Integration and Management activities of the Integration Group for the Safety Case (IGSC) are designed to address the issue of "how to synthesize knowledge and build confidence in safety."
A "safety case" may be broadly defined 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 depository facility. Topical seminars have been held on this topic during the third and fifth IGSC meetings. This is one of the IGSC's most important activities; as such, a policy paper for a general readership (available in English and French) has been published. An international symposium on the safety case was held in January 2007. Symposium participants examined the evolution of the safety case concept (both internationally and in national programmes) and its role in societal dialogue and decision-making processes. The proceedings of the symposium are currently in preparation.
The Nature and Purpose of the Post-Closure Safety Cases for Geological Repositories – 2012 Update (to be published)
Underground research laboratories (URLs) have an important and multi-faceted role in repository development. They provide a realistic environment for conducting scientific assessments and demonstrations. In areas such as demonstrating operational safety, acquiring geological information at a repository scale and in constructional and operational feasibility, only URLs can provide reliable in situ data. Many nuclear waste management programmes have advanced their repository designs and are moving towards implementation of disposal. These programmes have made extensive use of URL for research and development work including important developments in optimisation of design elements; and have conducted or planned detailed site investigations through site-specific URLs. Other radioactive waste management programmes are commissioning or considering new URLs as integral components of staged implementation of geological disposal. New URLs are also being planned for to further optimize the implementation of geological disposal. A URL brochure has been developed to summarize the URL activities of the NEA member countries.
Reversibility refers to decision-making during project implementation. It involves ensuring that the implementation process and technologies maintain flexibility so that reversal or modification of one or a series of previous decisions may be possible without excessive effort. Retrievability is the ability to retrieve emplaced waste or entire waste packages. While retrievability is an intrinsic part of the concept of waste storage, it is not part of the basic, long-term safety concept of waste disposal in a final repository. Waste should never be emplaced in a repository if the long-term safety case is not robust without reliance on retrievability. Retrievability provisions also provide additional flexibility during operation.
In 2007, the Radioactive Waste Management Committee (RWMC) of the NEA started a project to study the issues of reversibility and retrievability (R&R) in geological disposal of radioactive wastes. The project, ended in 2011, has developed a leaflet and a full R&R report. For more information, visit the R&R web page
The Approaches and Methods for Integrating Geologic Information in the Safety Case (AMIGO) programme aims to advance current understanding of the the safety case, identify where future work is needed and reduce uncertainties. It will contribute to the development of methods for geosphere representation in a safety case. A first AMIGO workshop on Geological Disposal: Building Confidence Using Multiple Lines of Evidence took place on 3-5 June 2003 in Switzerland. A second AMIGO workshop on the Linkage of Geoscientific Arguments and the Line of Evidence supporting the Safety Case took place on 20-22 September 2005 in Toronto, Canada. A third workshop, addressing Approaches and Challenges for the Use of Geological Information in the Safety Case was held in April 2008, hosted by the French Agence nationale pour la gestion des déchets radioactifs (ANDRA). The aim of the workshop was to facilitate the exchange of information and in-depth discussions on the collection and integration of all types of geologic information in repository siting and design, performance assessment models and the overall safety case for the deep disposal of radioactive waste. A compendium detailing the current state of geoscientific data and its use in safety cases is now in prepartion. The report is based on the responses to a questionnaire distributed in 2005-6.
Phase one of the Integrated Performance Assessments of Deep Repositories (IPAG-1) produced a report emphasising the lessons learnt from performing IPAs. Phase 2 of IPAG (IPAG-2) focused on the experience of regulatory reviews of integrated performance assessments (IPAs). The third phase of IPAG dealt with Establishing and Communicating Confidence in the Safety of Deep Geologic Disposal: Approaches and Arguments.
The overall goals of this initiative are to analyse existing safety cases or elements of safety cases that are under development, and to identify key concepts; to provide a clear overview of the progress that has been made in the last decade; and to provide for an assessment to identify best practice in this area. Following the distribution of a detailed questionnaire in 2006, information from 17 member organisations has been collected. The report, which is currently in preparation, will help clarify actual differences and similarities in safety cases.
An INTESC workshop took place on 1-3 October 2007 at the NEA offices in Paris, France. The aim of the workshop was to assess, based on the preliminary findings of the INTESC questionnaire results and the outcomes of other current NEA initiatives, the current state of the art in the development of safety cases and where areas of agreement and disagreement may exist. Workshop participants also sought to identify and understand issues that may need further work by the IGSC.
Processes and events affecting the evolution of deep repositories for long-lived radioactive waste are characterised by a wide range of timescales and frequencies. The IGSC organised a workshop on the Handling of Timescales in Assessing Post Closure Safety in Paris in 2002. A policy paper in English and French was issued in 2004. A IGSC topical session in 2005 also examined the issue, which led to the release of a state-of-the-art report Consideration of Timescales in Post-closure Safety of Geological Disposal of Radioactive Waste in 2006.
Disposal of long-lived radioactive waste in engineered facilities built in stable, deep geological formations is the reference means for permanently isolating the waste from the biosphere. Although this management method is conceived to be intrinsically safe and final, i.e. not depending on the presence and intervention of man for fulfilling its safety goal, there is no intention to forgo, at any time, knowledge and awareness either of the repository or of the waste that it contains. As repository developing is reaching industrial maturity, means are being studied to maintain indirect forms of oversight once the repository is closed. These include monitoring, applying safeguards, maintaining records and ultimately preserving memory. The Records, Knowledge and Memory (RK&M) project, by organizing a series of workshop to address different aspect of preserving RK&M. For more information of this project, visit the RK&M web page.
International peer reviews of national radioactive waste management programmes have been increasingly carried out under the aegis of the RWMC over the past decade. Peer review organized by the NEA systematically examines and assesses some specific aspects of a national waste management programme. The ultimate goal of a peer review is to assist the requesting member country to adopt the best practices and to comply with established principles.
Last reviewed: 26 June 2013