Pilot Study Incorporating Shake Table Tests and Earthquake Experience Data to Develop Equipment Capacities for Use in Fragility Calculations

Seismic capacities for use in seismic probabilistic risk assessments (SPRAs) or seismic margin assessments (SMAs) at nuclear power plants (NPPs) are typically evaluated using shake table test (STT) data, earthquake experience, or analysis. Each of these methods have conventionally been treated as mutually exclusive (e.g., a capacity is developed based on STT or earthquake experience data but not both). However, since both STT and earthquake experience data are based on empirical equipment performance, it may be feasible to develop capacities based on the combined experience to achieve a more complete understanding of the equipment capacity. Recent advances in earthquake experience-based methods (e.g., Electric Power Research Institute (EPRI) 3002011627 (2017a)) provide a convenient framework for incorporating test data with earthquake experience data. In 2014, EPRI initiated a multi-phase project to review the available earthquake experience data (eSQUG v2.7, EPRI (2017b)) and apply improved Bayesian statistical methods to update the function-after seismic capacities of sixteen equipment classes. Updated best-estimate median capacities increased by up to 37% over the previous median in-structure spectral acceleration capacity of 4.8g. Phase III of the project (EPRI 3002015996 (2019)) evaluated the use of STT data to further improve the capacity from experience data for a sample class (Control Panels). This paper summarizes the main findings of that pilot study, including addressing several important differences between the STT and earthquake experience data types, and identifying potential challenges in the collection and use of different STT data sets.