the years. It may
be noted, however, that there appears to be only
limited direct interaction between these sociology
oriented projects and the technical R&D projects.
The critical step in implementing waste manage-
ment solutions is regulatory approval. This re-
quires an adequate set of regulations, criteria
for evaluation and that regulators are adequately
enabled. A paradigm shift away from a focus on
human protection only towards environmental
protection
is being observed. Harmonisation of
the regulato
ry framework in Member States meets
with some difculties owing to varying historical
and cultural traditions. However, the NEA LTSC-
project, for instance, concluded that such harmo-
nisation would not be necessary, if consensus can
be achieved over regulatory objectives. It may be
noted that national regulations are typically based
on ICRP and IAEA recommendations, which are
also reected in EC guidance. A possible benet
JRC Reference Report
7
from harmonisation of regulatory criteria would be
that it may help to prevent risk displacement from
one country to another through the development
of shared disposal solutions in countries with less
stringent regulations.
As to the concern that EC, NEA and IAEA have over-
lapping constituencies and possibly overlapping
areas of work and interest, one may note that the
de fa cto roles of the EC can be seen as providing the
policy framework and R&D funding, of the IAEA as
providing regulatory guidance, and of the NEA as
providing the conceptual framework.
ourscienticunderstandingoftheprocesses
relevant for geological disposal is devel-
opedwellenough toproceedwithstep-wise
implementation;
scientic and regulatory co-operation, e.g.
throughtheFrameworkProgrammes,ensures
aEurope-wideharmonisedlevelof scientic
understandingandregulatoryoversight;
mechanismstodemonstrateequivalencybe-
tweenMemberStates’regulationsmightbea
moreefcientway forwardthanharmonised
oruniedregulations;
theawarenessoftheneedtoinvolveallstake-
holdersinthedecisionmakingprocessesto-
wards implementation of geological is now
highthroughoutEurope;
therearestillunresolvedissuesonhowtoin-
volvestakeholdersinpractice;
supportingmoreadvancedcountries in their
effort to move to implementationislikelyto
havesynergeticeffectsinothercountriesby
increasingstakeholderscondence;
thedefacto roles of theEC can beseen as
providing the policy framework and R&D
funding, of the IAEA as providing regula-
tory guidance, whilethe NEA compilesand
analyses the national experience with the
strategicprinciplesandtechnicalandsocial
aspectsofimplementation.
JRC Reference Report
8
Objectives
Research and Development into the various as-
pects of geological disposal of radioactive waste
can look back to a history of some four decades.
The question may be asked with justication which
areas are sufciently well understood so that the
issue can be ‘closed’ and where further work is
needed. In other words: how close are we to pro-
ceed to implementation. Of course, the different
Member States of the European Union that have ac-
cumulated radioactive wastes are at rather differ-
ent stages of development as geological disposal
is concerned. On the other hand, international or-
ganisations such as the IAEA and the OECD-NEA
provide a forum for exchange and thus making ac-
cessible the know-how to all.
Implementation is understood here to begin when
concrete steps to establish a nal repository are
taken, for instance by ling an application to con-
struct a repository, either as an individual national
effort or in the context of shared facilities. On the
other hand, many national programmes are gradu-
ally homing in on particular host rock formations,
with the generic research focussing on it and thus
making a gradual transition into site specic re-
search. From when on a programme can be called
‘implementing’ would also depend on the Member
State’s regulatory philosophy and framework: in
some programmes intensive interaction between
operator and regulator takes place. At some stage
during this iterative process a formal license appli-
cation is submitted. In other countries the opera-
tor develops the safety case without or only with
very limited interaction with the regulator and at
the end submits a license application that is then
either granted or rejected by the regulator.
provide an overview over the recent past, cur-•
rent and planned programmes of the IAEA,
OECD-NEA and the EU in the area of radio-
active waste disposal and to assess them with
respect to the completeness of coverage;
identify those areas that can be covered by •
generic research and thus can be supported
by international collaborative research vis-à-
vis those areas that require site specic in-
vestigations and thus need to be carried out
by national organisations;
identify areas where harmonisation will help •
to reduce resources use and increase stake-
holder acceptance, and to
help to decide when enough research is •
‘enough’ vis-à-vis regulatory acceptance and
implementation of a repository.
The structure of the report is based on a deduc-
tive concept that begins with a descriptions of the
objectives of geological disposal, the natural and
engineered system properties by which these ob-
jectives are to be achieved, the means by which this
is tested and demonstrated, namely in so-called
safety cases, and nally how these criteria are to
be used in selecting a suitable site. Added are ob-
servations on various overarching issues, such as
on condence building within the scientic/techni-
cal community and among the various stakehold-
ers, on governance issues and the implications for
the regulators. Given the fact that research on geo-
logical disposal has been going on for more than 40
years and will continue for perhaps another 50 to
100 years, knowledge management can become a
critical issue that is also discussed in this report.
Note on the use of this report: the key ndings in
each section are highlighted by printing them in
‘bold’ typeface. In addition to the references cited
in the various sections, the reference list contains
additional material for further reading.
Paradigm
It is widely agreed in the scientic and technical
community that geological disposal is the desir-
able management end-point for highly radioactive
materials that arise from nuclear energy systems
and are considered waste. Deep geological dis-
posal appears to be the most reliable post-closure
‘passively’ safe option as stipulated by Require-
ment 5 of the draft Safety Requirements for geo-
logical disposal (IAEA, in prep. f ). Research into
the technical feasibility, the scientic implications
and the safety requirements has been going on for
more than three decades. While one major obstacle
against implementation of such management solu-
tions appears to be their public acceptance, one
may also ask at this point, whether generic RTD
world-wide up until now has adequately covered all
relevant aspects, which open questions are still be-
ing addressed or need to be addressed, and what
further work is needed to demonstrate safety. It is
1. Introduction
JRC Reference Report
9
understood that in practical terms there will be no
clear distinction between generic research and de-
tailed site characterisation work.
It is also important to note that ‘safety’ is a neces-
sary pre-condition, though in practice the decision
of what is an acceptable safety is not necessar-
ily made only by the regulator, but public accept-
ance may have a bearing on it. At the same time,
the regulator has to ensure that other stakehold-
ers’ wishes do not compromise safety. In essence,
a broad societal consensus is needed to enter into
the implementation phase.
Astocktakingexerciseand gap analysis will also
bevaluableinthepreparationof the next Frame-
workProgramme.
Currentstatusofworksupporting
thesafetycase
As will be discussed in detail in Chapter 3, a ‘safety
case’ may be broadly dened as a structured pres-
entation of the evidence, analyses, and lines of rea-
soning related to the long-term radiological safety
of a proposed or actual radioactive waste reposi-
tory. Research and development in supporting safe-
ty cases has been going on for the past 30+ years
and has reached a certain maturity in various topi-
cal areas. The work has been funded largely by the
national programmes (operators and regulators) in
more advanced Member States, but a considerable
amount of resources has also been invested by the
European Commission.
Progress has been thus that scientists and engin-
eers in general are condent that repositories that
will perform as expected over the projected time
horizon of 105 or even 106 years can be built. Never-
theless the long periods of time for which safety
has to be demonstrated remains a key challenge
in the development of safety cases for geological
repositories (OECD-NEA, 2006i).
While disposal research has reached a certain level
of maturity in a number of topical areas, continuing
work is driven by six main factors:
previously identied knowledge gaps,•
changes in the overall radioactive waste man-•
agement concepts, including the introduction
of the requirements for reversibility/retriev-
ability, long-term storage, as well as security
issues, resulting e.g. in different potential
radionuclide source terms or the reaction of
repository components to long exposure to
the atmosphere,
innovations in nuclear energy conversion sys-•
tems, such as a move to higher burn-ups or
new reactor types with different wastes,
to conrm that previous work is still valid •
given new insights coming from other areas
of research,
the desire to further increase the already •
identied safety margins, and nally,
scientic curiosity.•
The rst ve are drivers coming immediately from
within the community of those concerned with
the safe disposal of radioactive waste, namely
the operators and regulators. The last driver re-
fers to academic research that may not be direct-
ed to the immediate needs of the safety case or
performance assessment.
It is important to stress that continuing research
does not indicate a lack of condence in the princ-
iple of geological disposal as such.
The aim of international organisations, such as the
OECD-NEA and IAEA, is to provide a sounding board
for national programmes and to organise collab-
orative work on generic topics so that efforts can
be distributed and resources applied efciently. In
addition particularly the IAEA is working towards a
harmonisation of standards with a view to increase
(public) acceptance of waste management solu-
tions. The membership in these organisations is
different, the OECD-NEA membership being nearly
the same as that in EU25 plus Japan, Canada and
the USA, while the IAEA addresses explicitly the
needs of the less developed countries of their 145
strong membership.
Implementationofanygeologicaldisposalproject
will depend on the preparation of an adequate
safetycaseandonthelicensingauthoritiesdeter-
miningwhatisadequateandacceptingthesafety
case.Itisthereforeusefultoreviewthestatusfrom
bothperspectives.
JRC Reference Report
10
Overview
The fundamental objective of geological disposal
is to retain radionuclides in either the engineered
repository or in the host rock so that they do not
enter the biosphere over a pre-dened time span.
Geological disposal relies on a sequence of com-
plementary and/or redundant barriers (a ‘defence-
in-depth’ concept), namely the waste form, the
container, the buffer/backll, and the host rock
(cf. IAEA, 2003j). Each natural or engineered com-
ponent of the disposal system is assumed to full
certain functions, either alone or in combination.
The relative degree of complementarity and redun-
dancy required depends on the national legisla-
tion and the chosen host rock (see also OECD-NEA
2007g for a discussion on this subject). It may be
noted here that this teleological, engineering-type
concept has come under scrutiny and a more ho-
listic view of how the natural systems will react
to the disturbance introduced by the repository is
gradually being developed among geoscientists.
This view is guided inter alia by insights into how
for instance natural mineralisations are preserved
over very long time-scales.
Three principal types of host rock are currently
under investigation in Europe: hardrocks such as
granite, sedimentary rocks such as plastic or indu-
rated clays, and rock salt. In the USA also volcanic
tuffs are considered (Yucca Mountain). Depending
on the host rock, different emphasis has to be placed
on different elements of the disposal system.
In granites discrete migration pathways will exist,
but their frequency and length is difcult to assess
quantitatively. For this reason more emphasis has
to be placed on the integrity of the waste packages,
the buffer/backll and other engineered elements
of the repository itself. Granitic systems are under
investigation in Sweden, Finland and Switzerland
(as a second option), and are also considered by
the Czech Republic as well as Spain.
Clay formations are chosen such that discrete path-
ways in form of fractures etc. will be minimal. Thus
the retention capacity of the host rock can play an
important role in retaining any radionuclides and
less emphasis can be placed in relative terms on
the other system components. Belgium, France and
Switzerland are investigating this option in various
types of plastic or indurated clays.
In rock salt the main vector for radionuclide migra-
tion, the pore waters, is virtually absent. Thus the
various barrier elements can have a more equal
weighting, although their failure would be due to
any residual water present. Germany is the only
European country that in earnest considers a
disposal option in salt.
Wasteinventory
The radioactive wastes due for disposal in a deep
repository have been in some instances accumulat-
ed over a period of more than six decades. Due to
poor record keeping and a lack of awareness of the
importance to be able to describe source terms ad-
equately, the nuclide composition of many wastes
is not known or not known very precisely. In addi-
tion to radionuclides, certain wastes destined for
deep disposal also contain chemo-toxic elements
or compounds.
2. The Technical Concept of Geological Disposal
Topicalareasofconcern
The tasks towards implementation of disposal so-
lutions can be subdivided into
ensuring that an adequate regulatory frame-•
work is in place
development of a conceptual model,•
providing for the scientic-technical basis to •
support the chosen concepts, and
undertakings to ensure condence among •
stakeholders.
This will be supported by a number of cross-cutting
or overarching areas of research an implementation
work, including resolving governance issues and
ensuring efcient knowledge management.
JRC Reference Report
11
Analysis of the elemental composition of legacy
wastes is often not possible for safety or com-
mercial reasons. Therefore, estimation techniques
based on the knowledge of previous processes and
practices are being developed. The NEA currently
has a project on the isotopic composition of spent
fuel under way (see http://www.nea.fr/html/sci-
ence/wpncs/ADSNF/index.html).
Wasteforms
Two main types of high-level waste, respectively
waste forms, are under consideration for deep
geological disposal in Europe: vitried high-level
waste and spent nuclear fuel, should it be declared
a waste. In other countries (Australia, USA) ceram-
ic- (e.g. VANCE, 2007) or phosphate-bonded (OEL-
KERS & MONTEL, 2008) high-level waste forms are
also under investigation. In addition certain other
wastes containing long-lived radionuclides are also
destined for geological disposal in some countries,
e.g. Switzerland.
A considerable amount of research has been
undertaken to understand the dissolution behav-
iour of glass in the presence of different types of
groundwater and other repository components. As
the choices of repository systems were narrowed
down, glass compositions were developed to suit
the anticipated geochemical conditions. All reposi-
tory systems assume that the vitried waste will
be emplaced in steel cylinders. Most of the current
near-eld designs assume that some argillaceous
material, either bentonite, bentonite/sand, ben-
tonite/crushed rock or crushed clay host rock will
be in immediate contact with the steel, while in the
salt case this will be a mixture of crushed salt and
bentonite. The chemical interaction of these three
systems components has been extensively stud-
ied. The FP6 project NF-PRO in particular aimed to
sum up the current knowledge of glass and fuel dis-
solution and to identify and address any remaining
gaps. While there are indications that this research
area has reached a certain level of maturity, a var-
iety of detail questions remain open and the unex-
pected behaviour of steel corrosion products (see
below) may require further investigation with re-
spect to waste form dissolution. However, experts
seem to agree that these questions mainly concern
the optimisation of the near-eld of a disposal sys-
tem, but would not compromise its fundamental
functioning (HODGKINSON, 2007).
Given the limited number of principal disposal
concepts and the limited number of glass formu-
lations, harmonised approaches to process de-
scription would be warranted. Researchintoglass
corrosion in different types of environments and
duetotheinteractionwiththevariouscomponents
of a repository systems appears have reached a
certainmaturity.
Spent fuel consists mainly of UO2-pellets with the
ssion products contained within. These pellets are
contained in the fuel cladding. Such fuel bundles
are placed in containers made of steel or a combi-
nation of copper and steel. Thus the interaction of
the fuel with the other components of the near-eld
need to be investigated. Similar to glass, an exten-
sive body of research has been accumulated on this
subject. This work indicates rapid dissolution of the
fuel in natural environments and in the absence of
geochemical buffers, such as the alkaline environ-
ment provided by concrete in the repository. Much
ofthebasicresearchintospentfueldissolutionis
ofgenericnatureandequallyapplicabletoseveral
countries’ disposal systems. However, processes
and respective models need to be veried using
site specic materials during the development of
the safety case.
Disposal concepts to date assume waste forms and
spent fuel associated with past and current types
of reactors. New reactor types and changes in the
fuel design will necessitate research into the be-
haviour of the respective spent fuels under reposi-
tory conditions, should they be declared waste and
destined for direct disposal. Given the rising prices
of uranium and general notions of resources con-
servation together with the expectation that more
new reactors will be built, it is not unlikely that the
Member States concerned will review their policies
on direct disposal. However, waste management
organisation have to be prepared for all eventual-
ities and, hence, such research is needed.
Wastecontainers
The main function of the containers or canisters,
once emplaced in the repository, is to provide the
rst physical and geochemical barrier against dis-
solution of the vitried waste or spent fuel. Surface
temperatures of the waste packages will have been
let to drop below the boiling point of water in most
Member States, but the interactions between the
glass matrix and the argillaceous backll materials
JRC Reference Report
12
are difcult to assess under such conditions. In
order to provide this function over the specied life
time, the canisters must also be able to resist the
geomechanical forces that will be exerted on them
after the closure of the repository. This is particular-
ly an issue with the casks for spent fuel. While all-
steel casks are designed to provide the strength in
themselves, copper canisters require steel inserts
to provide more strength against deformation. In
certain disposal systems, such as that envisaged
by Belgium, the primary carbon steel canister is
surrounded by an overpack consisting of a layer of
portland cement cast into a stainless steel canister.
This ‘supercontainer’ thus provides alkaline buf-
fering in addition to mechanical strength and low
hydraulic conductivity. In general, the introduction
of foreign materials, such as alkaline cements,
is being reconsidered as the benet of lowering
radionuclide solubilities and corrosion passivation
is off-set by difcult to predict detrimental effects
on argillaceous materials in the repository system.
In other systems chemical buffering is provided by
the backll.
The number of types of canisters needed is deter-
mined by the various reactor types and their asso-
ciated fuel assemblies that must be accommodated
in the canisters. As with most aspects of the dis-
posal system, one can group the research work into
generic type of research and work that has to be un-
dertaken on country-specic problems. There will
be, however, groups of countries that require the
same type of canister for a similar type of disposal
environment. The project CATT (http://catt.jrc.
ec.europa.eu/) inter alia investigates how transfer-
able waste packaging designs might be. Materials
properties’ and structural strength analy-sis and
modelling have reached a certain maturity. Current
research addresses specic design issues and fail-
ure modes and probabilities.
There have been extensive research programmes
over the past decades into the behaviour of
various types of steel and of copper in the different
engineered repository types. The long-term
behaviour of these materials has also assessed
using man-made analogues, such as archaeological
copper artefacts. Research into corrosion of steel
and copper in aqueous solutions appears to
have also reached a certain maturity, judging by
the smaller number of projects on the subject in
recent years. Whilecorrosion as suchappears to
bereasonablywell understood, ratedetermining
processes,andthebehaviouratinterfaces,suchas
thebehaviourofcorrosionproductsattheinterface
betweensteelcanistersandbackllrequirefurther
investigation(HODGKINSON, 2007).
Corrosion gases generated and their migration
is being addressed in various national and EC
projects, e.g. DECOVALEX (http://www.decovalex.
com/) or PAMINA (http://www.ip-pamina.eu/). For
the NEA-IGSC (http://www.nea.fr/html/rwm/igsc.
html) gas generation and migration was identied
as an important study subject.
More recent developments in the nuclear world,
such as a move to higher burn-up and the
introduction of mixed oxide (MOX) fuels, have
necessitated the revision of container designs,
givingriseforaneedfornewresearchinthiseld.
New and revised designs have to accommodate
higher thermal loads and are exposed to higher risks
of radiation-induced embrittlement of structural
parts. The changed criticality risks – lower risks of
criticality, during the life-cycle of the canister can
also be taken into account.
Additional references: IAEA (1987,1997,2003).
Bufferandbackllmaterials
In virtually all repository designs the residual
space around wastes as well as the drifts and
shafts excavated for operational purposes must
be backlled. This backll is needed to prevent un-
controlled settling of the host rock onto the waste.
In addition the backll may have various additional
safety functions attributed to it. Thus argillaceous
backll materials will provide a hydraulic and sorp-
tion barrier against radionuclide migration. It also
serves to ‘key in’ the repository into the excavation
damaged zone (EDZ), preventing rapid transport
pathways. These safety functions are challenged
by the inevitable drying out after the emplacement
of the hot waste canisters.
In clay and granite systems bentonite or bentonite/
crushed host rock-mixtures are the buffer and back-
ll material of choice in most national programmes,
while in salt systems mixtures of crushed rock salt
and bentonite are likely to be used. As there is only
one country left that considers disposal into salt
formations, namely Germany, there is not much
scope for collaborative research and harmonisa-
tion in this particular area. This applies to both, the
geochemical and the geomechanical aspects.
JRC Reference Report
13
Since the principal clay buffer and backll systems
are largely site independent, they has provided
ample scope for collaborative research, which is
reected particularly in the programmes of the
NEA and the EC and in joint undertakings of these
two organisations.
Mineralogical, geochemical, hydraulic and geome-
chanical aspects are closely related in clays and
often several macroscopic phenomena are control-
led by the same microscopic process. The NEA in
particular has focused for many years the research
in this eld through the ‘Clay-Club’ and their work
on the engineered barrier zone (EBZ, OECD-NEA,
2007a and earlier reports). A comprehensive and
scholarly review of clay as barrier was commis-
sioned by NEA and may have become the ultimate
word, if it had not been cut short by the unexpected
death of its main author. The NEA will have the re-
port completed, but also taking into account the
more practical aspects.
Elevated temperatures will change the mineral-ogi-
cal, geomechanical and hydraulic properties of clays
and it is intended to keep the surface temperatures
of waste packages at the time of emplacement be-
low 100°C. Indeed, storage period and repository
layout is selected to keep the surface temperature
of canisters below this value that has been found to
be critical. The buffer and backll materials will be
put in place with a water content that is at the opti-
mum from a geomechanical point of view, allowing
e.g. maximum compaction. The heat emitted from
the waste will dry out the materials and alter their
suction potential. A complex sequence of dehydra-
tion and rehydration of the materials will result.
Elevated temperatures and the presence of corro-
sion products from waste and containers will also
alter the mineralogical assemblage in the clays,
possibly changing the hydraulic properties due to
precipitation or dissolution of minerals. Such proc-
esses have been studied in small scale laboratory
experiments as well as in demonstration mock-
ups in laboratories and in underground research
laboratories, including the FEBEX in the Grimsel
Laboratory (http://www.grimsel.com/pdfs/g_
febex_de.pdf ). Many of these studies are not only
relevant for buffer and backll material, but clay as
a host rock in general. The new work programme
of the NEA-IGSC acknowledges this in setting up
relevant cross-cutting activities.
Corrosion processes at the interface between can-
isters and structural steel on side and clays on the
other, and to a lesser degree radiolysis, can pro-
duce signicant amounts of hydrogen in a reposi-
tory. This goes in hand with the thermal loading of
buffer and backll material. This complex scenario
of corrosion under changing degrees of saturation
and the fate of the corrosion products is not yet
fully understood and subject of ongoing research
e.g. in the DECOVALEX project and new projects to
be initiated during FP7.
While much of the basic phenomena in clays are
understood, their quantication for given cases
remains difcult. The complexity of the clay
mineralogy makes is often difcult to arrive at
unique explanations and quantitative predictions.
Sources for suitable bentonites are not too
frequent around the World and many have been
extensively studied by now, but the situation is
different with clay as host rock (see below). While
the response of bentonite to changing conditions,
such as water saturation at its boundaries,
temperature, salinity/pH of engrossing water etc.
are reasonably well understood the combined
effect and possible interactions between
different mechanisms are still difcult to predict
quantitatively. It can be expected that the project
NF-PRO will provide a good picture of the current
status of knowledge and further research needs.
It appears that no major phenomena have been
overlookedandfurtherresearchwillaidinquanti-
fyingthefunctioningofbuffersandbacklls,rath-
erthanputtingthesystemassuchintoquestion.
Additional references: IAEA (1990,1992), OECD-
NEA (2003c,2003d,2004c,2005c, 2007a).
Hostrocks
In Europe salt as an envisaged host rock is
unique to Germany and therefore does not offer
much scope of collaborative research, though
the Netherlands may be looking into this op-
tion also. Rock salt in massive formations, e.g.
diapirs, offers some special properties, such as
convergence, which is effecting the sealing of a
repository. Particularly the geomechanical prop-
erties without and with thermal loading have
been studied extensively in Germany, both in the
laboratory and underground facilities (the Asse
former salt mine).
JRC Reference Report
14
The following is mainly concerned with crystalline
rocks and clays. There are three aspects of
the host rock that need to be investigated, its
geomechanical properties, its hydraulic properties,
and its mineralogy and geochemistry. As has been
noted before in the case of clay, these properties
are closely related to each other. This is less the
case for granite.
Waste packages, buffer, backll and surrounding
host rock form a complex system. Excavation of a
repository causes changes in the stress patterns in
the rock, which in turn causes deformation. Some
of the deformation will be passed onto other com-
ponents of the repository after closure.
Miningandtunnellingtechniquescanlookbackto
acenturieslongtraditionandthepracticalaspects
arewellestablished. Each host rock type and the
specic geological setting requires the appropri-
ate tunnelling technique. Tunnelling techniques
have to balance speed and economy with the spe-
cic requirements of a repository. Even more so
than in conventional tunnel projects, it is impor-
tant during excavation to keep the disturbance of
the surrounding rock to a minimum. The properties
of the resulting excavation damaged zone (EDZ)
have been and continue to be investigated in de-
tail, as they will inuence the overall permeability
of the backlled and sealed repository. As several
waste management programmes move towards
actual implementation, such construction and con-
structability issues nd more attention in the re-
spective R&D programmes.
Excavation will result in stress release and in-
creased permeability due to the opening frac-
tures etc. These can be sealed to some extent
using geo-engineering techniques, but the seals
may be subject to erosion over long time scales.
Some clays exhibit self-healing properties e.g.
due to convergence and this advantageous prop-
erty has been investigated in detail from both, the
scientic and geo-engineering point of view. The
self-sealing and self-healing properties of rock
salt due to creep and convergence also have an
important safety function in repositories in this
type of host rock.
The DECOVALEX project investigates the heat
transfer, uid ow and stress/deformation/
failure in rocks and buffer, and their interactions
(coupled THM) over a few hundreds of years from
excavation to post-closure. While the development
of numerical modelling tools can be undertaken
on international level, much of the actual process
investigations have to be site specic, taking into
account the specicities of the geology selected.
Tunnels and other excavations in hard rock are usu-
ally stable over prolonged periods of time and do
not require any lining for geomechanical reasons.
In clays and salt the convergence, which is a de-
sired property during and after closure, requires
built structures to keep the excavations open. This
will introduce considerable amounts of steel and
concrete into the repository environment. While
the concrete has desirable effects on the geochem-
ical environment by lowering the solubility of many
radionuclides, its effect on the various clays can be
detrimental and their properties have to be care-
fully chosen. Overall there seems to be a growing
consensus that at least in repositories that are con-
structed in clays as host rocks only a minimum of
additional foreign material should be introduced.
By the same token, alteration processes that occur
during the operational phase, such as oxidation of
suldic minerals, will have some inuence on both,
the geomechanical properties and the geochemical
properties of the near-eld. Such processes are the
subject of the IP NF-PRO.
Considerations of constructability have several
implications for the repository design. When
locating a repository, or parts of it, at the chosen
location one will generally aim for areas that are as
homogeneous and undisturbed as possible. This
has both advantages for the isolation of the waste
and the safety of construction. Fault zones would
provide pathways for migration and may also provide
additional challenges during the construction of
drifts and other excavations. Geotechnical measures
to make safe certain parts of the excavations, for
instance by rock anchors, will introduce additional
foreign material into the repository and may have
to be considered in the safety case. As the actual
construction of the repository proceeds generally
an optimisation process will have to be put into
place that weighs the various technical constraints
and safety objectives.
The introduction of new operational concepts, such
as retrievability and long-term (> 100 year) under-
ground storage, results in increased requirements
for the geomechanical stability of the open spaces
JRC Reference Report
15
in a repository. Processes such as convergence
and the ‘weathering’ of exposed rock surfaces will
have to be approached in a slightly different way
under those circumstances. The implications of
delayedclosurehavebeenrecognised,butnotyet
fullyinvestigated.
Additional references: IAEA (2001,2003), OECD-
NEA (2004d,2005b).
Concerning their permeability, geological materials
are usually classied either as conducting in their
porous matrix or along discreet features, such as
fractures. This distinction, which was originally de-
veloped in the context of water resources investi-
gations, is not so clear-cut in the low-permeability
rocks chosen as host rocks for a geological reposi-
tory. Even granites that are typically considered to
conduct on fractures only, can have a considerable
water-lled ‘porosity’, though no or only negligible
water movement may take place in this porosity do-
main. Conversely, there are also indurated clays in
which there can be considerable water movement
along fractures.
The average permeability of rocks is scale de-
pendent or in other words a reection of the het-
erogeneities in the rock. Single, high-permeability
features may dominate the permeability at any
scale. While the properties of such features can
be assessed in the laboratory and the eld, their
frequency, spatial persistence and distribution is
more difcult to elucidate.
For fractured rocks various in situ experiments
such as those at the Grimsel and Äspö sites are
aimed to develop methods for describing quan-
titatively the distribution of fractures and their
hydraulic functioning using modern borehole geo-
physical techniques in combination with tomo-
graphic imaging. Tomographic imaging techniques
in combination with modern analytical techniques
such as positron emission tomography (PET, e.g.
GRÜNDIG et al., 2007), or the permeation of rock
samples with acrylic resins doped with radiotrac-
ers followed by autoradiography (LESKINEN et al.,
2007), help to better understand ow-path distri-
bution on the cm-scale.
This distribution, their interconnectivity and per-
meability at a regional scale cannot be known
with certainty, but has to be approximated using
statistical techniques. Even more difcult to cap-
ture are time- and scenario-depended changes in
permeability due to, for instance, blocking of ow-
paths by the precipitation of secondary minerals or,
conversely, corrosive dissolution. The net effect of
the respective variability in parameter value distri-
bution can be investigated by developing ‘what if’-
type scenarios and sampling the system response.
A variety of models for this purpose has been de-
veloped over the past decades both, within the rad-
waste community and in other geoscientic areas.
This kind of uncertainty is also the subject of col-
laborative project PAMINA (http://www.ip-pami-
na.eu/). While there is considerable addedvalue
in international collaboration in thedevelopment
of the respective techniques, actual assessments
willhavetoberepeatedateachplannedrepository
siteinthecontextofdetailedsiteinvestigation.
Depending on the geographical location, hydraulic
conditions and other properties are expected to vary
over longer time-scales. For instance, a glaciation
is likely to reduce horizontal permeability as some
fracture systems will close due to an overburden of
several kilometres of ice. In any case, the ice cover
will change the regional ow patterns by provid-
ing additional head and by modifying the recharge
areas and recharge rates. Akin to all climatological
models, predicting the extent and distribution of
an ice cover over Scandinavia or the Alps is fraught
with many uncertainties. For constructing the safe-
ty case for repositories located in areas that may be
subject to glacial conditions at some time, it may
be more effective to understand whether and how
the ow patterns at repository depth would be sig-
nicantly changed. Various national and projects
under the IP FUNMIG have targeted this question
utilising for instance various isotope techniques.
The movement of water in clays is more controlled
by physico-chemical effects rather than by classical
uid mechanics. Unless fractures provide a fast
pathway, water movement in clays is very slow.
This is conrmed on a long time scale and over
considerable distances by salinity and isotopic
studies. The bulk permeability of clays can be
signicantly changed by ingressing uid whose
constituents may interact with the clay minerals.
Saline or high pH solutions, such as those
resulting from contact with concrete, can increase
permeabilities by disaggregation and reduced
swelling pressure. Rearrangement of the mineral
assemblage due to corrosion and newly formed
minerals can lead to permanent changes. Some of
JRC Reference Report
16
these changes may be considered detrimental to the
retention capacities of the clays for radionuclides.
These processes have been extensively studied and
continue to be studied under the IPs NF-PRO and
FUNMIG. Not all of the mineralogical processes are
yet quantitatively understood. Once a repository
site has been selected and site investigation work
has begun, some of the interaction studies will have
to be repeated with the actual materials present in
the area where the repository will be excavated.
Additional references: IAEA (1999a), OECD-NEA
(1997b,1999b,2001a,2001b),
Processesaffectingradionuclidebehaviour
Permeability and the mechanisms controlling
the migration of (dissolved) constituents in the
porewaters are closely related. There is a wide
spectrum of physical and chemical processes that
lead to the distribution and effects the retention of
constituents. The scale of the responsible features
and associates processes may range from the
kilometre-scale to the molecular level. Thus the
migration behaviour of radionuclides is determined
by the hydraulic properties of the respective host
rocks, the chemical properties of the element in
question and by the mineralogical and geochemical
properties of the material, buffer/backll material
or host rock, in which migration occurs.
The way how the water itself moves in the various
types of materials on a laboratory scale (cm to dm)
is becoming reasonably well understood. With con-
siderable success tracer migration has also been in-
vestigated in small domains, such as single fracture,
utilising rock laboratories such as those in Grimsel or
Mol. One RTD component of the IP FUNMIG (http ://
www.funmig.com/) is directed to investigate the re-
spective processes and their upscaling. Processes
at the molecular level nd increasing attention.
Clays, as buffers and backll materials as well as
host rocks, have been studied extensively with re-
spect to their mineralogy and how it may change
when in contact with different repository materials.
Various national programmes and namely the Clay
Club (http://www.nea.fr/html/rwm/clayclub.html)
participants studied how radionuclides are retained
and how this retention is changed in contact with
different repository materials (OECD-NEA, 2005b).
While geochemical processes in clays have been
studied extensively for the past three decades,
these processes have found less attention in gran-
ites. The general notion has been that the major
retention capacity is provided by fracture inlls,
that may be similar to clays or by a largely physical
process that was dubbed ‘matrix diffusion’. Owing
to the generally lower geochemical retention ca-
pacity in granites, compared to clays, safety cases
for repositories in such rocks place more emphasis
on the engineered barriers.
Advection, hydrodynamic dispersion and diffusion
are the physical processes that shape the con-
centration distributions of radionuclides released
from a repository. In soft clays diffusion will be the
dominating process, while in indurated clays there
may be also advective transport along fractures.
Advective transport dominates in fractured rock,
provided there are no signicant fracture inlls. On
the macroscopic level the presence of an assem-
blage of owpath of differing length as well as the
velocity distribution within open fractures leads to
the phenomenon that is dubbed as hydrodynamic
dispersion. These dispersion phenomena lead to
a lower peak of absolute concentrations, but not
to retention sensu strictu, meaning that the total
mass of migrating radionuclides is not lowered.
The physical process that leads to retention and on
which safety cases for repositories in host rocks
such as granites have increasingly come to rely
on is the one called ‘matrix diffusion’. Here one or
more classes of water-lled ‘pores’ are observed,
in which no advective movement takes place. Ra-
dionuclides diffuse into these pores driven by con-
centrations gradients. When concentrations in the
adjacent fractures drop below those in the matrix,
the radionuclides are released again. As in the case
of dispersion, this phenomenon lowers the peaks
of absolute concentrations, but does not reduce
the total mass of migrating radionuclides, unless
these are xed by e.g. precipitation.
While in the past diffusion processes were studied
using short rock columns that were treated largely
as ‘black boxes’, progress in analytical and model-
ling methods is leading to a better understanding
of processes at the microscopic level. IP FUNMIG
has a dedicated RTD component on this area that
has fostered signicant progress. These investiga-
tions focus less on the purely physical processes,
rather than on their combination with sorption and
(co-)precipitation processes.
JRC Reference Report
17
Thereappears to bea wide consensusinthe sci-
enticworldthat argillaceousmaterials and rock
saltashostrocksarecapableofsufcientlyretain-
ing the relevant radionuclides. Ongoing research
is mainly directed towards fur therincreasing the
safetymarginsandtodemonstratetheoverallre-
silienceofthedisposalsystemstoabnormaldevel-
opmentsintheneareld.
Theretentioncapacitiesoffracturedrocksarelow-
erandmoredifculttopredictquantitativelyover
thelongterm.
Additional references: GRENTHE & PUIGDOMENECH
(1997), IAEA (1989,1999f, 2005a, 2005c, in press),
OECD-NEA (1997b,1998,1999b,2000a,2001a-
c,2002a,2005b,2005g).
At the beginning of the research into geological
disposal many fundamental thermo-chemical
properties of the majority of radionuclides were
not known or not known quantitatively. Thus the
occurrence of certain oxidation states of plutonium,
neptunium and americium was debated. A wide
eld of research has been the chemical forms, or
speciation, of uranium and transuranic elements in
such complex media, as are porewaters in geological
materials. Most of the fundamental research into
the chemistry of these elements has been carried
out under conditions far from those occurring in
nature with respect to element concentrations,
ionic strengths, and ligands present.
Various projects had been initiated over the past
two decades at EU and NEA level to address this
problem of missing and inconsistent thermo-
dynamic data, e.g. the CHEMVAL-project (FALCK
et al., 1996). The NEA Thermodynamic Database
Project (http://www.nea.fr/html/dbtdb/) in partic-
ular has helped to improve this situation by critically
reviewing the available data, by identifying gaps and
by providing the rationale for targeted research. In
addition signicant progress has been made in the
development of a variety of spectroscopic techniques
that allow the observation of speciation under con-
ditions that are close to those found in nature.
It was found that there were knowledge gaps not
only in the chemistry of uranium and transuranic
elements, but also in the chemical properties of
various common major elements. The workplan for
the NEA TDB project for 2008 and beyond addresses
some of these gaps explicitly now. This work is also
driven by the needs and ndings of performance
assessment calculations. Thus in recent years certain
ssion products, such as selenium, have come
into focus. The underlying causes for this change
in focus are a better denition of the repository
radionuclide inventory and an improved design of
the repository barriers that are expected to retain
efciently uranium and transuranic elements. Work
towards better understanding the (geo-)chemistry
of those ‘new’ radionuclides is ongoing.
A major gap throughout the thermochemical
databasescontinuesto be temperaturecorrection
data for equilibrium constants The majority of
speciation experiments have been and are carried
out under standard laboratory conditions, i.e. at
25°C and ambient pressure. A limited set of high-
temperature data are available for some major ions
that are found to be of interest for hydrothermal
systems. While these would be relevant for the im-
mediate area of the engineered repository, there is
still a gap for the temperature range between 25
and 150°C that would be expected in the backll
and the host rock.
Another well-known gap are data to support ad-
vanced models for activity correction at higher
ionic strengths, such as that proposed by PITZER
(1991). Currently only data for some major ions are
available. These corrections will be needed when
the drying out of the buffer/backll is to be mod-
elled and for far-eld migration calculations with
salt as host rock.
The IP FUNMIG comprises work packages to ll
gaps in the thermodynamic data, with particular
emphasis on compounds relevant to geological
disposal. Further work on actinides will be carried
out under FP7.
Precipitation of pure phases, co-precipitation and
sorption as processes can be reasonably well de-
ned under equilibrium and laboratory conditions.
In many natural systems, however, the respective
reactions will be neither instantaneous nor revers-
ible; it becomes difcult to distinguish between the
three processes.
Sorption on near- and far-eld materials has been
studied for decades by now. In the early years pre-
dominantly batch experiments were carried out,
JRC Reference Report
18
but it was soon realised that the conditions inves-
tigated were far from any realities in the eld. The
usual method of evaluating these experiments, re-
sulting in a single value for the distribution co-ef-
cient (Kd-value) was recognised as not reecting in
situ conditions and not to have any prediction ca-
pabilities. Nevertheless, Kd-values are still widely
produced and then used in performance assess-
ment (PA) calculations. The underlying reason is
that (probabilistic) PA calculations require simple
models in order to keep CPU-times at a reason-
able level. More mechanistic descriptions of sorp-
tion with a larger number of adjustable parameters
would result in a calculational complexity that
would be difcult to manage. A wide range of mod-
els to describe sorption and its various controlling
factors, including competing individual ions, major
ion concentration, pH-value, has been developed
over the years. Obviously, the more variables a
model has, the better it can be adjusted to a given
reality, but in practice it is impossible to parameter-
ise all of these variables over the whole domain to
be investigated. The NEA Sorption Project intends
to nd a compromise between the sophistication of
thermodynamic sorption models and the practical
requirements of performance assessment. Hybrid
models that bound possible changes and provide a
parameterisation within these boundaries are be-
ing developed.
Simple pure phases involving radionuclides other
than uranium are not likely to occur in the far-eld.
Along the potential migration pathways of radionu-
clides a wide variety of precipitation and dissolu-
tion reactions between major system constituents
can and will occur as the system develops and time
progresses. Studies on natural systems have prov-
en very valuable in helping to understand the fate
of e.g. uranium. However, many other radionuclides
do not occur in nature or have suitable analogues.
The structure of many of various naturally occurring
solid phases will be such that radionuclides can be
accommodated in their lattice. In other words solid
solutions and co-precipitation can occur. A compre-
hensive review of solid solutions as a process and
a state-of-the-art proposals for its description have
recently be completed on behalf of the NEA (BRUNO
et al., 2007).
Reactions within the aqueous phase are fast on
the time-scale of interest for a repository. For het-
erogeneous reactions this is not necessarily so and
reaction kinetics can become a controlling factor.
The Damköhler-number would indicate, whether
reaction kinetics need to be considered in a given
system, but veryfewheterogeneousreactionkinetic
dataareavailabletothisdatefornaturalsystems.
The majority of the radionuclides of interest in the
context of nuclear waste disposal occur in several
valence states that may have distinctively differ-
ent geochemical mobilities. In general, the reduced
state is less mobile than the oxidised state, for in-
stance U(IV) vs. U(VI). It has been the objective
of all near-eld engineering designs to provide a
high-pH environment, as under high pH values the
solubilities of most metals are relatively low. Con-
versely, there have been not been such decided at-
tempts to control the redox environment. It is tacitly
assumed that the corrosion of structural steel and
ferrous metal packages would result in a reducing
near-eld environment.
Experimental investigations, whether on the near-
eld or on the far-eld, are frequently hampered
by the fact that it is difcult to achieve anaerobic
conditions in the laboratory or even in tests in un-
derground research laboratories.
In any case, the construction and operation of a
deep repository will result in a redox anomaly un-
derground that is likely to take considerable time to
dissipate. This process requires a sufcient redox
buffering capacity of the surrounding host rock and
of the far-eld as a whole. While this may be not so
much of concern in the context of clay host rocks,
as these frequently contain signicant amounts of
reducing minerals such as pyrites, the situation is
different for fractured hard rock. The question here
is also whether the radionuclides experience suf-
ciently long residence to become reduced.
These and related processes and properties re-
main to be studied in depth in FP7 under the
projectReCosy.
While complexation by simple inorganic and
small organic ligands is being treated within the
various TDB projects, complexation by organic
macromolecules has been treated as a separate
issue owing to the wide variety of possible inter-
actions and of molecule species involved. These
fulvic or humic acid molecules may range in size
from small dissolved molecules to large ones
JRC Reference Report
19
that would classify as colloidal particles. Colloi-
dal particles, which range in size between 1 nm
and 1 μm, can also have inorganic sources, such
as eroded clay minerals or precipitates of major
ions or radionuclides from porewaters. A variety
of models to describe the binding behaviour in-
cluding interaction with discrete binding sites and
unspecic interaction due to their polyeletrolytic
properties (surface complexation) have been pro-
posed. At the same time it has been attempted
to devise sampling and analytical techniques to
investigate colloids and macromolecules as such
as well as their complexing behaviour without
disturbing the natural state. These activities had
been harnessed together under EU and NEA aus-
pices in what became known as the CoCo-Club,
the Colloids and Complexes Club.
Owing to the difculties in working with (redox-
sensitive) transuranic elements and ssion prod-
ucts, much of the work on complexation by fulvic
and humic substances to date was carried out with
uranium. Inconsequence,therearestillconsider-
ableknowledgegapsasfarastheotherelements
areconcerned.
Anothereldthatstillisnotverywellunderstood
is the trilateral interactionbet ween micro-organ-
isms,organic(macro)moleculesandradionuclides.
Thebodyofresearchonthissubjectislimited.
Many of the knowledge gaps with respect to or-
ganic macromolecules are attributable to the very
complex and changeable nature of these mole-
cules. Unlike other constituents, such as inorganic
molecules or simple organic molecules, they do not
re-appear necessarily as the same identiable com-
pound. Important parameters, such as conforma-
tion or molecular mass, can also easily be changed
by sampling and measuring procedures.
Thus, while the problems and their origin have
been established, a solution is not straightforward.
There is still much more experimental work re-
quired to quantitatively understand the behaviour
of transuranic elements and ssion products (and
indeed most metals) in waters containing fulvic and
humic substances. However, a sensitivity analysis
within the performance assessment will show to
what extent these uncertainties will inuence the
nal outcome of the PA. Projects such as PAMINA
(http://www.ip-pamina.eu/) will offer some guid-
ance for determining when enough research in the
context of a particular site has been done.
Inorganic colloid formation was recognised as an-
other vector for enhanced radionuclide migration.
Since colloids are not an entity, but rather a state
of matter in the aqueous phase, their state is easily
disturbed by sampling procedures. A range of so-
phisticated analytical techniques have been devel-
oped to investigate the interaction of radionuclides
with colloidal particles.
A major source of colloids in a repository system
is the bentonite buffer and backll. Many experi-
ments aimed to understand the migration of such
colloids into the surrounding hard host rock have
been carried out and continue to be carried out.
Colloid generation is a function of the very specic
geochemical conditions at a site and in the mate-
rial under investigation. For this reason it is likely
that such investigations have to repeated for each
chosen repository design and assemblage of ma-
terials. Colloid transport is also a function of the
geochemical and ow conditions.
Colloid mediated transport of radionuclides is of
particular concern as experimental evidence points
to effects such as size exclusion, which may consid-
erably speed up the migration of colloids. The actu-
al distribution of radionuclides in the three-phase
system water-colloid-rock is still difcult to predict
and subject of continuing studies. While there is
clear evidence for colloid-mediated transport of
someradionuclidesfrom laboratory experiments,
thereal importanceof thismechanismsoverlong
distances and long times scales needs to be as-
sessedquantitativelyinthecontextofasensitivity
analysis, e.g. by making assumptions about en-
hancedsolubilityorsizeexclusioneffects.
The potential importance of microbial activity
for the evolution of the repository-relevant geo-
chemical systems has long been underrated.
This is not so much due to the neglect by those
specically involved in research on geological
disposal, but rather a phenomenon common to
all work on geochemical systems. It has often
been reasoned that microbial activity cannot al-
ter thermodynamics and thus the end points of
chemical reactions are independent of microbial
activity, which only would effect reaction rates.
However, there may be several possible reaction
pathways, each with a different end-point. As
the actual pathways being followed may depend
on the reaction progress per time unit, microbes
JRC Reference Report
20
might well be a determinant factor in outcome of
a reactive chemical system.
In comparison to other geochemical research, bio-
geochemical research has found comparatively
little attention in the context of deep geological
disposal. This in spite of the fact that over the past
twenty years viable microbial communities have
been found even at great depth in geothermal sys-
tems on land and off-shore.
Biogeochemical processes are one work package
of the IP FUNMIG. The existence of micro-organ-
isms in rocks at sites considered for deep reposi-
tories has been demonstrated nearly ten years ago
(e.g. PEDERSEN, 1999). Only a few laboratories are
undertaking research on the interaction of micro-
organisms with radionuclides of interest (e.g. MOLL
et al., 2007).
Overallthequantitativeroleofmicro-organismsin
repository development and far-eldmigrationis
notfullyunderstoodyet.
Gasgenerationandmulti-phase
owprocesses
There are several situations in or around a reposi-
tory, where the ow of more than one phase has
to be considered. Corrosion of ferrous compo-
nents will change not only the geochemical redox
environment, but will be also, together with ra-
diolysis, a possible source of gases within a re-
pository for high-level radioactive waste and/or
spent fuel. Signicant amounts of hydrogen can
be produced in a repository.
As these corrosion processes go in hand with de-
hydration resulting from the decay heat emitted
from the waste, there has been a concern about
a possible fast dissipation of the hydrogen and
other, radioactive gases through cracked back-
ll materials and the surrounding host rock. It is
still not clear whether the production of corrosion
gases would result in a three-phase system and
whether the overpressure could result in frac-
tures opening which then would provide fast mi-
gration pathways.
The amount produced and time distribution of the
gases arising depends on various factors during
repository evolution. Corrosion rstly depends on
the availability of water, which in turn is a function
of the saturation process after closure, counter-
acted by the heat dissipation from the waste. The
dissipation of any gases generated depends on the
geomechanical and geochemical repository evolu-
tion as a whole, with many closely coupled proc-
esses and process feedback. Individual processes
may be reasonably well understood, but not so the
complexity of the system.
Thereis only a limitednumber ofconceptual and
numericalmodellingtoolsavailableforsuchcom-
plexandtransientprocesses. Hence, gas genera-
tionandtransporthasbeenearmarkedforfurther
investigationinFP7aswellbytheNEAIGSCintheir
workprogrammefor2008andbeyond.
Interactionbetweenrepository
components
The processes discussed above do not occur in iso-
lation, but interact in a variety of ways. Particularly
in the near eld mechanical, hydraulic, thermal and
chemical processes are interacting in order to dis-
sipate the various man-made disturbances. These
processes are mostly far from steady state and
rather transient in nature. Several international
projects currently address these problems from an
experimental and modelling perspective, including
the DECOVALEX project.
An engineered repository effectively constitutes
a geomechanical, hydraulic and geochemical
anomaly within the host rock body. A considerable
thermal and chemical potential is stored within the
waste and other components of the engineered
repository. These potentials will lead to a wide
variety of interaction of the components with each
other and the surrounding rock. This has been rec-
ognised for a long time and a considerable amount
of research in the national and international pro-
grammes has been directed towards understand-
ing these interactions.
The different engineered repository components
are either put in place to full different ‘safety
function’ or are necessary for constructional and
operational reasons. Thus concrete may be used
in waste packages to create an alkaline environ-
ment that exhibits low solubilities for the radionu-
clides in question. At the same time the alkaline
plumes originating in the cementitious compo-
nents of the repository are of concern as they may
alter the (e.g. swelling) properties of argillaceous
JRC Reference Report
21
backll materials and host rocks in a detrimental
way. Hence, the interaction between alkaline solu-
tions and different types of clays has been exten-
sively studied in past. The further interaction with
corrosion products from steel waste packages and
structural materials forms part of the work under
NF-PRO. Whilethegeochemicalandmineralogical
aspectsofthealkalinetransformationsoftheclays
are reasonably well understood, the interaction
withsteel corrosion products and other feedback
andcouplingmechanismsintothegeomechanical
propertiesdeservefurtherinvestigation.
Regionalgeologicalsetting
A geological repository will form together with the
wider surrounding geology the system that is nec-
essary to prevent radionuclides from reaching the
biosphere. Therefore, system parameters and ma-
terials properties not only in the immediate vicinity
of the repository are of relevance, but also those of
the surrounding ‘catchment area’.
Given a planning horizon in the order of 1 million
years, a rst general site selection criterion would
be geological setting that has been stable for sev-
eral millions of years and is expected to remain
stable for several more millions of years. Stable
does not necessarily mean ‘no change’, but rather
settings with slow, steady and predictable changes
can be of advantage. Relevant changes can be of
tectonic or climatic nature.
The climate provides important boundary con-
ditions – past, present, and future one, for the
hydrogeological system (IAEA, 1999a). Ground-
water is expected to be the main vector for ra-
dionuclide migration. Slow rates of recharge
and discharge and, hence, slow rates of turn-
over are of advantage. Over the past decades
groundwater dating techniques using various
stable isotopes and radionuclide decay chains
have been developed. Such methods can not
only be applied to groundwater samples, but
also to uid inclusions in newly-formed miner-
als for instance. Using such methods, it could be
demonstrated at sites considered for the con-
struction of deep geological repositories that
ground- and porewaters have ages of several
million years. This indicates that effectively no
exchange or movement of water has taken place
over this period of time, that the main vector for
radionuclide migration is absent.
In addition, the actual site within a geological for-
mation can be chosen so that owpath lengths to
the surface and mixing/dilution are maximised. For
instance, in an earlier UK site selection programme
one of the pre-stated conditions was that hydraulic
gradients and regional groundwater movements
would be pointing towards the sea. Low perme-
ability formations in basin structures with recharge
from the margins only would be of similar advan-
tage, as discharge can only occur as ‘leakage’
across layers or fault zones. Current groundwater
ow patterns can be evaluated using numerical re-
gional hydrogeological models.
Signicant changes in climate, such as glacial peri-
ods, will have a profound effect on regional and lo-
cal groundwater circulation patterns. Groundwater
ages in the order of millions of years in argillaceous
formations for instance foreseen for geological
repositories indicate, however, that these areas
have not been affected by the last glaciations. The
situation is different for repositories planned to be
built at the margins of the Fenno-Scandian shield.
Glaciation is expected to profoundly change circu-
lation patterns in fractured hard rock. The scientic
debate is going on about how deep oxidising melt
waters would penetrate and how the transients of
accumulating and retreating iceshields will affect
actual circulation patterns.
A further subject of deliberation and debate are in-
frequent tectonic or volcanic events. These issues
are usually addressed by expert opinion in conjunc-
tion with statistics. While a geologist or geophysi-
cist may have a good ‘feeling’ for such issues, it is
difcult to quantify such aggregate personal expe-
rience for use in safety assessments.
In Europe, after 150+ years of geological research
we have accumulated a wealth of information that
3. Siting of Repositories
JRC Reference Report
22
allows us to draw quite a detailed picture of the
geological formations in the top few hundred
metres of the Earth’s crust. Further relevant de-
tails have to be gathered during the site selec-
tion and site investigation process. In the rst
instance preference is given to non-invasive tech-
niques, such as seismics. Seismic techniques
have greatly proted from the extensive devel-
opments in computing hard and software, which
are needed for the modelling and interpretation
of the recorded signals. Much of the relevant
technology has been developed in the context of
hydrocarbon exploration. This and other elds of
geological research are concerned with develop-
ing a three-dimensional picture of geological for-
mations. Other such elds include facies analyses
that use knowledge of the genesis of sedimentary
formations to make predictions about the lateral
extent and distribution of internal structures in
sedimentary rock bodies. Such analyses are also
supported by geostatistical techniques, includ-
ing for instance kriging. Such geostatistical tech-
niques are also used to make predictions about
the spatial distribution of discontinuities such as
faults and fractures.
It should be noted that invasive techniques, such
as drilling, have to be used judiciously in order
not to compromise barriers. Pre-existing bore-
holes from earlier explorations for raw materials,
including water, can pose a signicant problem
as standards and requirements for backlling
were not adequate or have not been obeyed. Such
boreholes can provide short-circuits between dif-
ferent geological formations that are difcult to
evaluate quantitatively.
Overallthe techniquesand(numerical)modelsto
investigate the regional and local geological and
hydrogeological situation are sufciently mature
fortheneedsofgeologicaldisposal.
Strategies for using all available geological and
hydrogeological information are being currently
developedwithaviewofanintegratedassessment
inthecontextofthedevelopmentofsafetycases.
It may be noted that this emphasis on ‘integration’
reects a paradigm shift in approaching the prob-
lem of deep disposal, away from an engineering
approach towards an approach that tries to under-
stand repository evolution as a response of the ge-
ological systems to the foreign body ‘repository’.
Selectionstrategies
On a purely scientic and technical basis, two
strategies for site selection are thinkable: one can
pick a single site that is likely to be suitable and
then attempt to demonstrate its suitability through
safety cases. Scientic logic has it, however, that
‘suitability’ cannot be demonstrated, only unsuit-
ability. It is largely a question of how ‘suitability’
is dened. In the simplest instance it could mean
that a given set of repository related parameters do
comply with a set of pre-dened objectives. This
assumes, of course, that the pre-dened targets
are relevant and adequate. It may not be possible
to be sure of the latter.
Alternatively, one can subject a range of potential
sites to a series of preliminary safety cases that
are designed to eliminate those that are unsuitable
or less suitable than others in the set. In practical
cases the choices tend to be bounded by the types
of host rocks available in the particular Member
State. A possible outcome of such strategy is that
no suitable site exists on the territory of the Mem-
ber State in question. In practice, the site selection
process is complemented by preliminary design
studies. Site selection is a process that iterates
between identifying desirable site properties and
engineering features that complement the natu-
rally available site properties (IAEA, 1990, 2004c).
Based on the concept of multiple, complementary
and redundant barriers host rock and engineered
repository features together prevent that radionu-
clides reach the biosphere. Ideally, the engineered
features would only increase the safety margin, but
considering the availability of suitable host rocks,
some countries will have to put relative more em-
phasis on the engineered features.
It is possible to develop a catalogue of criteria by
which suitable regions can be identied. This cata-
logue would be based on the catalogue of FEPs (Fea-
tures, Events, Processes) by trying to identify sites
that have a maximum of desirable FEPs while mini-
mising those that are undesirable. Fundamental cri-
teria include, for instance, long geological stability,
low hydraulic gradients and permeabilities, low ge-
ochemical and other potentials, etc. In other words,
a geological system is sought out that exhibits in
its natural state a low potential for change and very
slow rates of change. In most Member State there is
a certain amount of knowledge about the geology
already available that directs the search and elimi-
nates particular regions at a very early stage.
JRC Reference Report
23
The basic criteria for site selection are host rock in-
dependent and, therefore, can be developed on an
international basis. A harmonisation of the basic cri-
teria would also ensure equal treatment of regions
within a country and the European Community as
a whole. It would also facilitate trans-national so-
lutions, whether these involve shared repositor-
ies (cf. project SAPIERR, http://www.sapierr.net/)
or shared designs and other facilities (cf. project
CATT, http://catt.jrc.nl/). Due consideration has
tobegiventothefactthatrepositoryprogrammes
arequitefaradvancedinseveralcountriesalready;
establishing such harmonised criteria shouldnot
puttheseprogrammesinjeopardy.
In practice, site selection is likely to be bounded also
by non-scientic and non-technical criteria, such as
the local acceptance, the availability of infrastruc-
ture, pre-existing nuclear activities, and a range of
other socio-political and economic factors. In the
past these considerations were often not made ex-
plicit. However, many national programmes now are
introducing features to allow such considerations
to be made explicit, in appropriate partnership
with local and regional stakeholders (OECD-NEA
2007b). Becausevaluesystems,perceptions,legal
systems,sitinghistory,etc.varyamongcountries,
sharingofbestpracticeisconsideredmoreappro-
priatethanwouldbeaharmonisingapproach.
Given the fact that three major groups of promising
host rocks have already been identied and basic
repository designs developed, the iterative proce-
dure of site selection can probably be shortened for
Member States newly entering into this phase.
Humanintrusionriskasacriterion
Site selection may also be the only viable strategy
to minimise the risk of inadvertent human intrusion
beyond a time-frame within which institutional
control can be reasonably assured. Thus reposi-
tory sites are chosen such that, based on today’s
knowledge and needs, they would have as little
potential as possible for raw materials (minerals,
ores, coal, oil, gas), (drinking) water or geothermal
energy. This criterion would apply to all formations
above and below the host formation and, of course,
the host formation itself. Certain repository design
features also aim to minimise the consequences of
inadvertent intrusion.
4. Regulating Geological Disposal
Fundamentalobservations
A recent NEA report summarises the regulatory ap-
proaches to geological disposal and the underlying
radiation protection criteria and societal processes
ranging from the policy making to the implementa-
tion level (OECD-NEA, 2007d). This report provides
a concise yet comprehensive overview over its Mem-
ber States’ regulatory systems and the underlying
regulatory philosophies. Signicant differences in
the regulatory criteria between different countries
were found. Thus dose constraints span a range
from 0.1 to 0.3 mSv/year, while risk constraints are
either set at 10-5 or 10-6 per year. The IAEA stipulates
0.3 mSv/year and 10-5 per year (IAEA, in prep. f ). It
was concluded that when comparing the approaches
in different countries not only the different numerical
criteria need to be considered, but also the philoso-
phy and societal consensus that determine what ac-
ceptable consequences are and what not. However,
it was also concluded that these variations do not
mean less adequate protection in some countries,
but rather differing desired levels of condence in
the ensuing safety. In fact, the effect of a repository
would not be detectable statistically even in the most
exposed critical group for any of these constraints.
Radiation protection principles have seen a sig-
nicant evolution over the past decades, with
various general ethical notions, such as intergen-
erational equity and protection of the environment,
being included. It is increasingly being realised that
a prescriptive approach focusing on one specic
numerical value for one exposure model does not
necessarily provide optimal protection under all
circumstances and may result in quite high societal
costs without entailing adequate benets. Radiation
protection, as all other human activities, has to oper-
ate in a socio-economic context and certain trade-offs
may provide overall benets. However, for a number
of reasons, not the least political ones, this is only
slowly being acknowledged among regulators.
JRC Reference Report
24
As has been noted in OECD-NEA (2007d) and else-
where, the ethical dimension of radioactive waste
management choices in general and of geological
disposal in particular is gaining importance. Both,
international guidance and national regulations
increasingly adopt concepts and language, such
as ‘intergenerational equity’ or ‘no undue burden
to future generations’ that reect certain ethical
notions and programmes. The ‘Joint Convention’
(IAEA, 1997d) imposes in that way moral and legal
obligation onto the signatory and ratifying states.
The traditions of the approach to implementing
regulations in different Member States are quite
different. Some countries prefer a prescriptive ap-
proach, whereby a given target value, e.g. a dose
is set and the safety case must be constructed to
meet this target. Other countries prefer a collabora-
tive approach, whereby implementer and regulator
(and perhaps other stakeholders) work together to
arrive at a solution that is not only optimised with
respect to a specic regulatory target value.
The increasing importance of stepwise decision
making and of reversibility and retrievability are
changing the nature of repository design to a proc-
ess that itself may span several generations. This
poses difculties for the regulatory decision mak-
ing process and for the ability to maintain transpar-
ency (OECD-NEA, 2007d).
Policymakingandradiationprotection
Waste management in general and geological
disposal in particular operate within a policy
framework determined at a lever higher than
that of the technical regulator. At this policy level
fundamental decision are made, such as those on
the continued use of nuclear energy, reprocessing
vs. direct disposal of spent fuel, on disposal vs.
long-term storage and so forth. It is, however,
not so straightforward to draw a border between
national policy questions and regulatory matters.
The role and competencies of national technical
regulators can vary considerably, reecting the cul-
tural differences and traditions and evolved with
time (OECD-NEA, 2003f ). This has resulted in varying
radiation protection criteria and methods of demon-
strating compliance with regulations (OECD-NEA,
2004k,2005i). Indeed, the bases for approaching risk
and for setting these criteria vary as well (VARI, 2004).
A commonly accepted denition of what constitutes
‘safety’ and what constitutes ‘protection’ is still lack-
ing to date (OECD-NEA, 2007d). The authors of this
report concluded that is not possible to draw a picture
of an idealised, or even a typical, regulatory model for
the different countries. It is also interesting to review
OECD-NEA (2007f), which contains a discussion of
the current thoughts on the state and future develop-
ment of radiation protection that move away from the
paradigms of dose as main measure and away from
humans as the only species to be protected.
The development of safety cases iterates between
implementers and regulators. The implementers
act within a given regulatory framework, while on
the other hand the regulators have to take realities
and real-life constraints into consideration. Regu-
latory requirements must be practical. It must be
possible to demonstrate that the requirements are
met. At the same time, as science is progressing,
radiation protection and environmental legislation
is being further developed.
Regulating a geological repository involves judge-
ments on events and developments far into the
future. For this reason it does not only involve tech-
nical judgements, but also value judgements and
ethical considerations, even though regulatory
bodies might consider this outside their realm.
The NEA compiles a database on the respective
regulatoryframeworkintheirMemberStates.The
signatory states to the ‘Joint Convention’ (IAEA,
1997d) also have submitted information on the
regulatoryframeworktothesecretariat,theIAEA.
In their Net-Enabled Waste Management Data-
base (NEWMDB; http://www-newmdb.iaea.org/)
theIAEAcollectsin additiontoinformationabout
thewaste itself informationon how the waste is
managedandregulated.
Differingneedsofstakeholders
The three main groups of stakeholders in geologi-
cal disposal, namely the implementer, the regulator
and the general public (which is understood here
as an all inclusive term), have differing needs and
requirements for regulations.
The implementer needs clear and preferably quan-
titative guidelines by which the process and its
end product can be designed. In principle the im-
plementer would also prefer to have in place from
the outset a clear set of regulations, requirements
JRC Reference Report
25
and guidelines. However, as has been pointed out
at several places, regulating geological disposal is
in fact an ongoing process.
The regulator, in principle, would also prefer clear
and quantiable guidelines for which compliance
can be demonstrated easily. However, due to the
timescales involved compliance can only be dem-
onstrated for the operational phase of the reposi-
tory, while there is no guarantee that monitoring
to demonstrate compliance will be carried beyond
several generations. Regulators in general also
seem to prefer solutions involving (active) institu-
tional control and still seem to struggle somewhat
with the concept that there cannot be active ongo-
ing control to assure safety. For this reason, regula-
tors tend to require a reasonable demonstration of
connement, rather than that no harm is done to
humans and the environment.
The actual needs of the general public at any
time of the process are difcult to assess and,
hence, may be difcult to meet. Over the years
a number of tools to identify stakeholder con-
cerns have been developed and experience has
been gained with various techniques for involv-
ing the public in decision-making processes and
in addressing these concerns (e.g. OECD-NEA
2003e,2003k,2004e,2004f,2004m). Transparency
of the decision making and licensing process is an
overarching criterion. This transparency also needs
to extend to the bases of the criteria for decision
making (OECD-NEA 2003e,2004e,2004i).
Enablingregulators
Having regulations in place alone is not sufcient.
It must be assured that the regulatory bodies are
adequately equipped with competent and capable
staff. The regulatory and supporting activities,
such as independent research, must be adequate-
ly funded. The regulators must be given the nec-
essary executive powers or the competence to
invoke executive support from other government
bodies, if needed. In order to instil condence
among all stakeholders, the regulator must be in-
dependent. These points are also stipulated in Re-
quirement 1 of the draft IAEA Safety Requirements
for geological disposal (IAEA, in prep. f) and in the
‘Joint Convention’ (IAEA, 1997d). Regulators must
be continuously trained so that they are enabled
to judge and challenge proposals put forward by
the implementer.
Peer reviews of regulatory bodies and participa-
tion of regulators in internationalac tivities, such
as those organisedby theIAEA andthe NEAwill
helptokeepregulatorsattheforefrontofdevelop-
mentsandpointtofurtherenablingneeds.
Regulatorygapsandinconsistencies
The regulatory process for geological disposal has
been largely driven by radiation protection consid-
erations, but various radionuclides are also rel-
evant from a chemotoxicological point of view as
has been pointed out earlier. No international or
national legislation provides guidance on permissi-
ble environmental concentrations for radionuclides
other than uranium (in some countries) and radon.
Improved engineering design has resulted in the
predicted retention of the most important nuclides,
such as uranium and plutonium, with the effect
that now long-lived, more ‘exotic’ nuclides, such as
those of selenium, show up in performance assess-
ment calculations.
Much of the existing radiation protection guidance
and legislation was originally drafted for medical,
laboratory and industrial exposures to discrete and
directly controllable sources of radiation. Hence,
the traditional basic measure in radiation protec-
tion is dose. However, calculating a ‘dose’ requires
knowledge, or assumptions, about possible expo-
sure scenarios. The radiation protection commu-
nity has been very slow in accepting the fact that
humans live rather different lives in different parts
of the World and therefore would be subject to
rather different exposure scenarios given the same
environmental concentrations. Making predictions,
or even assumptions, about life-styles beyond a
few hundred years becomes rather speculative and
on the scale of millennia even meaningless. There-
fore, a consensus is developing (ICRP, 2000; IAEA,
2006a) that numerical criteria should only be used
as a reference or an indicator, rather than absolute
limits in a legal sense. It should also be noted that
the objective of radiation protection is not the ab-
solute prevention of harm, but rather the reduction
of the potential of harm to acceptable levels.
Regulators and implementers alike continue to
struggle with the phenomenon that the public may
be less inclined to accept high-consequence/low-
probability events than low-consequence/high-
probability events, though both may entail the
same risk. Regulators have been responding to this
JRC Reference Report
26
by prescribing different risk or target constraints.
Exposures to disperse sources of low concentra-
tion and over potentially very long periods of time
is a comparatively new challenge and guidance and
legislation is still being adapted.
Further, as OECD-NEA (2007d) points out, the
‘Joint Convention’ leaves a number of important
terms and concepts undened, for instance what
is exactly meant by ‘future generation’, which
leads to differing interpretations in different
Member States.
Not only do protection criteria and the methods of
demonstrating compliance differ from country to
country, but the bases for setting the criteria ap-
pear to vary as well. In fact, the difference may
even reect difference in fundamental protection
objectives. Within the NEA RWMC Regulators’ Fo-
rum ’Long Term Safety Criteria (LTSC) group the ini-
tial idea of arriving at a ‘collective opinion’ evolved
to one of fostering a common understanding of the
bases for regulation that countries have formulat-
ed or are adopting (OECD-NEA, 2007d). A number
of important contributing factors were identied.
Among them are
the complexity and non-uniformity of the de-•
cision making processes across nations,
a lack of consensus on how to characterise •
and measure protection in the distant future,
the range of institutions involved in decision •
making,
not fully worked-out fundamental ethical is-•
sues related to the nature of current society
obligations to the future, and, reecting all
of this,
international guidance that has been evolving •
with time and still is.
One of the goals of the IAEA has been to ensure
that radiation protection and subsidiary regula-
tions are in place in all of its Member States. This
is certainly now true in principle for the EU Member
States, where many of the newer members appear
to have followed the IAEA guidelines and recom-
mendations, while at the same time complying with
both, the IAEA (FAO et al., 1996) and the European
(EURATOM, 1996) Basic Safety Standards. Some
Member States have subject themselves to inter-
national peer review procedures of their respective
regulatory infrastructure.
Overalltheredoappeartobenosignicantregu-
latorygapsin MemberStates.However,thereare
differencesintheregulatoryapproaches.
Towardsacommonunderstanding
Though the regulatory approach might be differ-
ent in different Member States, it appears to be
important that some basic criteria and underly-
ing concepts are harmonised, for instance along
the lines of thought developed by the RWMC
(OECD-NEA, 1997c). Framing common ideas on
our obligations to future generations may be an
important conceptual and ethical issue to resolve
here. Otherwise such differences might raise con-
cern among stakeholders, who might consider
themselves less protected in one Member State
than in another. In the light of shared facilities
or services varying protection criteria might also
raise concerns over risk displacement, as opera-
tors might want to opt for solutions in countries
with less stringent regulations. However, there
will be limitations to harmonisation, as differing
approaches also reect national regulatory cul-
ture, values and technical differences in the Mem-
ber States’ programmes.
The need for an internationally harmonised ap-
proach to assessing safety cases has been recog-
nised by the regulatory authorities. At European
level the ‘European Pilot Study’ (BESNUS et al.,
2006; LACOSTE, 2007) and at wider international
level, the IAEA GEOSAF project have been initiat-
ed. In addition, a Working Party on Nuclear Safety
(WPNS) in the European Union is currently analys-
ing to what extent common approaches to waste
management are implemented by its Member
States. A preliminary conclusion from these efforts
is the observation that, while the regulatory frame-
work may differ considerably, the regulatory prac-
tices do much less so. The latter is certainly owed
to the intensive exchange between different regu-
latory authorities, implementers and international
organisations as facilitators.
Efforts to harmonise safety criteria in the industrial
aspects of the nuclear industry are somewhat more
advanced, as is evidenced by WENRA’s (http ://
www.wenra.org/) efforts (WENRA, 2006).
JRC Reference Report
27
The majority of EU regulators are represented in
internationalgroups,suchastheWPNSortheRW-
MC-Regulators’ Forum, which ensures, as it does
forthescienticcommunity,acomparablelevelof
understandinginallMemberStates.
Due to the wide variability in the regulatory ap-
proaches,itappearstobemoreefcienttodevelop
acommonunderstandingoftheseapproachesand
the underlying safety objectives, but to abstain
fromrecommendingauniedapproach.
RatherthantryingtounifyatEUlevelallregula-
tionspertainingtogeologicaldisposal,itmight
be also more efcient to ensure through some
international review process that these regula-
tions are adequate and have a common set of
safetyobjectives.
Additional references: IAEA (1999b,2001,2005b,in
prep. b), OECD-NEA (2000, 2002f)
5. The Safety Case
Conceptualoverview
Requirement 3 of the draft IAEA Safety Require-
ments for geological disposal stipulates that “The
operator shall carry out safety assessments and
develop a safety case, ...”. A ‘safety case’ may be
broadly dened as a structured presentation of the
evidence, analyses, and lines of reasoning related
to the long-term radiological safety of a proposed
or actual radioactive waste repository (OECD-NEA,
2004g). It aims to demonstrate that the repository
will function according to prescribed requirements
and to expectations over a range of conditions in-
cluding ones that are deemed unlikely or extreme.
The safety case will be the basis for licensing a re-
pository. Thus the safety case has to demonstrate
that all possible features, events and processes
(FEPs) that might be of relevance over the pre-
scribed time frame have been taken into account
(OECD-NEA, 2000a; MAZUREK et al. 2003) and that
adequate levels of protection are achieved (Require-
ment 13; IAEA, in prep. f). Moreover these FEPs have
to be understood quantitatively with a certain level
of condence in order to be able to demonstrate in
safety assessments that acceptance levels are met.
Establishing a safety case consists of three major
activities, namely the development of a conceptual
site model, collating site and process data to sup-
port the model, and making predictions about the
future development of the site using these data
and models. Considering and quantifying concep-
tual and data uncertainties is a vital element in this
process. The quantiable information will be com-
plemented by scientic reasoning and expert opin-
ion, thus providing multiple lines of evidence.
Many Member States face the difculty that the
regulatory framework from which the accept-
ance criteria are derived has to be developed
concurrently with the safety case (see also Sec-
tion 13). There is a good reason for this, as both
are informed by the same type of fundamental
research; as process and system understanding
improve, the regulatory framework as well as the
safety case are rened.
The NEA, together with the EC and the IAEA, organ-
ised in January 2007 an international symposium
(OECD-NEA, 2008c) that was aimed to be a stock-
taking exercise with respect to the development
of safety cases. It was noted in particular that key
evolutions over the past decade included:
Improved and structured documenta-•
tion to favour clarity and traceability of
argumentation;
argumentation that demonstrates the know-•
ledge base accumulated by the project;
the development of more sophisticated ana-•
lytical tools and databases,
the introduction of new conceptual tools, such •
as the concept of safety function, that embody
key aspects of performance of the geological
disposal system and from which internal re-
quirements can be developed that relate the
ability of the disposal system to full these
functions, thus making more transparent the
role of various components (and their syner-
gies) in the disposal concept;
JRC Reference Report
28
the utilisation of performance and safety in-•
dicators besides the traditional radiological
dose and risk indicators;
the open discussion – in the safety case itself •
– of extant issues of concern and the identi-
cation of a path forward to their resolution.
Natural systems are usually complex and often
‘chaotic’ and therefore difcult or even impossible
to predict in quantitative terms over extended time
scales. In order to capture possible outcomes, two
conceptually somewhat different approaches to de-
veloping a safety case are possible and have been
used around the World:
the range of possible realities is captured by a)
parameter variation in numerical models and
statistical sampling of the results; this is the
domain of probabilistic performance assess-
ment modelling. Alternatively,
no probabilistic performance modelling is b)
used, but a system of logical reasoning and
bounding of system performance parameters
is developed.
The actual approach chosen by the respective
waste management organisation depends on the
regulatory requirements. In practice often elements
of both approaches are combined into a stream of
multiple evidence.
The development of the fundamental concepts for a
safety case has been a truly international collabora-
tive effort and is largely independent of the host rock
to be chosen. The country specic differences arise
from the differing regulatory requirements. In ad-
dition to the two fundamental approaches outlined
above, the selected target measures may also dif-
fer. In some countries such measures may be doses
to particular critical groups, while in other countries
these may be uxes or concentrations of radionu-
clides in particular environmental compartments.
The concept of using doses alone to assess perform-
ance and safety far into the future is being increas-
ingly criticised, as it adds the additional uncertainty
of having to make assumptions about exposure sce-
narios for times far into the future. The history of
modern man (homo sapiens) goes back only about
200,000 years, therefore, it is not very likely that
in a million years from now there will be a human
species with feeding and other habits similar to
present-day man. Therefore, doses should only be
used as performance indicators and for comparison
of alternatives, but not as limits or targets. The last
observation also implies that a dose calculated for
a given repository system and evolution scenario
will not be the only criterion for accepting or reject-
ing a particular site and repository system. Further,
the decade-old paradigm that the environment will
be protected, if man is being protected has been
questioned and new guidelines for protecting the
environment and non-human species are being de-
veloped currently (OECD-NEA, 2007f).
The term ‘safety case’ (or equivalent wording) is
not used in all national regulatory frameworks.
Nevertheless, the internationally developed con-
cepts and criteria for safety cases are important
benchmarking tools. Whether and how safety
cases could be made comparable has been exten-
sively discussed in international fora. Various NEA
reports (e.g. OECD-NEA, 2007d) have given very
strong cautions that the results of different safety
cases cannot be compared directly due to the many
ways in which they differ – the criteria, the sites,
the range of scenarios considered, the statistical
measured used to judge compliance, the various
assumptions and stylisations, etc. However, it may
be valuable in the European context for the purpose
of comparison and condence building to develop
a translation scheme for the results from different
types of safety cases. Putting a specic national
safety cases into an international context would
certainly help to increase local condence and ac-
ceptance. Considering the already well-developed
regulatory framework and repository programmes
in several Member States, such procedure certainly
would be preferable over harmonisation. Interna-
tional efforts, such as the ‘European Pilot Study’
(BESNUS et al., 2006; LACOSTE, 2007) and at wider
international level the GEOSAF project are aiming
to prepare the ground for more harmonisation. The
NEA INTESC initiative (http://www.nea.fr/html/
rwm/igsc_coreactivities.html#intesc) is aimed at
assessing recent experience in developing safety
cases and to identify areas of consensus and diver-
gence, as well as ongoing challenges and emerging
trends, by comparing the approaches and results
achieved in the various Member States.
The development of a safety case is an iterative and
recursive procedure that aims to optimise overall
safety, taking into account the natural situation,
engineering features and the applicable regula-
tory requirements. There may be several pathways
to safety and different mixes of safety functions
JRC Reference Report
29
that arrive at the same overall level of safety. For
instance, repositories to built in argillaceous or
salt formation can put less emphasis on the long-
term performance of waste forms, packages and
the engineered near-eld than a repository to built
in fractured hard-rock. Using, for instance, dose a
measure, different repository concepts in different
host rocks will achieve different levels of safety.
However, all currently investigated disposal con-
cepts are capable of achieving dose levels are be-
low current regulatory requirements.
NEAisundertakingareviewofsafetyassessment
methods and rst results are expected in 2009;
theprojectwillbe coordinatedwithPAMINA,and
onepossibleproductisajointOECD-NEA/ECbro-
chureon the topic. These issues will also be dis-
cussedinmoredetailin thecompanionreporton
theSafetyCase.
Additional references: IAEA (1988,1993,1997,1999
d,2000,2002,2003c2005a,2006,in press), OECD-
NEA (1997,1999,2001,2004d,2004g,2004h,2004m,
2005f,2006c,2007c)
Simplicationissues
For practical reasons numerical models that may
be used in probabilistic safety assessments have
to be based on rather simple mechanistic models.
For instance and as discussed above, these models
still employ unconditional retardation factors for
the radionuclide migration vector that are derived
from distribution coefcients (Kd-values), though
the conceptual problems and mechanistic limita-
tions of Kd-values are well recognised. It needs to
be quantitatively assessed for each case whether
and how simplifying assumptions will inuence the
outcome of performance assessment calculations.
It needs to be shown in particular that for a given
scenario the underlying assumptions are robust
and keep the overall model within a certain enve-
lope, meaning that a more mechanistic model could
change the magnitude of the result, but not its ba-
sic outcomes, such as calculated pathways.
TheprojectPAMINAwillhelptoclarifythepicture
onsimplicationissues.
Upscalingissues
Most natural processes are scale-dependent. Proc-
esses and parameter values derived from laboratory
experiments have to be extrapolated to eld condi-
tions (OECD-NEA, 1997b). Different processes may
be dominating at different scales. For instance, in a
small rock sample transport processes may governed
by the porosity, while on the eld scale transport in
the same material may be dominated by fractures
that do not occur in the small sample. Drawing conclu-
sions from permeability measurements on the small
sample to the host rock bulk permeability would lead
to erroneous results. The upscaling issue is closely
related to the question of heterogeneity. Given the
limitations in resources, accessibility and others,
heterogeneous systems cannot be investigated in
all details, but their behaviour must be inferred us-
ing statistical techniques. Respectivesamplingstrat-
egiesand required samplingdensitiesas wellas a
quantitativeassessmentoftheassociateduncertain-
ties continues to be the subject of research within
andoutsideoftheradioactivewastecommunity.
Many practical questions around repository design,
construction and operation cannot be resolved on a
theoretical basis, but practical experience is need-
ed (IAEA, 2001d). For this reasons several Mem-
ber States and other countries around the World
have constructed Underground Research Facilities
(URFs) or have converted existing mines for this
purpose. These research facilities allow to conrm
in situ concepts and data that have been developed
on small sample recovered from drill cores for in-
stance. The facilities are also used to test various
emplacement design etc. using non-radioactive
mock-ups. Examples include the simulation of
decay heat-loads by electric heaters. At some stage
the waste emplacement and sealing techniques
will be also tested in situ using inactive compo-
nents. Realising that for the various groups of host
rocks synergies between the different research
undertakings can be generated and with a view to
increase the utilisation of URFs by opening them up
to partners with less advanced programmes, the
IAEA initiated a Network of Centres of Excellence
(http://www.iaea.org/OurWork/ST/NE/NEFW/
wts_network.html). Theobjectivesofthenetwork
aretoencouragethetransferand preservationof
knowledgeandtechnologies,toworkonsolutions
forMemberStatescurrentlywithoutURFs,tosup-
plementnationaleffortsandpromotepubliccon-
denceinwastedisposalschemes,andtocontribute
totheresolutionofkeytechnicalissues.
JRC Reference Report
30
Theissueoftimescales
As predictions about the post closure-future of the
repository are to be made, two questions about
timescales automatically arise, namely for what pe-
riod of time do we need to make such predictions
and over what period of time can we make predic-
tions with some condence (IAEA, 2000a). Thede-
cisionforwhichtimehorizonpredictionshavetobe
madeislargelyanethicalone,thoughitisinformed
byscienticresearchintooverallfuturesitedevel-
opmentandassociatedprobabilities. For instance,
a possible criterion is the development of radio-
toxicity of the high-level waste or spent fuel. It will
take in the order of 100,000 years to reach natural
levels. Implementers will have to show compliance
with respective regulatory requirements, which
are ultimately based on ethical considerations. In
particular the NEA has been discussing this issue
(OECD-NEA 2004j, 2006i), but it is concluded that
the ultimate decision rests with the national regu-
lators. The issue is closely linked with that of con-
dence building. Scientist will have to successfully
communicate to stakeholders their condence in
their own predictions of site development.
Processrelevance
It is important that all relevant features, events and
processes (FEPs) that might affect the safety case
are adequately captured. The basis for this is a
catalogue of FEPs. Which processes from the cata-
logue of FEPs will be relevant is also closely related
to the questions of scale and simplications made.
The NEA developed such a catalogue on a generic
basis (OECD-NEA, 2000a) and recently updated it.
Such catalogue will be universally applicable to all
types of host rocks in all countries, though not all
actual FEPs are expected to occur in any one coun-
try. ThecatalogueofFEPswillserveasbenchmark
for testing national safety cases for relevance
and completeness. The use of ‘safety functions’
is emerging as an important tool to asses the rel-
evance of various processes and to dene key sce-
narios to be assessed.
If the output variability of a system, such as the
results of transport calculations, can be explained
with a reasoned variability of input parameters at
a given scale level, then processes at a more de-
tailed level would not need to be investigated, if
they do not result in a change in the variability of
the output at the higher level. Again the project
PAMINA (http://www.ip-pamina.eu/)is currently
investigating such issues and a cohesive strategy
for dealing with this aspect will be developed at
European level.
Performanceindicators
The traditionally used overall safety and perform-
ance indicator is dose. Dose, however, depends on
the scenario and receptor chosen, the evolution of
which over large timescales is highly uncertain. In
recent years this concept has been criticised for be-
ing not very robust and because it may not neces-
sarily protect species other than humans (ht tp ://
www.nea.fr/html/rwm/safety_case/). More direct
and exposure scenario independent measures are
provided by radionuclide concentrations in envi-
ronmental compartments or respective uxes of
radionuclides. The latter could also be compared
with natural (geochemical) uxes of comparable
elements. The project PAMINA is currently critically
reviewing the complex of performance indicators
(BECKER & WOLF, 2008).
For certain radionuclides and depending on their
concentration not radiation dose but chemotoxic-
ity can be of concern. Except for uranium in some
countries, there are no regulatory standards for
radionuclide concentrations in environmental com-
partments. Therefore, no performance indicators
can be built currently on this basis. This may re-
quiresomeactiononEUlevel.
Conceptualandparameteruncertainty
Each safety case will have a range of different
uncertainties associated with it. Some of the un-
certainties are reducible, e.g. the magnitude and
distribution of permeabilities, while others es-
sentially are not reducible, such as the future de-
velopment of the climate. Reducibility is bounded
by numerous considerations, such as economical
feasibility, the desire not to disturb the host rock
in question, or practicability of obtaining data. In
addition, there remains always a certain level of
uncertainty over whether the chosen conceptual
models are adequate and sufcient.
Thus, it will not be possible to investigate in every
detail a repository site for reasons of limited re-
sources and in order not to disturb the natural sys-
tem unduly. It will also not be possible to quantify
JRC Reference Report
31
in 3-D space all features and processes that may
inuence repository performance and develop-
ment over time. Therefore, the conceptual model
for the system as well as its parameterisation has
a certain amount of uncertainty associated with it.
Quantitative methods to describe system variabil-
ity (OECD-NEA, 1998) and to decide on what level
of condence is needed for an acceptable safety
case are required. Undue safety margins can be
very costly.
These uncertainties impact on the safety case in
a variety of ways. It is important to quantify this
impact in order to ensure that the system per-
formance remains within the expected limit for all
interactions of the system components and for all
states of the system parameters. It may be noted
that propagation of uncertainties is likely to result
in ‘variant explosion’, which is usually contained by
expert judgement.
Current internationally sponsored research aims
to minimise the range of uncertainties, to capture
them quantitatively and to develop strategies to
handle them and to facilitate regulatory decision
making (IAEA, 1997c; OECD-NEA, 2005f). This
research includes the activities under PAMINA
(http://www.ip-pamina.eu/) and work sponsored
by the NEA. Hopefully, this work will result in
greater condence that uncertainties have been
adequatelycaptured.
Themanagementofthesafetycase
Much of the current work around safety cases is
concerned with the management of its develop-
ment. The scientic communities that develop the
safety case as such and its modelling tools are
different from the communities that develop the
supporting scientic process and materials knowl-
edge. Strategies and mechanisms have to be put
into place that ensure that all the available (geo-)
scientic knowledge is utilised in developing the
safety case. This includes quantitative as well as
qualitative information. The information has to be
utilised in a structured way so that individual ele-
ments of information are given due weight and to
avoid bias. Conversely, knowledge gaps identied
from the perspective of the safety case have to be
translated into research programmes. The AMIGO
series workshops (OECD-NEA, 2007e), for instance,
is intended to sample Member States practice and
experience in this particular area. The workshops
are organised in the context of the NEA task group
on Integration Group for the Safety Case (IGSC). In
the interest of condence building among stake-
holders, harmonised guidelines to the manage-
ment of safety cases and harmonised objectives
maybedesirable.
Emergingissues
This term originates in the engineering and project
management eld, where it refers to the process
that is designed to ensure that the best technical
solution is selected and implemented. The process-
es formalises technology selection according to a
predened set of criteria. The purpose is to ensure
that e.g. technology selection is need driven, rather
than vendor driven.
As the concept of BAT is also being referred to in
the Directive on Integrated Pollution Prevention
and Control (CEU, 1996) some cross-reference be-
tween this Directive and regulations for geological
disposal of radioactive waste might be needed.
One could argue, however, that the whole process
of developing a safety case together with the feed-
back into repository design in fact constitutes a
process to select BATs, though not the same termi-
nology is being used. Implicitly, the concept of BAT
may also be present in ICRP Publication 81 (ICRP,
2000). Recently the NEA Radioactive Waste Man-
agement Committee’s Regulators’ Forum has taken
up the subject and produced a rst review of perti-
nent literature (OECD-NEA, 2008b).
Inorder to put safety cases into perspective,it
maybeworthwhiletoexamineandcompareBAT
selection processes applied to other environ-
mental projects. This might also contribute to
condencebuilding.
There are, however, a number of conceptual ques-
tions around BAT. For instance, how is it dened
what constitutes a ‘best’ technology and how is
‘availability’ dened ? In the past this has led to
exaggerated demands by certain groups of stake-
holders. For this reason in some countries the BAT
concept has been replaced by the BPO (Best Practi-
cal Option) concept. This in turn leads to a discus-
sion of what is to be considered ‘practical’. In all
cases there will be elements of judgement that are
JRC Reference Report
32
driven by budgetary constraints as well as societal
negotiations on acceptability.
It should be noted that some countries that origi-
nally championed this approach, which was bor-
rowed from the well-established construction
engineering realm, are now backing away from the
use classical BAT/BPO concepts in emerging elds
such as radioactive waste disposal. However, as re-
lying on numerical performance indicators is also
being questioned considering the long timescales
involved, procedures are being developed that in-
tend to demonstrate that sound scientic and engi-
neering principles have been applied.
Other parameter optimisation concepts and poli-
cies borrowed from adjacent elds of science and
industry include ALARA (As Low As Reasonably
Achievable), which suffers from similar quantica-
tion issues as BAT and, hence, may not offer any
advantages over the processes and criteria used in
developing safety cases.
In the context of radiation protection this term re-
fers to a very specic process of judging various
costs and benets that should lead to a minimisa-
tion of exposure while not resulting in other soci-
etal detriments. In the wider context of geological
disposal this term may describe other features or
processes that are weighed against each other.
Thusoptimisationshould be an inherentresultof
thesafetycaseandtheprocess leadingtoitsde-
velopmentandimplementation.
As several national waste management pro-
grammes move closer to implementation, the as-
pect of operational safety becomes more relevant,
which is also reected in the 2009ff work pro-
gramme of e.g. the NEA IGSC. An operating repos-
itory will be a licensed nuclear facility and subject
to regulations in accordance with the Basic Safety
Standards of European Union (EURATOM, 1996)
and/or the IAEA (FAO et a l., 1996), The safety case
has to consider any feedback from operational
safety requirements into the design and layout of
a repository and its infrastructure. For instance,
the need for ventilation may worsen the effects of
the EDZ and therefore have repercussions on the
(long-term) performance of the repository. In the
same way the actual feasibility of construction
is to be considered. Withinthescope of generic
workplaceandindustrial safetystandardsthere
willbescopeforaEurope-wideharmonisationin
safety requirements for repository construction
andoperation.
6. Alternative Concepts
As has been recently emphasised by a collective
statement of the NEA RWMC (OECD-NEA, 2008d),
the preferred concept for the end point of radio-
active waste management is disposal in inland
deep geological formations (see also IAEA 2007f,
in prep. f). For many countries deep geological
disposal is the reference long-term management
solution. Nevertheless, it may be worthwhile in
the interest of condence building to periodically
re-assess the overall reasoning that lead to this
concept. In the past other concepts have been
discussed and investigated, such as now aban-
doned deep-sea seabed disposal. Deep borehole
disposal concepts are considered as a disposal
solution for certain types of wastes and may be
applicable in countries with very limited waste
generation (e.g. http://www.iaea.org/OurWork/
ST/NE/NEFW/documents/BOSS_Flyer.pdf). In-
deed, the NEA LTSC group has considered the
various options from different perspectives, rec-
ognising that isolation or dispersal strategies
over geological timescales are two end-members
of a strategy to re-distribute risks in time and
space (OECD-NEA, 2007d).
When scientic and societal knowledge have
grown,itmaybevaluabletore-visitdecisionsthat
havebeenmademainlyon the basis oftechnical
or political considerations. A step-wise decision
making approach during the implementation al-
lowstoaccommodatescientic,technicalandso-
cietaldevelopments.
JRC Reference Report
33
Closingtheissue
A repository project is likely to go ahead when all
groups of stakeholders – scientists, engineers,
operators/implementers, regulators, local admin-
istrators and the general public – are sufciently
condent that the repository will perform as de-
signed (OECD-NEA, 2002e). In other words, con-
dence needs to be established so that enough is
known to close the respective scientic and tech-
nical issues. There is no room here to enter into a
discussion of the epistemology of the science that
provides the basis for geological disposal. Much of
the controversies over geological disposal is cen-
tred on issues of truth, belief and trust. In prac-
tice, condence building is made up of various
elements, including quality management, outreach
and stakeholder interaction activities, manage-
ment of uncertainties, and monitoring. NEA’s Forum
on Stakeholder Condence (FSC) attempts to eluci-
date experience in condence building by “promot-
ing open discussion across the entire spectrum of
stakeholders in an atmosphere of trust and mutual
respect” (OECD-NEA, 2002f). Condence building
and providing multiple lines of evidence are essen-
tial components supporting safety cases.
Noclearmechanismsandcriteria exist todateto
determine quantitatively when an issue can be
closed. One also needs to distinguish between
site specic and generic aspects for which closure
needs to be sought. While in practice closure of ge-
neric issues is indicated by diminishing numbers of
new research proposals in the eld, this may not
be a sufcient criterion from a regulatory point of
view. Notwithstanding the epistemological dimen-
sions, in practice more quantitative guidelines can
be derived from probabilistic performance assess-
ment, whereby sensitivity analyses can demon-
strate whether a more precise knowledge would
improve the level of certainty in the safety case or
not. From a harmonisation and stakeholder trust
point of view, it would be desirable that the same
level of condence in scientic and technological
knowledge be achieved at international level. The
development of closing criteria and mechanisms is
one of the open issues for the NEA and will be ad-
dressed in 2009.
There are quantitative (geo)statistical methods
that can help to decide on the scope and extent
of site investigation needed (cf. PAMINA, ht tp ://
www.ip-pamina.eu/). However, there is also a con-
siderable amount of expert judgement involved as
to when a site is understood well enough. The use
of such non-quantitative methods and criteria is
being critically reviewed in the context of the IGSC
of the NEA. As each site is different, it would be dif-
cult to develop generally applicable closing crite-
ria. It is likely that closure of scientic issues will be
an iterative procedure whereby a case is presented
to the regulator/stakeholders once the implement-
er has enough condence in the scientic ndings
and technical solutions to proceed. If not accepted
by the regulator and/or stakeholders, a further
round of renement would be necessary. As far it
concerns site-specic properties, this process is
largely driven by the local regulatory and political
situation and, hence, may have limited scope for
harmonisation. Nevertheless guidance on how to
proceed in generic terms might be helpful for those
Member States that enter this phase. International
fora and research projects help to dene the state-
of-art of generic scientic issues and whether they
can be considered ‘closed’ for the purpose of the
safety case.
Condence is the result of trust in the implement-
ing organisation. Trust is built by providing the
assurance that the organisation is set up appropri-
ately to meet the requirements and to cover all the
relevant issues.
Theuseofnaturalanalogues
Natural (and anthropogenic) analogues have been
used for several decades in the development of
process understanding and to test conceptual and
process models (e.g. MILLER et al., 2000; IAEA
1989, 1999f, 2005c). More recently the potential
value of analogues for communicating with stake-
holders has been recognised.
While in the early years the use of natural
analogues concentrated on understanding and
parameterising processes as such, in more
recent years local and regional uxes of natural
(radioactive) geochemical constituents are being
used to deduct information on long-distance and
long-time migration phenomena (e.g. IAEA 2005a,
in press; HELLMUTH et al., 2007) and the long-term
behaviour of the geological systems in general.
For obvious reasons these phenomena are not
accessible in another way.
Nevertheless, detailed process analogues continue
to be studied under various programmes (e.g. IAEA
7. Confidence Building
JRC Reference Report
34
2005c). In these newer studies research focuses
inter alia on how well the analogues actually repre-
sent the processes for which they are chosen.
Itisexpectedthatanaloguestudieswillcontinue
throughout the implementation phase and there
willbevarioussynergieswithgenericmaterialux
andelementcyclingstudies.
Monitoring
There is some confusion in the usage of the term
‘monitoring’, which sometimes is applied to certain
phases of and activities under the site investigation
process. Indeed, it can be difcult to discern between
e.g. baseline environmental monitoring and site in-
vestigations, as the two would run concurrently.
Strictly speaking monitoring activities are carried
out in order to conrm that individual natural or en-
gineered system features or the system as a whole
behave as expected. Thus in the early phases of
implementation engineered systems may be moni-
tored for their performance, e.g. for settling or the
re-establishment of the natural hydraulic situation.
Monitoring is particularly carried out during those
phases of the implementation where there is still the
possibility for intervention (e.g. OECD-NEA, 2005n).
(Environmental) monitoring is also carried out as
a condence building measure with a view to dem-
onstrate to stakeholders that the disposal system
performs as expected, for instance to demonstrate
that no releases of radionuclides occur. While such
monitoring can be hardly justied on scientic
grounds, it can provide considerable reassurance
to the public.
Long-term monitoring does provide considerable
challenges for a variety of reasons: the probes have
to perform over very long periods of time under
very difcult conditions and without the possibil-
ity for maintenance or replacement. The necessary
connections from the surface to metering equip-
ment also must not provide preferential pathways
for radionuclides. In other words the monitoring in-
stallations must not compromise safety functions.
However, it forms an integral part of the licensing
procedure in some countries. For instance, Swit-
zerland plans to operate a special section of the
repository as underground research laboratory for
monitoring its performance.
In the context of phased repository implementation
and delayed closure, for instance in the interest of
retrievability, monitoring may become an important
management measure. Here it has to be shown that
the repository does not degrade prematurely and
that the safety functions are not compromised by
its prolonged open phase.
MonitoringhasalsobeenincludedinthecurrentFP7
callforproposals.It will be also addressed, to a de-
gree, in the upcoming NEA RWMC project on revers-
ibility and retrievability. In addition a possible NEA
IGSC workshop would focus on technological as-
pects and advancements in monitoring techniques.
Step-wisedecisionmaking
It becomes increasingly recognised that a step-wise
decision making process that allows for review and
modication or even reversal of previous decisions is
likely to increase condence into the overall project
(OECD-NEA, 2004i). A step-by-step approach is also
endorsed by the relevant draft IAEA Safety Require-
ments (Requirement 12; IAEA, in prep. f ). While a
step-wise approach has several benets for both im-
plementer and regulator, as it reduces the reliance
on strict compliance with protection criteria at each
step, it has also been accused of a sneaking approach
to implementation without overall assurance of com-
pliance, as in practice certain decisions are difcult
to revert. Overall, a step-wise approach, however,
will make the complex implementation process more
tractable and therefore more transparent. Similar
approaches are current practice in licensing complex
projects, such as nuclear power stations. It should be
noted that still a clear vision of the process, a ‘road
map’, is needed right from the beginning.
A stepwise decision making process that can
span several generations may be also seen in
the ethical context of intergenerational equity.
Astep-by-stepapproachallowssucceedinggen-
erations to modify decisions according totheir
expectations and needs, thus not prejudicing
theirfreedomofchoice.
Continuingresearch
The notion that an issue can be closed for the pur-
poses of building a safety case leading to a license
application does not necessarily mean that re-
search on this particular issue will stop completely.
JRC Reference Report
35
It is just an indication that there is sufcient con-
dence to proceed. As science continues to develop
in related and adjacent areas, an issue may need
to be revisited taking into account these new sci-
entic insights. This revision will help to decide,
whether there is still enough condence to further
proceed with implementation in the chosen way,
or whether the issue needs to be reopened. Thus
continuing research in particular areas that have
been designated as ‘closed’ is not a sign of lack
ofunderstandingor condence, butrather a con-
dencebuilding measure. This messageneedsto
beconveyedto stakeholders(OECD-NEA, 1999a)
Continuing research also ensures that at any one
time the best available technical solution is chosen
and helps to increase safety margins by reducing
uncertainties. Furthermore, continuing research
in all relevant areas is necessary to train new gen-
erations of scientists, who will be working on the
safety cases in decades to come.
8. Knowledge Management
Knowledge management has become a fashionable
term, but it lacks a clear denition. It appears that
three distinct, but related processes are covered by
this term: rst, the maintenance and preservation
of knowledge within a particular organisation, i.e.
corporate knowledge; secondly, preservation of
scientic knowledge about processes and phenom-
ena in general, with a view to prevent ‘re-inventing
wheels’; lastly, the passing on of information about
a specic repository to ‘future’ generations.
The issue of how knowledge about a repository
site might (need to) be communicated to future
generations has been debated in various fora
extensively, but no nal conclusions on the best
way forward have been drawn. There are numerous
examples from thousands of years of human history
where people have left to posterity written or
symbolic messages, but now we often cannot read
them anymore or do not understand their meaning.
Even in the case of symbols the effectiveness is
rather questionable – who understands all the
pictograms (e.g. for ‘Exit’, ‘Elevator’ and so on)
that are so fashionable today? The same symbol
may have different meanings in different cultures.
All this does not instil a great deal of condence in
our capability to transfer knowledge intentionally
beyond a few centuries and across signicant
cultural borders. Semiotics will have to go a long
way to arrive at messages and symbols that are
universally understood. An emerging and important
way to preserve the knowledge about a site is by
building an active and durable relationship between
it and the hosting community (OECD-NEA 2007b;
MAYS & PE SCATORE, 2007).
Scientic knowledge appears to have a life cycle of
around 10 years, when issues tend to be revisited.
Driving force frequently is the rate of innovation in
supporting technologies, for instance analytical
techniques. Another driving force not to be ignored
is the cycle of rejuvenation in academia. Thus we
currently see signicant numbers of researcher,
who have driven the programmes over the past
three decades, leave the eld to retire, and at the
same time scientic subject are being re-opened by
younger generations. The problem of diminishing
expertise is probably more acute in nuclear engi-
neering and in waste treatment technology than in
research into near- and far-eld processes. In latter
areas a strong cross-linking with the generic geo-
and materials science community can be observed
so that there is likely to be always a sufciently
large pool of expertise and knowledge.
Maintaining and preserving corporate knowledge
can become an issue, if the time of active repository
operation would be extended beyond a few decades
perhaps (IAEA, 2007b). This type of knowledge
preservation is not unique to nuclear waste man-
agement organisations. A variety of strategies have
been developed for other industries that would be
applicable in the present context. The concerns of
knowledge management in the nuclear industry have
been highlighted by a recent conference organised
by the IAEA in conjunction with other major players
in the eld (http://www-pub.iaea.org/MTCD/Meet-
ings/Announcements.asp?ConfID=153).
Additional references: IAEA (2001c, in prep c).
JRC Reference Report
36
Retrievability,reversibility
andlong-termstorage
The draft IAEA Safety Requirements (IAEA, in
prep. f) state that “Disposal refers to the em-
placement of radioactive waste ... withno inten-
tionofretrievingthewaste” (original emphasis).
Recent discussions arising from considerations
that range from resources conservation and re-
utilisation concerns to concerns over our current
ability to ensure long-term safety have started to
question this paradigm (e.g. OECD-NEA, 2001e).
However, the draft Safety Requirements insist
that “No relaxation of safety standards or require-
ments could be allowed on the grounds that waste
retrieval may be possible or facilitated by a par-
ticular provision. It would have to be assured that
any such provision would not have an unaccept-
able adverse effect on safety or performance”.
Though not necessarily linked conceptually, the
terms retrievability and reversibility are often
mentioned together. Retrievability refers to tech-
nical and management measures that would al-
low to retrieve waste packages that have already
been emplaced in a repository and possibly back-
lled (IAEA, 2001a, in prep. g). Conversely, revers-
ibility refers to measures and designs that ensure
that each step of repository implementation can
be retraced and different decisions taken. Thus
reversibility may be an enabling element in step-
wise decision making. There are various technical
and management as well as political reasons why
these two concepts have been brought onto the
agenda, but the discussion of which is beyond
the scope of the present report. The paradigm of
‘stepwise decision making and implementation’
was developed to reconcile some of the underly-
ing concerns. The safety and sustainability of de-
laying disposal beyond operational needs is still
being debated (IAEA, 2002b,2003f,2006d). NEA’s
RWMC strongly advised against undue delays
(OECD-NEA, 2008d) and the NEA plans to exam-
ine strategic and technical aspects of reversibility
and retrievability.
These new demands and concepts can have po-
tentially fundamental impacts on the safety case
and repository design (IAEA, in prep. g). Most of
the original concepts for geological disposal as-
sumed more or less tacitly a comparatively short
operational phase between the actual construc-
tion of a repository and its nal closure; at least
the lled parts of a repository would be backlled
and sealed as soon as possible. A repository de-
signed for (easy) retrievability may in fact consti-
tute an underground long-term storage facility.
This can have a number of implications for the
system performance and needs to be considered
in the safety case. Itisimportantthatthesystem
isdesignedinawaythatboth,retrievabilityand
reversibilityoptionsdonotcompromiseareposi-
tory’slong-termsafety. It may be noted that the
waste can be always retrieved by ‘mining’ tech-
niques, albeit at signicant cost and possibly risk
to (underground) workers.
Advancedfuelcyclesandpartitioning
&transmutation
Reactor systems and fuel cycles are under con-
tinuous development and new systems may entail
wastes and hence waste forms different from those
that arise from current nuclear energy systems. Re-
processing, partitioning and transmutation change
the type and the amount of wastes that will have to be
disposed of as well as the associated thermal load-
ing (IAEA, 2004a, OECD-NEA, 2003a,2005a,2006j;
EC project RED-IMPACT, http://www.red-impact.
proj.kth.se/). This can have effects on the layout
and operation of a repository. There is a certain in-
clination to adopt a delayed approach/long-term
storage and/or options of retrievability in order to
keep waste management options open so that one
may eventually benet from P&T or to accommo-
date wastes from new fuel cycles. However,these
developmentsshouldnotbeen usedasanexcuse
to delay implementation of waste management
systemswithgeologicaldisposalastheend-point
forresidualwastes(OECD-NEA, 2008d).
9. Other issues
JRC Reference Report
37
Governance is the process whereby societies or or-
ganizations make important decisions, determine
whom they involve and how they render account
(PLUMTRE, 2006). An European Commission White
Paper dened good governance as characterised
by excellence, independence, transparency, par-
ticipation and accountability (CEC, 2001).
A gradual shift from a purely technical to a socio-
technical framing of the radioactive waste issue
can be observed over the past decades (e.g. BERG-
MANS et al., 2008). Major crises and events seem
to lead to cross-national reactions, but it is striking
that similar crises in RWM emerge in several coun-
tries in spite of international exchange of informa-
tion and experience.
The importance of governance issues for the over-
all implementation process is reected by a variety
of past and current (http://www.radwastegovern-
ance.eu/) projects that aim to elucidate the soci-
etal processes and to improve interaction between
all stakeholders concerned:
TRUSTNET
http://www.trustnetinaction.
com/
COWAM http://www.cowam.org/
RISCOM II http://www.karinta-konsult.se/
RISCOM.htm
RISKGOV http://www.riskgov.com/
CETRAD http://www.grc.cf.ac.uk/cetrad/
OBRA http://www.obraproject.eu/
ARGONA http://www.argonaproject.eu/
CIP http://www.cowam.com/spip.
php?rubrique28)
CARL http://www.carl-research.org/
It is interesting to note in this context that little in-
teraction between the natural science and social
science communities has taken place in the past.
Their main interface indeed has become the devel-
opment of the safety case. Some activities, such as
the Forum on Stakeholder Condence (FSC; ht tp ://
www.nea.fr/html/rwm/fsc.html) of the OECD-
NEA feed directly into the process of developing
the bases for safety cases (OECD-NEA, 2002f ).
COWAM in Practice (CIP; http://www.cowam.com/
spip.php?rubrique28) brings together stakehold-
ers from various horizons to perform collaborative
research in ve European countries, while ARGONA
investigates how approaches of transparency and
deliberation relate to each other and also how they
relate to the political system in which decisions are
ultimately taken. The project aims to study the role
that is played by mediators who facilitate public
engagement with nuclear waste management is-
sues. Furthermore, the project investigates how
well risk communication can be organized taking
cultural aspects and different arenas of discourse
into account.
Overalltheseprojectsindicatethatcertainlessons
havebeenlearnt in the largercontextof radioac-
tive waste management. It is now widely under-
stoodthatappropriategovernanceprocesseshave
to be put in place so that desired nal solutions
inradioactivewastemanagementcan be brought
closertoimplementation.
Additional references: IAEA (2002c), OECD-NEA
(2000,2002c-e,2003e,2003g,2003i-k, 2004a-b,
2004e-f,2004l-m,2005e,2005m,2006f-g, 2007b)
VARI & PESCATORE (2007).
10. Governance
It can be observed that a certain level of maturity
has been reached in many scientic and technical
areas relevant to geological disposal. The term
maturity means that those features, events and
processes that are likely to be of importance have
been identied. Maturity does not mean that all of
these FEPs can now be sufciently parameterised.
Therefore, research continues and has to continue
for some time. By its very nature, research is curi-
osity driven, but at the same time reections are
undertaken on what we really need to know at what
level of detail or precision. Such reections and
quantitative assessments are the subject of, for
instance, the PAMINA project. It is envisaged that
the results from this project will provide guidance
on when we can proceed to actual implementation
with sufcient technical and scientic condence.
The close scientic co-operation on a European
and indeed world level ensures that all waste
management programmes can draw on up-to-date
scientic knowledge. An added benet is that sci-
entic work contributing to national waste disposal
11. Conclusions and Recommendations
JRC Reference Report
38
programmes and that is published in scientic
journals is automatically subject to a peer review
process.
Overall,itappearsthatourscienticunder-
standingofmostprocessesrelevanttogeo-
logical disposal is developedwell enough
to proceed with implementation in a step-
wisefashion.
Scientic co-operation, e.g. through the
Framework Programmes, ensures a Europe-
wide harmonised level of scientic under-
standing.Suchco-operationshouldcontinue
tobesupported.
Given the conceptual and scientic maturity of geo-
logical disposal in principle, it would appear to be
important to proceed to construction in those Mem-
ber States that have sufciently advanced the site
selection programme. This step is needed to test in
practice the paradigm of step-wise decision mak-
ing. At the same time it allows the real-scale testing
of the various scientic and technical hypotheses
and proposed technologies.
Arealexamplewilldemonstratethat imple-
mentation of geological disposal is feasi-
ble. International support to national pro-
grammesthat are faradvancedare likelyto
haveEurope-widespin-offbenets.
For less advanced Member States and for
thosewithmorelimitedresourcesitwouldbe
benecialtosupportthedevelopmentofjoint
solutions,eitherintheformofsharedreposi-
toriesorintheformofsharingtechnology.
The key element in moving towards implementation
is the development of safety cases. A safety case is
a structured presentation of the evidence, analyses,
and lines of reasoning related to the long-term
radiological safety of a radioactive waste repository.
Intheinterestofcondencebuildinginthe
processassuchandamongstakeholders,a
harmonisedstrategytothemanagementof
safety cases would be desirable. Support
to the various harmonisation initiatives
shouldcontinue.
An important element in condence building is
interaction with stakeholders. Owing to major
set-backs in some Member States on the road to
implementation, the importance of involving stake-
holders in an effective way has been recognised.
The objectives and means of effective stakeholder
involvement are reasonably well-established for at
least some socio-cultural contexts. However, cer-
tain scientic concepts are intrinsically difcult to
communicate, most notably the concepts of prob-
ability and risk. As the Berne Conference (http ://
www.icgr2007.org/) and the NEA RWMC (OECD-
NEA, 2008d) concluded, it is important and worth-
while to take the time necessary for an inclusive
and rigorous process of stakeholder involvement.
Both, the EC and the NEA are addressing this deci-
sive issue explicitly. Within cultural limits, it seems
to be important that the same concepts of govern-
ance be applied throughout the EU.
The awareness of the need to involve all
stakeholders in the decision making proc-
essestowardsimplementationof geological
disposalisnowhighthroughoutEurope.
Experienceonhowtoinvolvestakeholdersin
practiceisstillbeingbuiltup.
Designandoperationalrequirements(suchas
e.g.retrievabilityoraccessformonitoring)in-
troducedthroughthepublicparticipationproc-
essmaynotcompromise(long-term)safety.
The regulator has the task to balance the needs and
interests of the public and the implementers. The
main objective of regulations is the protection of hu-
mans and of the environment from potential adverse
effects ensuing from the chosen nuclear waste man-
agement solution. The ultima ratio in regulation is
the respective national law, which has to be in place
before any implementation can take place. A har-
monised European regulatory framework could be
of some advantage, but would be difcult to bring
about, considering the diverse regulatory ‘cultures’
and that some Member State already have national
regulations in place. Re-opening this process would
certainly set back some national programmes and
entail considerable expenditure.
Mechanismstodemonstratethatregulatory
objectivesinthedifferentMemberStatesare
comparablewillhelptoincreasecondence
among all parties concerned. Respective
Europe- and world-wide initiatives should
besupported.
JRC Reference Report
39
Mechanisms to demonstrate that Member
States’ regulationsprovide comparable pro-
tectionmightbeamoreefcientwayforward
thanfullyharmonisedoruniedregulations.
One aspect of concern can be the question wheth-
er regulators in Member States are actually ready
and capable to handle license applications. The
application review process requires that adequate
numbers of staff with an appropriate training are
available. Enabling and resourcing regulators is
likely to become an important task in the near
future in some Member States and could become
an obstacle to implementation, if not addressed
in due time.
The European Commission needs to ensure
that National regulators are capableto per-
formtheneededtasks.Jointprogrammesbe-
tweentheinternational organisationsaimed
at enabling the regulators in less advanced
countries would help to reach an adequate
levelofpreparednessinallMemberStates.
There is a considerable overlap between the con-
stituencies of the EC, NEA and IAEA. All EU and NEA
Member States are members of the IAEA, while the
majority of EU Member States are in turn also mem-
bers of the NEA. While for this reason an overlap in
the interests and working areas between the three
organisations can be expected, in practice the man-
date and working practices are quite different.
The EC, unlike the other two organisations, has
legislative powers (right of initiative) and EU ‘Di-
rectives’ have to be implemented in national leg-
islation. In its role as defender of the Treaties, the
EC has executive powers that can be exercised
e.g. via sanctions. The EC also has considerable
nancial means that can be used to fund targeted
research. Many important nuclear waste disposal
R&D projects have been co-funded over the past
decades by the Euratom Framework Programmes.
The IAEA is formulating technical guidance and reg-
ulatory guidance based on consensus. In addition,
Member States may subject themselves voluntarily
to binding agreements, such as the ‘Joint Conven-
tion’ (IAEA, 1997d) for which the IAEA provides the
secretariat. IAEA guidance is frequently used to in-
form and in drafting national guidance and (bind-
ing) legislation. However, the IAEA does not have
executive powers and non-compliance can only be
sanctioned by publicly exposing the culprit. The
IAEA has limited amounts of funds that can be used
to stimulate research in particular areas for instance
in the form of ‘Co-ordinated Research Projects’ and
to provide seed money for joint projects funded by
national means.
The NEA provides more of a forum of exchange and
a ‘think tank’. It does not issue documents that are
intended to inform or draft national regulation or
guidance documents, but rather documents that
intend to conceptualise the issues under discus-
sion. These issues can be of scientic, technical,
governance or regulatory nature. The NEA does not
have any research budget of its own, but solicits
voluntary contributions from interested parties in
member states to fund targeted research.
ThusthedefactorolesoftheECcanbeseen
asproviding the policy frameworkand R&D
funding,oftheIAEA as providingregulatory
andtechnologicalguidance,andoftheNEAas
compilingandanalysingnationalexperiences
intermsofstrategicprinciplesandscientic
andsocietalaspectsofimplementation.
JRC Reference Report
40
13. References
A number of individuals kindly reviewed the draft for this document and provided their comments; these
include G. Bruno (DG-TREN), S. Webster (DG-RTD), E. Forinash and C. Mays (OECD-NEA), as well as N.
Taylor and R. Burcl (IE, DG-JRC).
12. Acknowledgements
: Below a rather comprehensive list of reports produced by the relevant international organisations
is given. It lists additional reports to those cited in the above text.
ANDERSSON, K. et al. (2004): Transparency and Public Participation in Radioactive Waste Management.
RISCOM II Final report.- SKI Report : 124 p., Stockholm.
BECKER, D.-A., WOLF, J. (2008): General Concepts of Supporting the Safety Case by Means of Safety and
Performance Indicators.- PAMINA, Performance Assessment Methodologies in Application to Guide
the Development of the Safety Case (Contract Number: FP6-036404), Deliverable D-No. 3.4.1, 22 p.,
http://www.ip-pamina.eu/downloads/pamina3.4.1.pdf
BERGMANS, A., ELAM, M., KOS, D., POLI
Č
, M., SIMMONS, P., SUNDQVIST, G., WALLS, J. (2008): Wanting the Un-
wanted: Effects of Public and Stakeholder Involvement in the Long-Term Management of Radioactive
Waste and the Siting of Repository Facilities. Final Report CARL Project.- 68 p., http://www.carl-
research.org/docs/20080222112500ZGYI.pdf
BESNUS, F., VIGFUSSON, J., SMITH, R., NYS, V., BRUNO, G., METCALF, P., RUIZ-LOPEZ, C., RUOKOLA, E., JENSEN, M.,
RÖHLIG, K. (2007): European pilot study on the regulatory review of the safety case for geological
disposal of radioactive waste.- EUROSAFE, Paris, 13-14 November 2007, http://www.eurosafe-forum.
org/products/data/5/pe_439_24_1_seminar2_02_2006_.pdf
BRUNO, J., BOSBACH, D., KULIK, D., NAVROTSKY, A. (2007): Chemical Thermodynamics of Solid Solutions of
Interest in Radioactive Waste Management.- Chemical Thermodynamics Series, 10: 267 p., Paris
(OECD-NEA).
COMMISSION OF THE EUROPEAN COMMUNITIES (2001): European Governance. A White Paper.- COM(2001)
428 nal, 35 p., Luxembourg.
EUR ATOM (1996): Directive 96/29/EURATOM of 13 May 1996 laying down basic safety standards for the
protection of the health of workers and the general public against the dangers arising from ionizing
radiation, European Commission, Luxembourg.
FALCK, W.E., READ, D., THOMAS, J.B. (1996): CHEMVAL2: Thermodynamic Database – Final Report.- CEC
Rep. EUR 16897EN: 164 p.
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS, INTERNATIONAL ATOMIC ENERGY AGENCY, IN-
TERNATIONAL LABOUR O RGANISATION, O ECD NUCLEAR E NERGY AGENCY, P AN A MERICAN HEALTH O RGANIZA-
TION, WORLD HEALTH O RGANIZATION (1996): International Basic Safety Standards for Protection Against
Ionizing Radiation and for the Safety of Radiation Sources.- Safety Series No. 115, IAEA, Vienna.
GRENTHE, I., PUIGDOMENECH, I. (Eds.) (1997): Modelling in Aquatic Chemistry.- OECD Publications, 724 pp.,
ISBN 92-64-15569-4, OECD-NEA, Paris.
JRC Reference Report
41
GRÜNDIG, M., RICHTER, M., KULENKAMPFF, J., SEESE, A. (2007): Studies of the Spatial Water Flow Distribution
and Colloid Transport in Crystalline Rock Core from Äspö with Positron Emission Tomography.- 2nd An-
nual Workshop Proceedings of the Integrated Project “Fundamental Processes of Radionuclide Migra-
tion” – 6th EC FP IP FUNMIG, SKB Technical Report TR-07-05: 223-229.
HELLMUTH, K.-H. et al. (2007): Geochemical Fluxes in the Geosphere: Quantitative Understanding by Iden-
tication and Verication of Processes.- 2nd Annual Workshop Proceedings of the Integrated Project
“Fundamental Processes of Radionuclide Migration” – 6th EC FP IP FUNMIG, SKB Technical Report
TR-07-05: 139-147.
HODGKINSON, D. (2007): Notes on Panel Discussion, 17th October 2007, NF-PRO Fourth Workshop,
Brussels.- unpublished.
HORSEMAN, S.T., HIGGO, J.J., ALEXANDER, J., HARRINGTON, J.F. (1996): Water, Gas and Solute Movement
Through Argillaceous Media.- 306 p., OECD-NEA, Paris.
INTERNATIONAL COMMISSION ON RADIATION PROTECTION (2000): Radiation Protection Recommendations as
Applied to the Disposal of Long-Lived Solid Radioactive Waste.- ICRP Publication 81.
INTERNATIONAL ATOMIC ENERGY AGENCY (1987): Materials Reliability in the Back End of the Nuclear Fuel
Cycle (Proceedings of a Technical Committee Meeting, Vienna, 2-5 September 1986).- IAEA-TEC-
DOC-421, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1987): In Situ Experiments for Disposal of Radioactive
Wastes in Deep Geological Formations (Report Prepared by a Group of Consultants).- IAEA-
TECDOC-446, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1987): Back End of the Nuclear Fuel Cycle: Strategies and Options,
Vienna, 11-15 May 1987.- Proceedings Series, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1988): Geological Data Integration Techniques (Proceedings of a
Technical Committee Meeting, Vienna, 13-17 October 1986).- IAEA-TECDOC-472.
INTERNATIONAL ATOMIC ENERGY AGENCY (1989): Natural Analogues in Performance Assessments for the
Disposal of Long Lived Radioactive Wastes.- IAEA Technical Reports Series No. 304, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1990a): Qualitative Acceptance Criteria for Radioactive Wastes to
be Disposed of in Deep Geological Formations.- IAEA-TECDOC-560, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1990b): Siting, Design and Construction of a Deep Geological Re-
pository for the Disposal of High Level and Alpha Bearing Wastes.- IAEA-TECDOC-563, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1991): Performance of High Level Waste Forms and Engineered
Barriers Under Repository Conditions (Final Report of a Co-ordinated Research Programme 1984-
1989).- IAEA-TECDOC-582, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1992): Performance of Engineered Barriers in Deep Geological
Repositories Details. Technical Reports Series No. 342, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1992): Geochemistry of Long Lived Transuranic Actinides and Fis-
sion Products.- IAEA-TECDOC-637, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1993): Report on Radioactive Waste Disposal Details. – Technical
Reports Series No. 349, Vienna.
JRC Reference Report
42
INTERNATIONAL ATOMIC ENERGY AGENCY (1993): Geological Disposal of Spent Fuel and High Level and Al-
pha Bearing Wastes Proceedings of an International Conference in Antwerp, Belgium, 19-23 October
1992.- Proceedings Series, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1994): Radioactive Waste Management Proles. Compilation of
Data from the Waste Management Data Base Number 2, April 1994.- IAEA-RWMP-V2, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1997a): Further Analysis of Extended Storage of Spent Fuel.- IAEA-
TECDOC-944, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1997b): Characterization of Radioactive Waste Forms and Pack-
ages. - Technical Reports Series No. 383, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1997c): Regulatory Decision Making in the Presence of Uncertainty
in the Context of the Disposal of Long Lived Radioactive Wastes.- IAEA-TECDOC-975, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1997d): Joint Convention on the Safety of Spent Fuel Management
and on the Safety of Radioactive Waste Management.- IAEA INFCIRC/546, Vienna, http://www-ns.
iaea.org/conventions/waste-jointconvention.htm
INTERNATIONAL ATOMIC ENERGY AGENCY (1999a): Hydrogeological Investigation of Sites for the Geological
Disposal of Radioactive Waste.- Technical Reports Series No. 391, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1999b): Quality Assurance within Regulatory Bodies.- IAEA-TEC-
DOC-1090, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1999c): Survey of Wet and Dry Spent Fuel Storage.- IAEA-TEC-
DOC-1100, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1999d): Review of the Factors Affecting the Selection and Imple-
mentation of Waste Management Technologies.- IAEA-TECDOC-1096, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1999e): Maintenance of Records for Radioactive Waste Disposal.-
IAEA-TECDOC-1097, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (1999f): Use of Natural Analogues to Support Radionuclide
Transport Models for Deep Geological Repositories for Long Lived Radioactive Wastes.- IAEA-TEC-
DOC-1109, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2000a): Extrapolation of Short Term Observations to Time Periods
Relevant to the Isolation of Long Lived Radioactive Waste.- IAEA-TECDOC-1177, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2000b): Radioactive Waste Management Proles - Number 3. A
Compilation of Data from the Waste Management Database.- IAEA-RWMP-V3, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2000c): Safety of radioactive waste management Córdoba, Spain,
Proceedings Series, STI/PUB/1094, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2001a): Retrievability of High Level Waste and Spent Nuclear Fuel
Proceedings of an International Seminar in Saltsjoebaden, Sweden, 24-27 October 1999.- IAEA-TEC-
DOC-1187, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2001b): Monitoring of Geological Repositories for High Level Ra-
dioactive Waste.- IAEA-TECDOC-1208, Vienna.
JRC Reference Report
43
INTERNATIONAL ATOMIC ENERGY AGENCY (2001c): Waste Inventory Record Keeping Systems (WIRKS) for the
Management and Disposal of Radioactive Waste.- IAEA-TECDOC-1222, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2001d): The Use of Scientic and Technical Results from Under-
ground Research Laboratory Investigations for the Geological Disposal of Radioactive Waste.- IAEA-
TECDOC-1243, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2001e): Training the Staff of the Regulatory Body for Nuclear Fa-
cilities: A Competency Framework.- IAEA-TECDOC-1254, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2001f): Radioactive Waste Management - Status and Trends -
Number 1.- IAEA WMDB-ST-1, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2002a): Procedures for Conducting Probabilistic Safety Assess-
ment for Non-Reactor Nuclear Facilities.- IAEA-TECDOC-1267, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2002b): Long Term Storage of Spent Nuclear Fuel - Survey and
Recommendations.- IAEA-TECDOC-1293, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2002c): Institutional Framework for Long Term Management of
High Level Waste and/or Spent Nuclear Fuel.- IAEA-TECDOC-1323, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2002d): Radioactive Waste Management Proles - Number 4. A
Compilation of Data from the Net Enabled Waste Management Database.- IAEA-RWMP-V4, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2002e): Radioactive Waste Management - Status and Trends -
Number 2.- IAEA WMDB-ST-2, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003a): Scientic and Technical Basis for the Geological Disposal
of Radioactive Wastes.- Technical Reports Series No. 413, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003b): Effects of Radiation and Environmental Factors on the
Durability of Materials in Spent Fuel Storage and Disposal.- IAEA-TECDOC-1316, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003c): Safety Indicators for the Safety Assessment of Radioac-
tive Waste Disposal.- IAEA-TECDOC-1372, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003d): Radioactive Waste Management - Status and Trends -
Number 3.- IAEA WMDB-ST-3, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003e): “Reference Biospheres” for Solid Radioactive Waste Dis-
posal (IAEA BIOMASS-6).- IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003f): The Long Term Storage of Radioactive Waste: Safety and
Sustainability A Position Paper of International Experts.- IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003h): Radioactive Waste Management Proles - Number 5. A
Compilation of Data from the Net Enabled Waste Management Database.- IAEA-RWMP-V5, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003i): International Conference on Issues and Trends in Radioac-
tive Waste Management, Vienna, 7-11 December 2002, Proceedings Series, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2003j): Radioactive Waste Management Glossary. 2003 Edition.-
IAEA Publication STI/PUB/1155, Vienna.
JRC Reference Report
44
INTERNATIONAL ATOMIC ENERGY AGENCY (2004a): Implications of Partitioning and Transmutation in Radio-
active Waste Management.- Technical Reports Series No. 435, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2004b): Records for Radioactive Waste Management up to Reposi-
tory Closure: Managing the Primary Level Information (PLI) Set.- IAEA-TECDOC-1398, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2004c): Developing Multinational Radioactive Waste Repositor-
ies: Infrastructural Framework and Scenarios of Cooperation.- IAEA-TECDOC-1413, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2005a): Natural Activity Concentrations and Fluxes as Indicators
for the Safety Assessment of Radioactive Waste Disposal.- IAEA-TECDOC-1464, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2005b): Technical, Economic and Institutional Aspects of Regional
Spent Fuel Storage Facilities.- IAEA-TECDOC-1482, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2005c): Anthropogenic Analogues for Geological Disposal of High
Level and Long Lived Waste.- IAEA-TECDOC-1481, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2005d): Radioactive Waste Management Proles - Number 6. A
Compilation of Data from the Net Enabled Waste Management Database.- IAEA-RWMP-V6, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2005e): Radioactive Waste Management Proles - Number 7. A
Compilation of Data from the Net Enabled Waste Management Database.- IAEA-RWMP-V7, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2005f): Radioactive Waste Management - Status and Trends
Number 4.- IAEA WMDB-ST-4, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2006a): Geological Disposal of Radioactive Waste Safety Require-
ments.- Safety Standards Series No. WS-R-4, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2006b): Safety of Radioactive Waste Disposal Proceedings of an
International Conference held in Tokyo, Japan, 3-7 October 2005.- Proceedings Series, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2007a): Nuclear Fuel Cycle Simulation System (VISTA).- IAEA-TEC-
DOC-1535, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2007b): Retrieval, Restoration and Maintenance of Old Radioac-
tive Waste Inventory Records.- IAEA-TECDOC-1548, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2007c): Factors Affecting Public and Political Acceptance for the
Implementation of Geological Disposal.- IAEA-TECDOC-1566, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (2007d): IAEA Safety Glossary Terminology Used in Nuclear Safety
and Radiation Protection. 2007 Edition.- IAEA Publication STI/PUB/1290, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (in press): Natural Safety Indicators for Use in Relation to Radioac-
tive Waste Disposal: Synthesis of CRP Results.- IAEA-TECDOC, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (in prep. a): A Common Framework for the Disposal of Radioactive
Waste.- TECDOC in preparation, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (in prep. b): Model Regulations on Safety of Radioactive Waste
Management.- Safety Report in preparation, IAEA, Vienna.
JRC Reference Report
45
INTERNATIONAL ATOMIC ENERGY AGENCY (in prep. c): Preservation and Transfer to Future Generations of In-
formation Important for the Safety of Radioactive Waste Disposal Facilities.- Safety Report in prepa-
ration, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (in prep. d): Standard Syllabus of Training on Radioactive Waste
Management.- TECDOC in preparation, Vienna
INTERNATIONAL ATOMIC ENERGY AGENCY (in prep. e): Sustainability and Safety Implications of Long Term
Storage and Radioactive Waste.- TECDOC in preparation, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (in prep. f ): Disposal of Radioactive Waste.- Draft Safety Require-
ments, DS354, IAEA, Vienna.
INTERNATIONAL ATOMIC ENERGY AGENCY (in prep. g): Technological Implications of Retrievability on Geo-
logical Disposal of Radioactive Waste.- IAEA-TECDOC, Vienna.
KOTRA, J., ATHERTON, E., PESC ATORE , C. (2007): Regional development and community support in radioac-
tive waste management. A national workshop and community visit in Hungary.- NEA News, (1):
13-15.
LACOSTE, A.-C. (2007): The international approach to harmonise the requirements and the process for a
geological repository.- Geological Repositories: A Common Objective, A Variety of Paths, Internat.
Conf., Berne, 15-17 October 2007,
http://www.icgr2007.org/Proceedings/Session%205/Presentations/Session5_4_Lacoste.pdf
LESKINEN, A. et al. (2007): Determination of Granites Mineral Specic Porosities by PMMA and FESEM/
EDAX.- 2nd Annual Workshop Proceedings of the Integrated Project “Fundamental Processes of Ra-
dionuclide Migration” – 6th EC FP IP FUNMIG, SKB Technical Report TR-07-05: 321-327.
MAZUREK, M., PEARSON, F.J., VOLCKAERT, G. (2003): Features, Events and Processes Evaluation Catalogue
for Argillaceous Media.- NEA 4437, 379 p., OECD-NEA, Paris.
MAYS, C., PESCATORE, C. (2007): Fostering a durable relationship between a waste management facility
and its host community. Adding value through design and process.- NEA News, (1): 10-12.
MILLER, W., ALEXANDER, R., CHAPMAN, N., MCKINLEY, I., SMELLIE, J. (2000): Geological disposal of radioac-
tive wastes and natural analogues.- Pergamon Press, Elsevier Science, New York, 316 pp.
MOLL, H., MERROUN, M., GEIPEL, G., STUMPF, T., ROSSBERG, A., HENNING, C., SELENSKA-POBELL, S., BERN-
HARD, G. (2007): Interactions of Microbes Found at Äspö Underground Lab with Actinides such as
Curium, Plutonium and Uranium.- 2nd Annual Workshop Proceedings of the Integrated Project “Fun-
damental Processes of Radionuclide Migration” – 6th EC FP IP FUNMIG, SKB Technical Report TR-07-
05: 131-137.
OECD-NUCLEAR ENERGY AGENCY (1997a): Lessons Learnt from Ten Performance Assessment Studies.- 132
p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (1997b): Field Tracer Experiments. Role in the Prediction of Radionuclide
Migration.- ISBN: 9789264160132, 256 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (1997c): Regulating the Long-Term Safety of Radioactive Waste Disposal.-
Proc. of a Workshop held 20-23 January 1997, OECD-NEA, Paris.
JRC Reference Report
46
OECD-NUCLEAR ENERGY AGENCY (1998): Modelling the Effects of Spatial Variability on Radionuclide Migra-
tion. Paris, France - 9-11 June 1997.- ISBN: 9789264160996, 356 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (1999a): Condence in the Long-term Safety of Deep Geological Repositor-
ies. Its Development and Communication.- 83 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (1999b): Water-conducting Features in Radionuclide Migration. Workshop
Proceedings, Barcelona, Spain, 10-12 June 1998.- ISBN: 9789264171244, 380 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2000a): Features, Events and Processes (FEPs) for Geologic Disposal of
Radioactive Waste. An International Database.- ISBN: 9789264185142, 92 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2000b): Stakeholder Condence and Radioactive Waste Disposal. Inau-
guration, First Workshop and Meeting of the NEA Forum on Stakeholder Condence in the Area of
Radioactive Waste Management, Paris, France, 28-31 August 2000.- 164 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2000c): Regulatory Reviews of Assessments of Deep Geologic Repositor-
ies. Lessons Learnt.- ISBN: 9789264058866, 136 p. , OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2001a): IGSC Working Group on Measurement and Physical Understand-
ing of Groundwater Flow through Argillaceous Media (CLAY CLUB): Self-Healing Topical Session Pro-
ceedings, Nancy-France, 16 May 2001.- NEA/RWM/CLAYCLUB(2001)5, 63., OECD-NEA, Paris.
OECD-NUCLEAR E NERGY AGENCY (2001b): Gas Generation and Migration in Radioactive Waste Disposal Safe-
ty-relevant Issues. Workshop Proceedings, Reims, France, 26-28 June 2000.- ISBN: 9789264186729,
192 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2001c): Condence in Models of Radionuclide Transport for Site-specic
Assessment. Workshop Proceedings, Carlsbad, New Mexico, United States, 14-17 June 1999.- ISBN:
9789264186200, 336 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2001d): Scenario Development Methods and Practice. An Evaluation
Based on the NEA Workshop on Scenario Development - Madrid, May 1999.- ISBN: 9789264187221,
248 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2001e): Reversibility and Retrievability in Geologic Disposal of Radioac-
tive Waste. Reections at the International Level.- 52 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2002a): GEOTRAP: Radionuclide Migration in Geologic, Heterogeneous
Media. Summary of Accomplishments.- NEA Report 3058, 52 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2002b): Radionuclide Retention in Geologic Media. Workshop Proceed-
ings - Oskarshamn, Sweden - 7-9 May 2001.- ISBN: 9789264196957, 276 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2002c): Forum on Stakeholder Condence (FSC). 2nd FSC Workshop - Ex-
ecutive Summary and International Perspective. Stakeholder Involvement and Condence in the Proc-
ess of Decision-making for the Disposal of Spent Nuclear Fuel in Finland.- NEA/RWM/FSC(2002)1, 18
p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2002d): Forum on Stakeholder Condence (FSC). Stepwise Decision Mak-
ing in Finland for the Disposal of Spent Nuclear Fuel. Workshop Proceedings - Turku, Finland - 15-16
November 2001.- ISBN: 9789264199415, 157 p., OECD-NEA, Paris.
JRC Reference Report
47
OECD-NUCLEAR ENERGY AGENCY (2002e): Establishing and Communicating Condence in the Safety of Deep
Geologic Disposal Approaches and Arguments.- ISBN: 9789264097827, 186 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2002f): Strategic Directions of the RWMC Forum on Stakeholder Con-
dence.- NEA/RWM/FSC(2001)2/REV2, 7 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003a): Fuels and Materials for Transmutation. A Status Report.- 240 p.,
OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003b): Stability and Buffering Capacity of the Geosphere for Long-term
Isolation of Radioactive Waste. Application to Argillaceous Media - “Clay Club” Workshop Proceed-
ings, Braunschweig, Germany, 9-11 December 2003.- 244 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003c): Engineered Barrier Systems and the Safety of Deep Geological
Repositories. State-of-the-art Report.- ISBN 92-64-18498-8 and also EUR 19964 EN, 71 p., OECD-NEA,
Paris.
OECD-NUCLEAR ENERGY AGENCY (2003d): Engineered Barrier Systems (EBS) in the Context of the En-
tire Safety Case. Workshop Proceedings, Oxford, United Kingdom 25-27 September 2002.- ISBN:
9789264103542, 156 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003e): Public Information, Consultation and Involvement in Radioactive
Waste Management. An International Overview of Approaches and Experiences.- ISBN 92-64-02128-
0, OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003f ): The Regulator’s Evolving Role and Image in Radioactive Waste
Management. Lessons Learnt within the NEA Forum on Stakeholder Condence.- ISBN 92-64-02142-
6, 27 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003g): Stakeholder Participation in Radiological Decision Making: Proc-
esses and Implications (Villigen 3). Third Villigen Workshop, Villigen, Switzerland, 21-23 October
2003.- 64 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003h): Stakeholder Participation in Radiological Decision Making: Proc-
esses and Implications. Case Studies for the Third Villigen Workshop, Villigen, Switzerland, 21-23
October 2003.- 104 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003i): Forum on Stakeholder Condence (FSC). Canadian Site Visit and
Workshop - Summary and International Perspective.- NEA/RWM/FSC(2003)8, 27 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003j): Public Condence in the Management of Radioactive Waste:
The Canadian Context. Workshop Proceedings, Ottawa, Canada, 14-18 October 2002.- ISBN:
9789264103962, 196 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2003k): Forum on Stakeholder Condence (FSC). Stakeholder Involve-
ment Tools: Criteria for Choice and Evaluation. Proceedings of a Topical Session at the 4th meeting
of the NEA Forum on Stakeholder Condence, May 22, 2003.- NEA/RWM/FSC(2003)10, 49 p., OECD-
NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004a): Stakeholder Participation in Radiological Decision Making: Proc-
esses and Implications. Summary Report of the 3rd Villigen (Switzerland) Workshop, October 2003.-
36 p., OECD-NEA, Paris.
JRC Reference Report
48
OECD-NUCLEAR ENERGY AGENCY (2004b): Dealing with Interests, Values and Knowledge in Managing Risk.
Workshop Proceedings, Brussels, Belgium, 18-21 November 2003.- 172 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004c): Engineered Barrier Systems (EBS): Design Requirements and
Constraints. Workshop Proceedings, Turku, Finland, 26-29 August 2003.- NEA Report No. 4548, 148
p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004d): Geological Disposal: Building Condence Using Multiple Lines of
Evidence. First AMIGO Workshop Proceedings, Yverdon-les-Bains, Switzerland, 3-5 June 2003.- 204
p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004e): Learning and Adapting to Societal Requirements for Radioactive
Waste Management. Key Findings and Experience of the Forum on Stakeholder Condence.- 70 p.,
OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004f ): Stakeholder Involvement Techniques. Short Guide and Annotated
Bibliography.- NEA/RWM/FSC(2004)7, 30 p.
OECD-NUCLEAR ENERGY AGENCY (2004g): Post-closure Safety Case for Geological Repositories. Nature and
Purpose.- NEA Report No. 3679, ISBN 92-64-02075-6, 56 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004h): Safety of Disposal of Spent Fuel, HLW and Long-lived ILW in Swit-
zerland. An International Peer Review of the Post-closure Radiological Safety Assessment for Dis-
posal in the Opalinus Clay of the Zürcher Weinland.- 126 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004i): Stepwise Approach to Decision Making for Long-term Radioactive
Waste Management. Experience, Issues and Guiding Principles.- 76 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004j): The Handling of Timescales in Assessing Post-closure Safety. Les-
sons Learnt from the April 2002 Workshop in Paris, France.- 52 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004k): The Regulatory Control of Radioactive Waste Management. Over-
view of 15 NEA Member Countries.- 210 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004l): Forum on Stakeholder Condence (FSC). Belgian Workshop (No-
vember 2003) - Executive Summary and International Perspective.- NEA/RWM/FSC(2004)4, 27 p.,
OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2004m): Forum on Stakeholder Condence (FSC). Topical Session on “Ad-
dressing Issues Raised by Stakeholders: Impacts on Process, Content and Behaviour in Waste Or-
ganisations”, Paris, 2nd June 2004.- NEA/RWM/FSC(2004)8, 72 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005a): Actinide and Fission Product Partitioning and Transmutation. 8th In-
formation Exchange Meeting, Las Vegas, Nevada, USA, 9-11 November 2004.- 160 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005b): Clay Club Catalogue of Characteristics of Argillaceous Rocks.- 72
p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005c): Engineered Barrier Systems (EBS) in the Context of the Entire
Safety Case. Process Issues - Workshop Proceedings, Las Vegas, United States, 14-17 September
2004.- 156 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005d): Geological Repositories: Political and Technical Progress. Work-
shop Proceedings, Stockholm, Sweden, 8-10 December 2003.- 250 p., OECD-NEA, Paris.
JRC Reference Report
49
OECD-NUCLEAR ENERGY AGENCY (2005e): International Peer Reviews for Radioactive Waste Management.
General Information and Guidelines, 36 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005f): Management of Uncertainty in Safety Cases and the Role of Risk.
Workshop Proceedings, Stockholm, Sweden, 2-4 February 2004.- 236 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005g): NEA Sorption Project Phase II. Interpretation and Prediction of
Radionuclide Sorption onto Substrates Relevant for Radioactive Waste Disposal Using Thermody-
namic Sorption Models.- 290 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005h): Radioactive Waste Management Programmes in OECD/NEA Mem-
ber Countries.- 124 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005i): The Regulatory Function and Radioactive Waste Management.
International Overview.- 24 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005j): The Strategic Plan of the Nuclear Energy Agency - 2005-2009.
Summary.- 12 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005k): The Strategic Plan of the Nuclear Energy Agency - 2005-2009.- 12
p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005l): Disposal of Radioactive Waste: The Forming of A New Approach
in Germany. Summary and international perspective. FSC Community Visit and National Workshop,
Hitzacker, Hamburg, 5-8 October 2004, 29 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005m): Dealing with Interests, Values and Knowledge in Managing Risk.
Workshop Proceedings, Brussels, Belgium 18-21 November 2003.- ISBN 9789264007314, 172 p.,
OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2005n): Integration Group for the Safety Case (IGSC). Topical Session Pro-
ceedings of the 6th IGSC Meeting. The Role of Monitoring in a Safety Case.- NEA/RWM/IGSC(2005)3,
110 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006a): Advanced Nuclear Fuel Cycles and Radioactive Waste Manage-
ment.- 248 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006b): Disposal of Radioactive Waste: Forming a New Approach in Ger-
many. FSC Workshop Proceedings, Hitzacker and Hamburg, Germany, 5-8 October 2004.- 116 p.,
OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006c): Safety of Geological Disposal of High-level and Long-lived Ra-
dioactive Waste in France. An International Peer Review of the “Dossier 2005 Argile” Concerning
Disposal in the Callovo-Oxfordian Formation.- 80 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006d): The Roles of Storage in the Management of Long-lived Radioac-
tive Waste. Practices and Potentialities in OECD Countries.- 64 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006e): Coordination of Decision Making in Spain. The “COWAM SPAIN”
Initiative and the Current Project Under Consideration for a National Interim Storage Facility for Spent
Fuel and High Level Waste. The Sixth Workshop of the Forum on Stakeholder Condence. Executive
Summary and International Perspective.- NEA/RWM/FSC(2006)7, 25 p., OECD-NEA, Paris.
JRC Reference Report
50
OECD-NUCLEAR ENERGY AGENCY (2006f): Organisational Change: Cultural and Structural Aspects. Proceed-
ings of a Topical Session held during the 7th Session of the NEA Forum on Stakeholder Condence,
7-9 June 2006, Paris.- NEA/RWM/FSC(2007)3, 64 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006g): Forum on Stakeholder Condence (FSC). Proceedings of the Topi-
cal Sessions on Media Relations held in June 2004 and 2005.- NEA/RWM/FSC(2006)5, 73 p., OECD-
NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006h): Proceedings of the Topical Session of the 6th Meeting of the FSC
on “The Link Between R&D and Stakeholder Condence” held on the 9 June 2005 at the OECD HQ in
Paris, France.- NEA/RWM/FSC(2006)4, 77 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006i): Consideration of Timescales in Post-Closure Safety of Geological
Disposal of Radioactive Waste.- NEA/RWM/IGSC(2006)3, 157 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2006j): Advanced Nuclear Fuel Cycles and Radioactive Waste Manage-
ment. - 244 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2007a): Engineered Barrier Systems (EBS) in the Safety Case: The Role of
Modelling. Workshop Proceedings, La Coruña, Spain, 24-26 August 2005.- 192 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2007b): Fostering a Durable Relationship Between a Waste Man-
agement Facility and its Host Community. Adding Value Through Design and Process.- 60 p.,
OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2007c): Linkage of Geoscientic Arguments and Evidence in Supporting
the Safety Case. Second AMIGO Workshop Proceedings, Toronto, Canada, 20-22 September 2005.-
275 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2007d): The Long-Term Regulatory Criteria for Radioactive Waste Dis-
posal. Towards a Common Understanding of the Objectives, Challenges and Practical Issues.- 63 p.,
NEA/RWMC/RF(200)1/ROV, OECD-NEA, Paris.
OECD-NUCLEAR ENERGY A GENCY (2007e): 3rd AMIGO Workshop on Approaches and Challenges for the Use Of
Geological Information in the Safety Case. Preliminary Programme.- 16 p., NEA/RWM/IGSC(2007)4/
PROV, OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2007f): Radiation Protection in Today’s World: Towards Sustainability.-
NEA Report 6165: 72 p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2007g): Regulating the Long-term Safety of Geological Disposal. Towards
a Common Understanding of the Main Objectives and Bases of Safety Criteria.- NEA Report 6182: 82
p., OECD-NEA, Paris.
OECD-NUCLEAR ENERGY AGENCY (2008a): Progress in International Regulations for Geological Disposal
since Cordoba.- NEA/RWM/RF(2008)2/PROV, 20 p.
OECD-NUCLEAR ENERGY AGENCY (2008b): Preliminary Literature Review on: Optimisation and Best Avail-
able Techniques for Geological Disposal.- NEA/RWM/RF(2008)3/PROV, 29 p.
OECD-NUCLEAR ENERGY AGENCY (2008c): Safety Cases for Deep Geological Disposal of Radioactive Waste:
Where Do We Stand?.- Proc. Symp., Paris, France, 23-25 January 2007, NEA Report 6319: 423 p.,
OECD-NEA, Paris.
JRC Reference Report
51
OECD-NUCLEAR ENERGY AGENCY (2008d): Moving Forward With Geological Disposal of High-Activity Radio-
active Waste – A collective statement of the NEA RWMC.- 2 p., OECD-NEA, Paris.
OELKERS, E.H., MONTEL, J.-M. (2008): Phosphates and Nuclear Waste Storage.- Elements (2):113-116.
PEDERSEN, K (1999): Subterranean Microorganisms and Radioactive Waste Disposal in Sweden.- Engineer-
ing Geol., 52: 163-176.
PITZER, K. S. [Ed.] (1991): Activity Coefcients in Electrolyte Solutions.- 2nd ed., 542 p., Boca Raton (CRC
Press).
PLUMTRE, T. (2006): What is Governance?.- Institute on Governance (http://www.iog.ca/).
VANCE, E.R. (2007): Development of Ceramic Waste Forms for High-Level Nuclear Waste Over the Last 30
Years.- Mater. Res. Soc. Symp. Proc., : paper 0985-NN04-01, 8 p.
VARI, A. (2004): The Mental Models Approach to Risk Research - An RWM Perspective.- Unclassied NEA/
RWM/FSC(2003)7/REV1, 28 p., OECD-NEA, Paris.
VARI, A., PE SCATORE, C. (2006): Forum on Stakeholder Condence: Spain. – NEA News,(1): 11-13.
Various authors (1992-2007): Chemical Thermodynamics 1-10. Results of the TDB Project.
WESTERN EUROPEAN NUCLEAR REGUL ATOR’S ASSOCIATION (2006): Waste and Spent Fuel Storage Safety
Reference Levels Report.- Draft Version 1.0, December 2006, 37 p., WENRA. http://www.wenra.org/
dynamaster/le_archive/070718/327631f8acb266a075aa84a9a7846167/V1%5f0%5fstorage%5fre
port%5fnal.pdf.
JRC Reference Report
European Commission
EUR 23925 EN – Joint Research Centre – Institute for Energy
Title: Geological Disposal of Radioactive Waste: Moving Towards Implementation
Authors: W.E. Falck and K.-F. Nilsson
Luxembourg: Ofce for Ofcial Publications of the European Communities
2009 – 52 pp. – 21.0 x 29.7 cm
EUR – Scientic and Technical Research series – ISSN 1018-5593
ISBN 978-92-79-12697-0
Catalogue number LD-NA-23925-EN-C
DOI 10.2790/12387
Abstract
The present report reviews the current state of science and technology that form the basis for implementing geological repositories for
high-level nuclear waste and spent nuclear fuel. It is concluded that enough is known about the relevant natural and man-made systems to
proceed with a step-wise implementation. The scope for harmonisation of procedures and regulations on a European level is investigated.
Public acceptance of the scientically preferred solution of deep disposal is still low in many European countries and more needs to be done
to involve stakeholders in decision making processes in a meaningful way. It also needs to be ensured that national regulators are enabled
to adequately process license applications for deep repositories.
The mission of the Joint Research Centre (JRC) is to provide customer-driven scientic and technical sup-
port for the conception, development, implementation and monitoring of European Union policies. As a
service of the European Commission, the JRC functions as a reference centre of science and technology for
the Union. Close to the policy-making process, it serves the common interest of the Member States, while
being independent of special interests, whether private or national.
LD-NA-23925-EN-C
