CSPACE for a simulation of core damage progression during severe accidents

다국어 초록 (Multilingual Abstract)

CSPACE (Core meltdown, Safety and Performance Analysis CodE for nuclear power plants) for a simulation of severe accident progression in a Pressurized Water Reactor (PWR) is developed by coupling ofverified system thermal hydraulic code of SPACE (Safety and Performance Analysis CodE for nuclearpower plants) and core damage progression code of COMPASS (Core Meltdown Progression AccidentSimulation Software). SPACE is responsible for the description of fluid state in nuclear system nodes,while COMPASS is responsible for the prediction of thermal and mechanical responses of core fuels andreactor vessel heat structures. New heat transfer models to each phase of the fluid, flow blockage, coriumbehavior in the lower head are added to COMPASS. Then, an interface module for the data transferbetween two codes was developed to enable coupling. An implicit coupling scheme of wall heat transferwas applied to prevent fluid temperature oscillation. To validate the performance of newly developedcode CSPACE, we analyzed typical severe accident scenarios for OPR1000 (Optimized Power Reactor1000), which were initiated from large break loss of coolant accident, small break loss of coolant accident, and station black out accident. The results including thermal hydraulic behavior of RCS, coredamage progression, hydrogen generation, corium behavior in the lower head, reactor vessel failure werereasonable and consistent. We demonstrate that CSPACE provides a good platform for the prediction ofsevere accident progression by detailed review of analysis results and a qualitative comparison with theresults of previous MELCOR analysis.

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