PSA Application for UK HPR1000 ALARP Demonstration

Abstract

UK version of the Hua-long Pressurised Reactor (UK HPR1000), designed by China General Nuclear Power Corporation (CGN), has been successfully completed the Generic Design Assessment (GDA), with the issue of a Design Acceptance Confirmation (DAC) from Office for Nuclear Regulation (ONR) and a Statement of Design Acceptability (SoDA) from the Environment Agency on 7 February 2022. In the UK GDA process, one of the main fundamental requirements is that the nuclear safety risk should be reduced to ALARP (As Low As Reasonably Practicable). During the UK HPR1000 design process, Probabilistic Safety Assessment (PSA) has been widely used as a key tool to inform the design and evaluate risk levels, and to demonstrate that the nuclear safety risk has been reduced to ALARP. The process of PSA ALARP demonstration is established in accordance with the methodology that reflects the UK context requirements and consistent with relevant good practice. The process is fully applied by using PSA to systematically review the risk insights and to support other topic areas. After the systematic review of PSA risk insights from internal events Level 1 PSA, internal fire Level 1 PSA, internal flooding Level 1 PSA, external hazards Level 1PSA, external flooding Level 1 PSA, seismic PSA, Spent fuel pool PSA and Level 2 PSA, the related conservatisms, potential design improvements have been identified and addressed. Current UK HPR1000 PSA results and risk insights show that the risk level of UK HPR1000 design is relatively low and the risk of UK HPR1000 design has been reduced to ALARP in GDA stage.