Partner und Internationale Organisationen
(Englisch)
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NIREX (UK), ISTec (D), ANDRA (F), ENRESA (E), ONDRAF (B), SERCO Ltd. (UK) (formerly AEA Technology), NAGRA (CH), POSIVA (FIN), SKB (S)
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Abstract
(Englisch)
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Repositories for nuclear waste are expected to produce gases as a result of a variety of chemical, microbiological and radioactive decay processes. Assessment of the impact of the generation and migration of gas is recognised to be an important element of any safety case for the disposal of such wastes. A recent report, based on the proceedings of a joint NEA/EC workshop, provides a foundation for improving the treatment of gas issues in safety assessments. This thematic network will build on the existing approaches for producing safety cases for deep geological disposal, utilising the expertise of the European nuclear industry, academia, regulators and other specialists, in order to:
(a) summarise the present treatment of gas in safety assessments and
(b) evaluate these approaches and provide guidance for future safety assessments.
To evaluate the present treatment of gas issues in safety assessments of deep geological repositories for nuclear waste, and to improve the translation of scientific information on these issues into safety arguments for such repositories. Utilising the expertise of the nuclear industry, academia, regulators and other specialists in achieving this evaluation, to produce a project report that documents the current approaches used in dealing with gas issues in safety assessments and the strengths and limitations of these approaches.
A discussion report summarising current approaches to the treatment of gas issues in the context of a safety case will be produced after 12 months.
A workshop will obtain feedback on this report and define a way forward. Based on the workshop discussion and feedback received, a final report will evaluate the present treatment of gas issues in safety assessments, and will discuss the strengths and limitations of these approaches.
The GASNET programme will link together the experience of eight European organisations responsible for preparing safety cases for deep repositories for various types of waste, using various engineered barriers (e.g. bentonite and cement), in various types of geological media (e.g. crystalline rock, clay and salt).
The network will explore and compare the approaches used to address gas-related issues in safety cases. Initially a discussion report will be produced summarising the approach adopted by each participating organisation.
This first report will be used as a basis for a workshop, to discuss issues such as:
- The importance of good communication
- Demonstrating conservatism in a robust safety assessment
- The timescale of gas generation in relation to repository evolution in the immediate post-closure period
- Design measures that could minimise gas generation and mitigate its consequences
- Representation of gas generation and migration in mathematical models
- The importance of optimisation and iteration Expertise of academia, regulators and other specialists will be sought as a key input to this workshop.
The discussion and feedback from this workshop will be developed to produce a final report as an output from the Network, which should provide valuable guidance for the future, both for participating organisations and for organisation on other EU nations that are at a less advanced state of development in dealing with safety issues for geological disposal.
It is proposed that the project be divided into three work packages as follows:
1. Summary of published and current gas safety assessments
2. Workshop on gas issues in safety assessment
3. Final report on gas issues in safety assessment.
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