Development and Application of CAP1400 Probabilistic Safety Assessment

A full scope Probabilistic Safety Assessment (PSA) is developed for CAP1400 and some design modification was performed based on the CAP1400 PSA insights. In this paper, a brief introduction of CAP1400 PSA is presented, including analysis method, procedure, results and insights obtained and design improvements. The CAP1400 PSA includes internal events level 1 PSA, low power and shutdown PSA, level 2 PSA, level 3 PSA, internal fire PSA, internal flooding PSA, seismic margin analysis and seismic PSA, etc. The CAP1400 PSA is developed based on PSA methods acknowledged internationally and in compliance with the requirement of PSA related standards, such as ASME PSA standards and Chinese PSA standards. The design improvements derived from PSA results are also introduced in this paper, including design change of passive core cooling system (PXS), diverse design of instrument and control system, design change of in-vessel retention (IVR) of molten core debris, installation of very early warning fire detection system and design change of flooding protection of PXS valves.