THE CMT SIMULATION ON THE LARGE IMPASSIVE PWR WITH RELAP 5

抄録

Since Three Mile Island accident, the small break losing of coolant accident (SBLOCA) was identified as the important accident during the nuclear reactor operating. Many facilities were built to understand the phenomena during SBLOCA and worked to improve the safety of 2nd generation nuclear power plant (NPP). Now the days, the core makeup tank （CMT）, used to be a coolant source during the high-pressure phase in SBLOCA, had been introduced with the ideal of passive core coolant system (PCCS) into 3rd generation NPP. The earlier study focus on the automatic depressurization system (ADS), accumulator (ACC), and passive residual heat removal system (PRHR). In our simulation on the advanced plant experiment (APEX), the integral test facility of AP-1000, and the advance core-cooling mechanism experiment (ACME), the integral test facility of CAP-1400, by RELAP 5 MOD3.2 shows that the main error on the core makeup tanks (CMTs) injection phase is an important error source in the SBLOCA simulation of PWR with PCCS. In the high-pressure phase of the nature-cycle, the phenomena in the CMT and Pressure Balance Line (PBL) loops lead the CMT level decrease slowly. In this study, we tried to identify the main leading phenomenon.