Probabilistic safety assessment for research reactors - Proposal for an international RTD project

Full text: Currently, there are more than 250 Research Reactors (RRs) being in operation in more than 50 countries (many of them being EU Member States and Accession Countries). Those reactors are mainly used to provide research in the field of the use of ionising radiation as well as for the production of different radioisotopes which are vital for our society not only because of their unique use in the medical services, but also because of many other well known radioisotopes applications such as education and training, basic and applied physics, radiochemistry and environmental research. Nowadays the question about the risk and benefits from the operation of RRs is often raised by politicians, regulatory bodies, general public and different non-governmental organisations. It is understandable that most people would not like to tolerate any risk from a technology, but would appreciate receiving its benefits. It is a task of the scientists and the regulatory bodies in each country to provide all the measures and necessary information which are needed to justify the safe operation of the RRs and to explain why society needs these reactors. One of the safety verification tools which is internationally well developed is the so-called Probabilistic Safety Assessment (PSA). Originally developed some 30 years ago to assess the safety of Nuclear Power Plants (NPPs), it can nowadays easily be utilised to assess also the safety of the different types and utilisations of RRs. If its methods and data are defined and applied in a consistent manner, the qualitative and quantitative results of a PSA can provide a valuable input to any decision making process which considers the risks and benefits from the operation of a RR. The results from such analyses can be centrally used to optimise the decision making process and to ensure that all safety issues at a RR facility are dealt with an importance which is commensurate with their significance. Further, PSA proved to be an assessment method whose results can easily be understood and communicated to the general public. Although there is much practical experience with PSA for NPPs, there is little coordinated experience with RR applications. In the light of a relatively large fleet of small and medium power level RRs in Europe and international that are more and more approaching the end of their recommended lifetime, and the planning and design of a few new RRs, the proposed international RTD project should significantly contribute to resolving these shortcomings. The study aims at both theoretical RTD work and practical PSA case studies. (author)