Radioactive Waste Management Publications
Alphabetical list of titles
Detailed publication list
Stakeholder Confidence in Radioactive Waste Management
An Annotated Glossary of Key Terms
English, 64 pages, published: 03/01/13
Available online at: http://www.oecd-nea.org/rwm/docs/2013/6988-fsc-glossary.pdf
The OECD Nuclear Energy Agency (NEA) Forum on Stakeholder Confidence (FSC) Annotated Glossary is a review of concepts central to societal decision making about radioactive waste management. It records the evolution in understanding that has taken place in the group as the FSC has worked with these concepts over time. This should be a useful resource not only for new FSC participants but also for others: this annotated glossary forms a good reference handbook for future texts regarding societal aspects of radioactive waste management and its governance.
Geological Disposal of Radioactive Waste: National Commitment, Local and Regional Involvement
A Collective Statement of the OECD Nuclear Energy Agency Radioactive Waste Management Committee Adopted March 2012
English, 24 pages, published: 07/18/12
NEA#7082, ISBN: 978-92-64-99183-5
Available online at: http://www.oecd-nea.org/rwm/reports/2012/7082-geo-disposal-statement.pdf
- Français: Stockage géologique des déchets radioactifs :
Engagement national, participation locale et régionale
Disposal in engineered facilities built in stable, deep geological formations is the reference solution for permanently isolating long-lived radioactive waste from the human biosphere. This management method is designed to be intrinsically safe and final, meaning that it is not dependent on human presence or intervention in order to fulfil its safety goal. Selecting the site of a waste repository brings up a range of issues involving scientific knowledge, technical capacity, ethical values, territorial planning, community well-being and more. Bringing to fruition the multi-decade task of siting and developing a repository demands a strong national commitment and significant regional and local involvement.
This collective statement by the Radioactive Waste Management Committee of the OECD Nuclear Energy Agency recognises the advances made towards greater transparency and dialogue among the diverse stakeholders concerned and identifies the fundamental elements needed to support national commitment and to foster territorial involvement. It concludes that technical and societal partners can develop shared confidence in the safety of geological repositories and jointly carry these projects forward.
International Structure for Decommissioning Costing (ISDC) of Nuclear Installations
English, 192 pages, published: 03/02/12
NEA#7088, ISBN: 978-92-64-99173-6
Available online at: http://www.oecd-nea.org/rwm/reports/2012/ISDC-nuclear-installations.pdf
Cost estimation for the decommissioning of nuclear facilities can vary considerably in format, content and practice both within and across countries. These differences may have legitimate reasons but make the process of reviewing estimates complicated and the estimates themselves difficult to defend. Hence, the joint initiative of the OECD Nuclear Energy Agency (NEA), the International Atomic Energy Agency (IAEA) and the European Commission (EC) was undertaken to propose a standard itemisation of decommissioning costs either directly for the production of cost estimates or for mapping estimates onto a standard, common structure for purposes of comparison. This report updates the earlier itemisation published in 1999 and takes into account experience accumulated thus far. The revised cost itemisation structure has sought to ensure that all costs within the planned scope of a decommissioning project may be reflected. The report also provides general guidance on developing a decommissioning cost estimate, including detailed advice on using the structure.
Methods for Safety Assessment of Geological Disposal Facilities for Radioactive Waste
Outcomes of the NEA MeSA Initiative
English, 240 pages, published: 06/21/12
NEA#6923, ISBN: 978-92-64-99190-3
Available online at: http://www.oecd-nea.org/rwm/reports/2012/nea6923-MESA-initiative.pdf
Safety assessment is an interdisciplinary approach that focuses on the scientific understanding and performance assessment of safety functions as well as the hazards associated with a geological disposal facility. It forms a central part of the safety case, and the results of the safety assessments provide evidence to support decision making. The goals of the NEA project on “Methods for Safety Assessment for Geological Disposal Facilities for Radioactive Waste” (MeSA) were to examine and document methods used in safety assessment for radioactive waste disposal facilities, to generate collective views based on the methods’ similarities and differences, and to identify future work. The project reviewed a number of approaches used by various national and international organisations. Following the comprehensive review, a generic safety case with a safety assessment flowchart was developed and is presented herein. The elaboration of the safety concept, the use of safety functions, the implication of uncertainties and the formulation of scenarios are also discussed.
Reversibility and Retrievability in Planning for Geological Disposal of Radioactive Waste
Proceedings of the "R&R" International Conference and Dialogue, 14-17 December 2010, Reims, France
English, 236 pages, published: 12/31/12
NEA#6993, ISBN: 978-92-64-99185-9
Available online at: http://www.oecd-nea.org/rwm/docs/2012/6993-proceedings-rr-reims.pdf
Deep geological repositories of radioactive waste are designed and licensed based on a model of long-term safety which does not require the active presence of man. During the period of stepwise development of such repositories, reversibility of decisions and retrievability of the waste are widely thought to be beneficial. Reversibility and retrievability are not requirements for long-term safety. They are instead about implementing a process that responds to ethical and precautionary obligations without compromising safety. How are the concepts of reversibility and retrievability understood in the various nuclear countries? How do they appear in national waste management legislation, regulation and operational programmes, and how can they be implemented?
The “R&R” project of the OECD Nuclear Energy Agency (NEA) culminated in an International Conference and Dialogue on Reversibility and Retrievability in December 2010. This open meeting brought together regulators, policy makers, elected officials, experts in social sciences, and representatives of civil society and stakeholder groups in addition to waste management professionals. These proceedings include the texts of 50 presentations and the “International Retrievability Scale” – a tool to support dialogue with stakeholders and to help establish a common international framework.
Reversibility of Decisions and Retrievability of Radioactive Waste
Considerations for National Geological Disposal Programmes
English, 28 pages, published: 03/09/12
NEA#7085, ISBN: 978-92-64-99169-9
Available online at: http://www.oecd-nea.org/rwm/reports/2012/7085-reversibility.pdf
- Français: Réversibilité des décisions et récupérabilité des déchets radioactifs
The most widely adopted solution for the definitive management of high-level radioactive waste involves its emplacement in deep geological repositories whose safety should not depend on the active presence of man. In this context, national programmes are considering whether and how to incorporate the concepts of reversibility of decisions and retrievability of waste, including to what extent retrieval can or should be facilitated at the design stage of a repository, and if so over what timescales.
This brochure delivers the key findings and observations of the OECD Nuclear Energy Agency (NEA) project on reversibility and retrievability conducted from 2007 to 2011 with the participation of 15 countries and 2 international organisations. It outlines the activities undertaken and points to further resources. While focused on deep geological disposal, the pragmatic and precise information provided may also be pertinent to sub-surface disposal and to decision-making processes more generally. This brochure, and related project documents, will be of interest to technical and policy professionals and civil society stakeholders concerned with radioactive waste disposal.
The Evolving Role and Image of the Regulator in Radioactive Waste Management
Trends over Two Decades
English, 28 pages, published: 12/31/12
NEA#7083, ISBN: 978-92-64-99186-6
Available online at: http://www.oecd-nea.org/rwm/docs/2012/7083-evolving-role-and-image.pdf
- Français: Image et rôle de l'autorité de sûreté nucléaire dans la gestion des déchets radioactifs
In the area of radioactive waste management, the regulator or safety authority has emerged in recent years as a principal actor in the eyes of civil society. This study shows how regulators are increasing their interaction with society while still retaining – or reinforcing – their independence and how they play their role within the stepwise licensing and decision-making processes now adopted in most countries. Safety is ensured by a “regulatory system”, in which a host of players, including local stakeholders, have a vital role to play. The technical regulator has come to be considered as the “people’s expert”, concentrating knowledge useful to local communities as they deliberate the hosting of a waste storage or disposal facility.
This report provides a useful update on the changing role of the regulator as well as insights that will be helpful to the many countries that are considering, or are preparing for, storage or disposal of radioactive waste either in near-surface facilities or deeper underground. While it focuses on the developments in waste management and disposal, the trends it describes are probably relevant throughout the nuclear field.
The Long-term Radiological Safety of a Surface Disposal Facility for Low-level Waste in Belgium
An International Peer Review of Key Aspects of ONDRAF/NIRAS' Safety Report of November 2011 in Preparation for the License Application
English, 100 pages, published: 10/08/12
NEA#7086, ISBN: 978-92-64-99196-5
Available online at: http://www.oecd-nea.org/rwm/reports/2012/7086-Belgian-peer-review.pdf
An important activity of the OECD Nuclear Energy Agency (NEA) in the field of radioactive waste management is the organisation of independent, international peer reviews of national studies and projects. This report provides an international peer review of the long-term safety strategy and assessment being developed by the Belgian Agency for Radioactive Waste and Enriched Fissile Materials, ONDRAF/NIRAS, as part of the licence application for the construction and operation of a surface disposal facility for short-lived, low- and intermediate-level radioactive waste in the municipality of Dessel, Belgium. The review was carried out by an International Review Team comprised of seven international specialists, all of whom were free of conflict of interest and chosen to bring complementary expertise to the review. To be accessible to both specialist and non-specialist readers, the review findings are provided at several levels of detail.
The Post-closure Radiological Safety Case for a Spent Fuel Repository in Sweden
An International Peer Review of the SKB License-application Study of March 2011
English, 156 pages, published: 07/05/12
NEA#7084, ISBN: 978-92-64-99191-0
Available online at: http://www.oecd-nea.org/rwm/docs/2012/nea7084-peer-review-sweden.pdf
Sweden is at the forefront among countries developing plans for a deep geological repository of highly radioactive waste. There is no such repository in operation yet worldwide, but Sweden, Finland and France are approaching the licensing stage. At the request of the Swedish government, the NEA organised an international peer review of the post-closure radiological safety case produced by the Swedish Nuclear Fuel and Waste Management Company (SKB) in support of the application for a general licence to construct and operate a spent nuclear fuel geological repository in the municipality of Östhammar. The purpose of the review was to help the Swedish government, the public and relevant organisations by providing an international reference regarding the maturity of SKB’s spent fuel disposal programme vis-à-vis best practices in long-term disposal safety and radiological protection. The International Review Team (IRT) consisted of ten international specialists, who were free of conflict of interest with the SKB and brought complementary expertise to the review. This report provides the background and findings of the international peer review. The review’s findings are presented at several levels of detail in order to be accessible to both specialist and non-specialist readers.
Thermodynamic Sorption Modelling in Support of Radioactive Waste Disposal Safety Cases
NEA Sorption Project Phase III
English, 152 pages, published: 05/04/12
NEA#6914, ISBN: 978-92-64-17781-9
Available online at: http://www.oecd-nea.org/rwm/docs/2013/6914-sorption-III.pdf
A central safety function of radioactive waste disposal repositories is the prevention or sufficient retardation of radionuclide migration to the biosphere. Performance assessment exercises in various countries, and for a range of disposal scenarios, have demonstrated that one of the most important processes providing this safety function is the sorption of radionuclides along potential migration paths beyond the engineered barriers. Thermodynamic sorption models (TSMs) are key for improving confidence in assumptions made about such radionuclide sorption when preparing a repository's safety case. This report presents guidelines for TSM development as well as their application in repository performance assessments. They will be of particular interest to the sorption modelling community and radionuclide migration modellers in developing safety cases for radioactive waste disposal.
Applying Decommissioning Experience to the Design and Operation of New Nuclear Power Plants
English, 56 pages, published: 04/21/10
NEA#6924, ISBN: 978-92-64-99118-7
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6924-applying-decommissioning.pdf
- Français: Intégration du retour d'expérience du démantèlement à la conception et l'exploitation des futures centrales nucléaires
Experience from decommissioning projects suggests that the decommissioning of nuclear power plants could be made easier if it received greater consideration at the design stage and during the operation of the plants. Better forward planning for decommissioning results in lower worker doses and reduced costs. When appropriate design measures are not taken at an early stage, their introduction later in the project becomes increasingly difficult. Hence, their early consideration may lead to smoother and more effective decommissioning.
It is now common practice to provide a preliminary decommissioning plan as part of the application for a licence to operate a nuclear facility. This means, in turn, that decommissioning issues are being considered during the design process. Although many design provisions aiming at improved operation and maintenance will be beneficial for decommissioning as well, designers also need to consider issues that are specific to decommissioning, such as developing sequential dismantling sequences and providing adequate egress routes. These issues and more are discussed in this report.
Cost Estimation for Decommissioning
An International Overview of Cost Elements, Estimation Practices and Reporting Requirements
English, 80 pages, published: 05/17/10
NEA#6831, ISBN: 978-92-64-99133-0
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6831-cost-estimation-decommissioning.pdf
This report is based on a study carried out by the NEA Decommissioning Cost Estimation Group (DCEG) on decommissioning cost elements, estimation practices and reporting requirements. Its findings indicate that cost methodologies need to be updated continuously using cost data from actual decommissioning projects and hence, systematic approaches need to be implemented to collect these data. The study also concludes that changes in project scope may have the greatest impact on project costs. Such changes must therefore be identified immediately and incorporated into the estimate. Finally, the report notes that more needs to be done to facilitate the comparison of estimates, for example by providing a reporting template for national estimates.
Decommissioning Considerations for New Nuclear Power Plants
English, 16 pages, published: 06/07/10
NEA#6833, ISBN: 978-92-64-99132-3
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6833-decommissioning-considerations.pdf
Experience from decommissioning projects suggests that the decommissioning of nuclear power plants could be made easier if this aspect received greater consideration at the design stage and during operation of the plants. Better forward planning for decommissioning results in lower worker doses and reduced costs. When appropriate design measures are not taken at an early stage, their introduction later in the project becomes increasingly difficult. Hence, their early consideration may lead to smoother and more effective decommissioning operations. This report provides an overview of key decommissioning issues which are useful to consider when designing new nuclear power plants.
Geoscientific Information in the Radioactive Waste Management Safety Case
Main Messages from the AMIGO Project
English, 56 pages, published: 09/24/10
NEA#6395, ISBN: 978-92-64-99138-5
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6395-AMIGO.pdf
- Français: Rôle des informations géoscientifiques dans le dossier de sûreté pour la gestion des déchets radioactifs
Radioactive waste is associated with all phases of the nuclear fuel cycle as well as the use of radioactive materials in medicine, research and industry. For the most hazardous and long-lived waste, the solution being investigated worldwide is disposal in engineered repositories deep underground. The importance of geoscientific information in selecting a site for geological disposal has long been recognised, but there has been growing acknowledgement of the broader role of this information in assessing and documenting the safety of disposal. The OECD/NEA Approaches and Methods for Integrating Geological Information in the Safety Case (AMIGO) project has demonstrated that geological data and understanding serve numerous roles in safety cases. The project, which ran from 2002 to 2008, underscored the importance of integrating geoscientific information in the development of a disposal safety case and increasingly in the overall process of repository development, including, for example, siting decisions and ensuring the practical feasibility of repository layout and engineering.
More than Just Concrete Realities: The Symbolic Dimension of Radioactive Waste Management
English, 36 pages, published: 04/15/10
NEA#6869, ISBN: 978-92-64-99105-7
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6869-symbolic.pdf
- Français: Au-delà des seules réalités concrètes : la dimension symbolique de la gestion des déchets radioactifs
Key concepts of radioactive waste management, such as safety, risk, reversibility and retrievability, carry different meanings for the technical community and for non-technical stakeholders. Similarly, socio-economic concepts, including community, landscape and benefit packages, are interpreted differently by diverse societal groups. Opinions and attitudes are not simply a faithful reflection of decision making, actual events and communicated messages; perceptions and interpretations of events and objects also play a role. This report presents key issues and examples in order to build awareness of the importance of symbols and symbolism in communicating about perceptions and interpretations. It adds to the recognition that dialogue amongst stakeholders is shaped by dimensions of meaning that reach beyond dictionary definitions and are grounded in tradition and social conventions. A better understanding of these less obvious or conspicuous realities should help find additional ways of creating constructive relationships amongst stakeholders.
Optimisation of Geological Disposal of Radioactive Waste
National and International Guidance and Questions for Further Discussion
English, 28 pages, published: 03/11/10
NEA#6836, ISBN: 978-92-64-99107-1
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6836-optimisation-ENG.pdf
- Français: Optimisation des stockages géologiques de déchets radioactifs
As national geological disposal programmes progress towards implementation, the concept of “optimisation” and related requirements are receiving increased attention. Exchanges within NEA expert groups have shown that both regulators and implementers would benefit from a review of the relevant concepts and available guidance and experience. This report summarises and reviews the concepts relevant to the “optimisation” of geological disposal systems as they are outlined in national and international guidance. It also presents a set of observations and key questions. Overall, the report shows that, when addressing “optimisation”, there is ample scope for clarifying concepts, facts and possibilities and for ensuring that regulatory guidance is sufficiently precise and implementable. The intention is that this report should serve as a basis for discussion within and beyond NEA committees and expert groups.
Partnering for Long-term Management of Radioactive Waste
Evolution and Current Practice in Thirteen Countries
English, 132 pages, published: 04/06/10
NEA#6823, ISBN: 978-92-64-08369-1
Available online at: http://www.oecd-nea.org/rwm/pubs/2010/6823-partnering-management.pdf
- Français: Partenariats pour la gestion à long terme des déchets radioactifs
National radioactive waste management programmes are in various phases of siting facilities and rely on distinct technical approaches for different categories of waste. In all cases, it is necessary for institutional actors and the potential or actual host community to build a meaningful, workable relationship. Partnership approaches are effective in achieving a balance between the requirements of fair representation and competent participation. With host community support, they also help ensure the desirable combination of a licensable site and management concept as well as a balance between compensation, local control and development opportunities. This report provides up-to-date information on experience with local partnership arrangements in 13 countries. The characteristics, advantages and aims of community partnerships are also described in addition to the concept's evolution over the past decade.
Radioactive Waste Repositories and Host Regions: Envisaging the Future Together
Synthesis of the FSC National Workshop and Community Visit, Bar-le-Duc, France, 7-9 April 2009
English, 56 pages, published: 04/12/10
NEA#6925, ISBN: 978-92-64-99128-6
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6925-repositories-host-regions.pdf
- Français: Stockage des déchets radioactifs et territoires d'accueil : envisager l'avenir ensemble
This 7th Forum on Stakeholder Confidence (FSC) workshop focused on the territorial implementation of France’s high-level and long-lived intermediate-level waste management programme. Sessions addressed the French historical and legislative context, public information, reversibility, environmental monitoring and the issue of memory. Amongst the participants were representatives of local and regional governments, civil society organisations, universities, waste management agencies, institutional authorities and delegates from 13 countries. This report provides a synthesis of the workshop deliberations.
Self-sealing of Fractures in Argillaceous Formations in the Context of Geological Disposal of Radioactive Waste
Review and Synthesis
English, 312 pages, published: 06/01/10
NEA#6184, ISBN: 978-92-64-99095-1
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6184-self-sealing.pdf
Disposal of high-level radioactive waste and spent nuclear fuel in engineered facilities, or repositories, located deep underground in suitable geological formations is being developed worldwide as the reference solution to protect humans and the environment both now and in the future. Assessing the long-term safety of geological disposal requires developing a comprehensive understanding of the geological environment. The transport pathways are key to this understanding. Of particular interest are fractures in the host rock, which may be either naturally occurring or induced, for example, during the construction of engineered portions of a repository. Such fractures could provide pathways for migration of contaminants.
In argillaceous (clay) formations, there is evidence that, over time, fractures can become less conductive and eventually hydraulically insignificant. This process is commonly termed “self-sealing”. The capacity for self-sealing relates directly to the function of clay host rocks as migration barriers and, consequently, to the safety of deep repositories in those geological settings.
This report – conducted under the auspices of the NEA Clay Club – reviews the evidence and mechanisms for self-sealing properties of clays and evaluates their relevance to geological disposal. Results from laboratory tests, field investigations and geological analogues are considered. The evidence shows that, for many types of argillaceous formations, the understanding of self-sealing has progressed to a level that could justify its inclusion in performance assessments for geological repositories.
Towards Greater Harmonisation of Decommissioning Cost Estimates
English, 16 pages, published: 03/22/10
NEA#6867, ISBN: 978-92-64-99093-7
Volume of the series:
Radioactive Waste Management
Available online at: http://www.oecd-nea.org/rwm/reports/2010/nea6867-harmonisation.pdf
- Français: Vers une harmonisation des estimations des coûts du déclassement
Currently, the format, content and practice of cost estimation vary considerably both within and between countries, which makes it very difficult to compare estimates, even for similar types of facilities. The reasons are largely due to different legal requirements in different countries and to historical custom and practice, leading to variations in basic assumptions such as the anticipated decommissioning strategy and end state of the site, and to different approaches to dealing with uncertainties. While attaining harmonisation across national approaches to cost estimation may be difficult to achieve, standardising the way decommissioning cost estimates are structured and reported will give greater transparency to the decommissioning process and will help build regulator and stakeholder confidence in the cost estimates and schedules.
This booklet highlights the findings of the NEA Decommissioning Cost Estimation Group (DCEG) which recently studied cost estimation practices in 12 countries.
Towards Transparent, Proportionate and Deliverable Regulation for Geological Disposal
Workshop Proceedings, Tokyo, Japan, 20-22 January 2009
English, 196 pages, published: 03/03/10
NEA#6825, ISBN: 978-92-64-06092-0
Available online at: http://www.oecd-nea.org/rwm/pubs/2010/6825-towards-transparent.pdf
As part of its activities, the Regulators’ Forum of the NEA Radioactive Waste Management Committee has been examining the regulatory criteria for the long-term performance of geological disposal. In this context, it organised a workshop entitled “Towards Transparent, Proportionate and Deliverable Regulation for Geological Disposal”, which served to verify current status and needs. Participants included regulators, implementers, policy makers, R&D specialists and academics. Themes addressed included duties to future generations, timescales for regulation, stepwise decision making, roles of optimisation and best available techniques (BAT), multiple lines of reasoning, safety and performance indicators, recognition of uncertainties and the importance of stakeholder interactions. The workshop highlighted the significant amount of work accomplished over the past decade, but also identified important differences between national regulations even if these are not in contradiction with international guidance. Also highlighted was the importance of R&D carried out on behalf of the regulator. In addition to the contributed papers, these proceedings trace the numerous discussions that formed an integral part of the workshop. They constitute an important and unique documentary basis for researchers and radioactive waste management specialists.
A Common Objective, a Variety of Paths
Synthesis and Main Lessons:Third International Conference on Geological Repositories, Berne, Switzerland, 15-17 October 2007
English, 40 pages, published: 10/20/09
NEA#6385, ISBN: 978-92-64-99100-2
Available online at: http://www.oecd-nea.org/rwm/reports/2009/6385-Common-Objective.pdf
High-level political, governmental and regulatory decision makers, as well as representatives of economic and social groups and implementing organisations met in Berne, Switzerland to present and to reflect on their collective experience towards meeting the challenge of implementing national disposal projects for placing radioactive waste in deep geological formations. This summary highlights the main lessons to be learnt and final recommendations to assist future developments in national radioactive waste management programmes seeking to meet both technical and social imperatives of modern society.
A Common Objective, a Variety of Paths
Third International Conference on Geological Repositories, Berne, Switzerland, 15-17 October 2007
English, published: 10/16/09
NEA#6875, ISBN: 978-92-64-99101-9
Available online at: http://www.oecd-nea.org/rwm/reports/2009/6875-icgr2007.pdf
High-level political, governmental and regulatory decision makers, as well as representatives of economic and social groups and implementing organisations met in Berne, Switzerland to present and to reflect on their collective experience towards meeting the challenge of implementing national disposal projects for placing radioactive waste in deep geological formations. These proceedings include the papers presented at the conference as well as a summary which highlights the main lessons to be learnt and final recommendations to assist future developments in national radioactive waste management programmes seeking to meet both technical and social imperatives of modern society.
Approaches and Challenges for the Use of Geological Information in the Safety Case for Deep Disposal of Radioactive Waste
Third AMIGO Workshop Proceedings, Nancy, France, 15-17 April 2008
English, 76 pages, published: 10/09/09
NEA#6417, ISBN: 978-92-64-99090-6
Available online at: http://www.oecd-nea.org/rwm/reports/2009/AMIGO-3/index.html
A cornerstone of national decision making and societal acceptance of deep geological disposal of radioactive waste is confidence that such repositories can protect humans and the environment both now and in the future. The “safety case” is the synthesis of evidence, analyses and arguments that quantify and substantiate a claim that the repository will be safe after closure and beyond the time when active control of the facility is ensured. For deep geological disposal, studies of the geosphere form a principal component of the safety case. Geoscientific information is unique in that it can offer evidence and lines of reasoning that span geological timescales (millennia and even longer).
The NEA Approaches and Methods for Integrating Geological Information in the Safety Case (AMIGO) project addresses the collection and integration of geoscientific evidence, analyses and arguments that contribute to an understanding of long-term safety. The third and final AMIGO workshop on “Approaches and Challenges for the Use of Geological Information in the Safety Case” underscored that geoscientific information plays a fundamental role in safety assessments. It is also increasingly used in the wider context of the safety case to provide evidence and arguments for the intrinsically favourable properties of a site, including its long-term stability. No single geoscientific argument “proves” safety, but rather each supports some key element of the safety case and provides enhanced confidence in the safety case. The workshop also considered the links and feedback among the safety case; design, engineering and construction issues; and geoscientific investigations.
Considering Timescales in the Post-closure Safety of Geological Disposal of Radioactive Waste
English, 160 pages, published: 03/13/09
NEA#6424, ISBN: 978-92-64-06058-6
Available online at: http://www.oecd-nea.org/rwm/pubs/2009/6424-considering-timescales.pdf
A key challenge in the development of safety cases for the deep geological disposal of radioactive waste is handling the long time frame over which the radioactive waste remains hazardous. The intrinsic hazard of the waste decreases with time, but some hazard remains for extremely long periods. Safety cases for geological disposal typically address performance and protection for thousands to millions of years into the future. Over such periods, a wide range of events and processes operating over many different timescales may impact on a repository and its environment. Uncertainties in the predictability of such factors increase with time, making it increasingly difficult to provide definite assurances of a repository's performance and the protection it may provide over longer timescales. Timescales, the level of protection and the assurance of safety are all linked.
Approaches to handling timescales for the geological disposal of radioactive waste are influenced by ethical principles, the evolution of the hazard over time, uncertainties in the evolution of the disposal system (and how these uncertainties themselves evolve) and the stability and predictability of the geological environment. Conversely, the approach to handling timescales can affect aspects of repository planning and implementation including regulatory requirements, siting decisions, repository design, the development and presentation of safety cases and the planning of pre- and post-closure institutional controls such as monitoring requirements. This is an area still under discussion among NEA member countries. This report reviews the current status and ongoing discussions of this issue.
International Experiences in Safety Cases for Geological Repositories (INTESC) + CD-ROM
Outcomes of the INTESC Project
English, 76 pages, published: 11/06/09
NEA#6251, ISBN: 978-92-64-99103-3
Available online at: http://www.oecd-nea.org/rwm/reports/2009/nea6251-INTESC-eng.pdf
- Français: Expériences internationales des dossiers de sûreté pour les dépôts en formation géologique (INTESC) + CD-ROM
A “safety case” is the synthesis of evidence, analyses and arguments that quantify and substantiate a claim that a geological repository for radioactive waste will be safe after closure and beyond the time when active control of the facility can be ensured. The NEA project on International Experiences in Safety Cases for Geological Repositories (INTESC) analysed existing safety cases, and their elements, to provide an overview of progress during the last decade, to identify key concepts and to give insight into regulatory expectations on the contents and review of safety cases. This report documents the outcomes of the INTESC project. It takes account of the responses to a detailed survey of NEA member countries as well as the results of a technical workshop.
The project has shown that the purpose and concept of a safety case are generally understood, accepted and adopted by radioactive waste management programmes worldwide. Programmes are preparing safety cases in line with most of the elements suggested by the NEA, although there are some differences in interpretation and presentation. Some important trends are emerging, such as the use of safety functions and the role of a geosynthesis. Further development of some aspects and tools, such as quality assurance programmes and requirements management systems, can be expected as safety cases are further refined to support programmes moving towards implementation of geological disposal.
Natural Tracer Profiles Across Argillaceous Formations: The CLAYTRAC Project
English, 364 pages, published: 03/24/09
NEA#6253, ISBN: 978-92-64-06047-0
Available online at: http://www.oecd-nea.org/rwm/pubs/2009/6253-claytract-project-2009.pdf
Disposal of high-level radioactive waste and spent nuclear fuel in engineered facilities, or repositories, located deep underground in suitable geological formations is being developed worldwide as the reference solution to protect humans and the environment both now and in the future. An important aspect of assessing the long-term safety of deep geological disposal is developing a comprehensive understanding of the geological environment in order to define the initial conditions for the disposal system as well as to provide a sound scientific basis for projecting its future evolution. The transport pathways and mechanisms by which contaminants could migrate in the surrounding host rock are key elements in any safety case. Relevant experiments in laboratories or underground test facilities can provide important information, but the challenge remains in being able to extrapolate the results to the spatial and temporal scales required for performance assessment, which are typically tens to hundreds of metres and from thousands to beyond a million years into the future. Profiles of natural tracers dissolved in pore water of argillaceous rock formations can be considered as large-scale and long-term natural experiments which enable the transport properties to be characterised.
The CLAYTRAC Project on Natural Tracer Profiles Across Argillaceous Formations was established by the NEA Clay Club to evaluate the relevance of natural tracer data in understanding past geological evolution and in confirming dominant transport processes. Data were analysed for nine sites to support scientific understanding and development of geological disposal. The outcomes of the project show that, for the sites and clay-rich formations that were studied, there is strong evidence that solute transport is controlled mainly by diffusion. The results can improve site understanding and performance assessment in the context of deep geological disposal and have the potential to be applied to other sites and contexts.
Regional Development and Community Support for Radioactive Waste Management (web only)
Synthesis of the FSC National Workshop and Community Visit, Tengelic and Bataapati, Hungary, 14-17 November 2006
English, 78 pages, published: 10/16/09
NEA#6258, ISBN: 978-92-64-99102-6
Available online at: http://www.oecd-nea.org/rwm/reports/2009/6258-FSC-Hungary.pdf
In November 2006, Hungary hosted the 6th National Workshop and Community Visit of the NEA Forum on Stakeholder Confidence (FSC). Participants included institutional authorities, local residents and stakeholders, 11 mayors and more than 30 FSC delegates from 12 countries. The workshop focused on those factors that contribute either to the success or failure of the siting process for a radioactive waste repository. Experience gained in Hungary over the past two decades provided the context for the discussions. The workshop highlighted the role and modes of operation of local public oversight and information associations, which proved to be instrumental in reaching an agreement between the implementer and the local communities. The workshop included a visit to the community of Bátaapáti and the ongoing project site for an underground repository for short-lived, low- and intermediate-level radioactive waste (LILW).
Stability and Buffering Capacity of the Geosphere for Long-term Isolation of Radioactive Waste: Application to Crystalline Rock
Workshop Proceedings, Manchester, United Kingdom, 13-15 November 2007
English, 304 pages, published: 03/20/09
NEA#6362, ISBN: 978-92-64-06056-2
Available online at: http://www.oecd-nea.org/rwm/pubs/2009/6362-stability-buffering.pdf
Geological settings selected as potential host formations for the deep geological disposal of radioactive waste are chosen for, among other assets, their long-term stability and buffering capacity against disruptive or destabilising events and processes. The NEA Integration Group for the Safety Case organised a workshop on geosphere stability to develop a better understanding of the scientific evidence and arguments that contribute to confidence in the geological stability for deep geological disposal.
These proceedings present the outcomes of a geosphere stability workshop, held in November 2007, that focused on crystalline and other types of hard, fractured rocks. The workshop underscored the fact that many such rocks are intrinsically stable environments that evolve extremely slowly and provide good buffering against external events and processes. There is a good understanding of the processes and events that can affect crystalline rocks and, although there is less confidence in predicting exactly when and where such events will occur and the volume of rock that will be affected, the extent of the impacts on a geological repository can be confidently addressed using bounding approaches supported by geological information from similar sites around the world.