Case Study: Diablo Canyon Power Plant, California (USA). [An Introduction to Probabilistic Fault Displacement Hazard Analysis in Site Evaluation for Existing Nuclear Installations]

The Diablo Canyon Power Plant (DCPP), which generates electricity from two 1 100 MW pressurized-water reactors, is located on the central California coast, approximately half-way between the Los Angeles and San Francisco metropolitan areas. The recognition in 2008 of an alignment of small earthquakes led to the discovery of the Shoreline fault, a strike-slip fault that is located offshore less than one kilometre from DCPP. As part of the initial investigations to understand the seismic hazard and risk of the Shoreline fault to the DCPP, a PFDHA was conducted for the plant's auxiliary saltwater intake pipes, which are safety-related structures that were determined to be vulnerable to small permanent ground displacements. This case study summarizes the PFDHA conducted for DCPP, which implemented the hazard formulation for strike-slip faulting environments developed. The case study presents an example application of the PFDHA methodology for distributed fault displacement hazard to a specific, safety-related engineered structure at an existing nuclear installation located away from the principal fault trace.