The International Intercomparison and Harmonisation Project
on Demonstrating the Safety of Geological Disposal
The first part of the GEOSAF project commenced in 2008 and had its last plenary meeting in May 2011. On the request of the participants a follow- up project was planned. During the meeting, it was agreed to set up a follow-up project called GEOSAF Part II as 3 years activity.
GEOSAF provides a forum to exchange ideas and experiences in developing and reviewing the safety case for geological disposal facilities. It also aims at providing a platform for knowledge transfer. With more countries contemplating embarking on nuclear power, and existing producers seeking to define national policies and strategies aimed at covering all elements of the fuel cycle, such a platform is considered not only appropriate, but relevant. There is also a need to maintain existing knowledge bases.
The project focuses on the safety case for geological disposal facilities, a concept that has gained in recent years considerable prominence in the waste management area and is addressed in several international safety standards.
GEOSAF pays particular attention to the evolution of the safety case with the development of a disposal project and particularly to the regulatory expectations on the development of the safety case in order to enable decisions to be made as part of the licensing process. Whilst the project addresses the elements of the safety case necessary for safety demonstration and the work necessary to support the various safety arguments, it also considers the process of reviewing and evaluating the safety case by regulatory authorities and the needed resources. That is the reason why the project involves regulatory authorities, technical safety organizations and waste management organizations responsible for the development and operation of geological disposal facilities.
GEOSAF addresses geological disposal as defined in the IAEA Safety Requirements on Disposal of Radioactive Waste (SSR-5), as a “facility constructed in tunnels, vaults or silos in a particular geological formation (e.g. in terms of its long term stability and its hydrogeological properties) at least a few hundred meters below ground level. Such a facility could be designed to accept high level radioactive waste (HLW), including spent fuel if it is to be treated as waste. However, with appropriate design a geological disposal facility could receive radioactive waste of all types”.
In practice GEOSAF is developed on the foundation of the work of the European Pilot Study (French Nuclear Safety Authority initiative) and on two IAEA safety standards: the Specific Safety Requirements on Disposal of Radioactive Waste (SSR-5) and the Specific Safety Guide on the Safety Case and Safety Assessment for Radioactive Waste Disposal (SSG-23).
Furthermore, GEOSAF carried out an exercise on the development and technical review of a real national case for demonstrating the feasibility of a geological disposal in a clay formation. The objective of this exercise was to contribute to the development of a questionnaire devoted to review the Safety Case that would structure a foreseen IAEA review procedure.
During the course of the project, noting that, after decades of long term safety development, little work was undertaken internationally to develop a common view on the safety approach related to the operational phase of a geological disposal. GEOSAF therefore initiated, as part of a pilot study, a specific programme of work on the safety of the operational phase. As for long-term safety, the objective was to work towards harmonizing the approach in demonstrating the safety of the operational phase and its subsequent reviewing. The outcome of this pilot study is documented in a companion report which served as a basis of a further work.
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