수직 전열관 외벽 열전달 계수 실험 데이터를 활용한 MARS-KS 코드 응축 모델 검증

Abstract

After Fukushima nuclear power plant accident, importance of passive safety systems was emphasized. Among them, the Passive Containment Cooling System (PCCS) is depressurize by steam condensation to maintain the integrity of containment in the accident such as the loss of coolant. Steam is cooled and condensed through the pipe wall which coolant flows. Steam moves to the pipe with noncondensable gas, so noncondensable gas builds up near the pipe. And it disturbed steam condensation. In this study, two steam condensation experiments in the presence of noncondensable gas are simulated by MARS-KS code. The calculations of MARS-KS and experiment results were compared to verify the condensation model in MARS-KS code. MARS-KS code is underestimate the heat transfer coefficient even if calculation shows a tendency like experiment. And when the result of MIT experiment and JNU experiment are compared, the calculation of code shows that MARS-KS code does not consider about geometry of experiment. As the results, condensation heat transfer model in MARS-KS code about steam condensation in the presence of noncondensable gas needs to be improved about effects of test geometry.