Changes in PSA Models to Support the Licensing of Advanced Non-Light Water Reactors

The role of PSA in the licensing of nuclear power plants has changed significantly over the last 40- years. For plants licensed in the USA in the 1970's and 1980's, there was no requirement for a PSA as part of the plant's licensing basis. Currently in 2022, a PSA is required as part of risk-informing the licensing basis for new LWRs. For example, the PSA developed for the design certification of the Vogtle 3 & 4 plants in the United States consisted of internal events, internal fire, internal flood, and seismic hazards. The PSA developed for Vogtle 3 & 4 followed the current approach as embodied in the 2009 ASME/ANS PRA Standard and developed initiating events that could result in core damage or large early release of fission products to the environment.