Insights from PSA Comparison in Evaluation of EPR Designs

The paper describes the outcome of a limited probabilistic safety assessment (PSA) comparison on the following EPR designs: Olkiluoto 3 Nuclear Power Plant (NPP) in Finland, Flamanville 3 NPP in France, UK EPR design, and U.S. EPR design. The objective of this PSA comparison was to identify differences in the modeling aspects and results of EPR PSAs, as well as to assess the rationale for these differences. The comparison covered various types of initiators challenging a broad scope of safety functions. Insights from the EPR PSA comparison and rationale for the differences originated from modeling assumptions, applied reliability data, designs, and operational aspects. The EPR designs chosen for comparison represents various design and licensing stages, as well as level of detail, which gives the main rationale for the identified differences. The outcomes and lessons learned from the EPR PSA comparison have been used to facilitate the regulatory reviews and assessment work of various EPR designs and to enhance the scope, level of detail, and quality of EPR PSA models and documentation.