用ICARE/CATHARE分析百万千瓦级PWR严重事故堆芯行为

【作者】 孙成林；

【导师】 张应超； 季松涛；

【作者基本信息】 中国原子能科学研究院 ， 核能科学与工程， 2006， 硕士

【摘要】 当前我国正积极发展核电，随着核电厂数量的增加，核电安全问题就显得越来越重要，而安全分析技术(DBA以及严重事故)是确保核电安全的技术基础。本文成功的在Linux系统下安装了ICARE／CATHARE程序，并建立了900MWe核电厂的计算模型。分析了该核电厂大破口失水加全厂断电事故序列和小破口失水加全厂断电事故序列的堆芯破坏过程，并研究了小破口失水加全厂断电事故序列的缓解措施及其有效性。900MWe核电厂大破口失水加全厂断电事故序列的分析表明：500s时开始锆水反应，1700s时堆芯内的燃料开始损坏，2400s堆芯上部全部损坏、坍塌并产生了大约270kg的氢气。对破口位置的敏感性分析表明，冷端大破口失水事故要比热端大破口失水事故进展更快、后果也更严重。小破口失水加全厂断电事故序列的分析结果表明小破口失水事故进程比大破口失水进程相对较慢。在大约2400s时开始堆芯裸露，13000s左右堆芯开始出现损坏，15000s计算结束。在小破口失水事故分析中还对几种事故缓解措施进行了分析，结果表明，如果能在事故开始后半小时开始注水，堆芯水位将很快恢复，能在堆芯建立冷却，并阻止堆芯损坏；如果在事故后堆芯出口蒸汽温度超过650℃(约2700s)时开始注水，堆芯内只有少量包壳发生氧化，但随后堆芯水位很快恢复，堆芯温度降低，也可以保持堆芯的完整性。严重事故分析有助于更加详细地了解堆芯破坏过程中所发生的物理、化学、力学行为、热工水力行为等现象。为研究事故的预防和缓解措施，给出最佳的干预时间和干预方式提供技术基础。本文应用ICARE／CATHARE程序研究900MWe核电厂的堆芯破坏机理，该工作是国内的首次成功尝试，对今后该程序的进一步推广应用以及中法继续在严重事故领域的合作都具有重要的促进作用。更多还原

【Abstract】 The safety of nuclear power plant (NPP) should be paid much attention due to an ambitious development policy in China. Severe accident analysis is one of the essential techniques to assure safety of NPP. The report describes an application of ICARE/CATHARE code to a 900MWe PWR, including the main aspects as follows:Installation of ICARE/CATHARE code under Linux operating system;Modeling of 900MWe PWR;Analyzing accident sequences of LBLOCA and SBLOCA with station blackout, including investigation of the mitigation measures under SBLOCA.The analysis of LBLOCA shows that oxidation of Zr begins at about 500s. The core begins to damage at 1700 seconds and the upper part of the core is observed full damage at 2400s while 270kg hydrogen is generated. A sensitivity study shows that the process of the accident with a cold leg break is faster than that with a hot leg break. The analysis shows that the progress of SBLOCA with station blackout sequence is slower than that of LBLOCA. The core uncovers at about 2400s and begins to damage at 13000s. The analysis shows that the core keeps intact if the inject system could put into operation at about half an hour after initialization of the accident. Whereas, only slight oxidation is found at upper of the core if the inject system could put into operation when the vapor temperature of the core outlet exceeds 650℃(about 2700 seconds).更多还原