CAJ | 학술논문

在百万千瓦级压水堆核电厂中为防止高压熔堆严重事故发生时发生高压熔喷(HPME)和安全壳直接加热(DCH)，参考 EPR 堆型在稳压器上额外设置严重事故卸压阀(SADV)，对主系统进行快速卸压.建立百万千瓦级压水堆核电厂事故分析模型，选取丧失厂外电叠加汽动辅助给水泵失效，一回路管道小破口以及丧失主给水三条典型严重事故序列，进行系统热工水力及卸压能力分析.计算结果表明：如果不开启严重事故卸压阀，三条事故序列在压力容器下封头失效时一回路压力均较高，有发生高压熔喷和安全壳直接加热的风险.根据严重事故管理导则开启严重事故卸压阀，可以有效降低一回路压力，三条事故序列均可以防止高压熔喷和安全壳直接加热发生.针对卸压阀阀门面积的影响进行分析，表明阀门面积减小到4.8×10－3 m2后下封头失效时 RCS 压力会有所增加，仍然能够满足 RCS 的卸压要求，且可延迟下封头失效时间.
재백만천와급압수퇴핵전엄중위방지고압용퇴엄중사고발생시발생고압용분(HPME)화안전각직접가열(DCH)，삼고 EPR 퇴형재은압기상액외설치엄중사고사압벌(SADV)，대주계통진행쾌속사압.건립백만천와급압수퇴핵전엄사고분석모형，선취상실엄외전첩가기동보조급수빙실효，일회로관도소파구이급상실주급수삼조전형엄중사고서렬，진행계통열공수력급사압능력분석.계산결과표명：여과불개계엄중사고사압벌，삼조사고서렬재압력용기하봉두실효시일회로압력균교고，유발생고압용분화안전각직접가열적풍험.근거엄중사고관리도칙개계엄중사고사압벌，가이유효강저일회로압력，삼조사고서렬균가이방지고압용분화안전각직접가열발생.침대사압벌벌문면적적영향진행분석，표명벌문면적감소도4.8×10－3 m2후하봉두실효시 RCS 압력회유소증가，잉연능구만족 RCS 적사압요구，차가연지하봉두실효시간.
To prevent high-pressure melt-spray event (HPME)and direct containment heat (DCH),dedicated severe accident depressurization valve (SADV)is added to the pressurizer with the reference of EPR design.The mechanism model for 1000 MWe PWR nuclear power plant is built and three sequences of TMLB’,SBLOCA and LOFW are selected to be investigated.Thermohydraulic and depressurization of RCS is analyzed,which shows that:without opening SADV,the RCS pressure is high enough to induce large risk of HPME and DCH when lower head of the RPV fails for the selected typical severe accident sequences;while with opening SADV according to severe accident management guidelines,the RCS pressure is low enough to prevent HPME and DCH for the selected typical severe accident sequences.The effect of SADV area is also analyzed,which shows that the RCS pressure will increase by decreasing the valve area to 4.8e-3 m2 when lower head of the RPV fails; while the criterion for RCS depressurization is still satisfied and the time for lower head of the RPV failure is also delayed.