Standardized Plant Analysis Risk Model and Other Probabilistic Risk Assessment Lessons Learned from Mitigating Systems Performance Index Development and Implementation

The Standardized Plant Analysis Risk (SPAR) Model Development Program has played an integral role in the Accident Sequence Precursor (ASP) Program analysis of operating events. In a complementary fashion, one of the objectives of the ASP Program is to use plant operating experience results and insights for feedback to the SPAR models, as well as to licensee probabilistic risk assessment (PRA) models. In addition, the use of SPAR models as part of the ASP Program and the significance determination process (SDP) Phase 3 evaluations also provides the opportunity for review and benchmarking of the SPAR models against the licensee PRA models in cases where the licensee also provides risk-related input to the ASP and SDP evaluations.