The main objective of the Working Group on Risk Assessment (WGRISK) of the Nuclear Energy Agency (NEA)/Committee on the Safety of Nuclear Installations (CSNI) is to advance the probabilistic safety assessment (PSA) understanding and to enhance its utilisation for improving the safety of nuclear installations. Due to its disciplined, integrated and systematic approach, PSA is now considered as a necessary complement to traditional deterministic safety analysis.
This report provides a description of the PSA activities in the member countries at the time of the report writing. Since there have been significant new developments in PSA since the last version, and considering the interest and usefulness of the previous versions, WGRISK initiated the development of an updated version of the report in early 2011.