IPSN Level 2 probabilistic safety assessment of 900 MW PWRs.

J.M. Evrard, B. Chaumont, B. Roussel, M. Durin, Fith international conference on probabilistic safety, 27/11-1/12 1999, Osaka.

A Level 2 Probabilistic Safety Assessment (PSA) of 900 MW PWRs is underway in IPSN with the following objectives: (1) to contribute to evaluate the safety level of reactors and identify the main risk scenarios; (2) to estimate the benefits of accident management procedures and guides to reactor safety and (3) to provide more quantitative judgement elements about the advantages of any modifications to reactor design or operation. This study should also help to guide research and development programs in the severe accident field, in order to reduce uncertainties on topics which have been identified as being most important in terms of risk to man and environment. Some benefits in terms of knowledge and tools for emergency management are also expected. The study comprises two main steps : a preliminary version, based on the results of the level 1 PSA published in 1990 and limited to initial power states, which is now complete, and a final version which will cover all the initial states of the reactor and will be based on the results of the ongoing updated level 1 PSA and of the fire PSA performed in IPSN.