中国氦冷固态实验包层模块In-box LOCA事故分析研究

摘要

China Helium Cooled Ceramic Breeder Test Blanket Module (CN HCCB TBM) will be tested on ITER equatorial port #2, and there will be nuclear reaction between fusion neutrons and material inside TBM during the test, which will produce considerable amount of tritium and other radioactive isotopes. Considering ITER operation and nuclear safety for the public and workers, the safety analysis must be carried out before its test on ITER. In this paper, the MELCOR model was created based on CN HCCB TBM and its helium cooling system (HCS). In-box LOCA was chosen to be investigated. The key parameters of break size, relief tank volume, and isolation time were performed sensitivity analyses. The analysis results show that the pressure limit of TBM box (4 MPa) was exceeded during all-channel break, however, the pressure limit of box was not exceeded during one-channel or five-channel break. Installing relief tank and reducing the isolation time were effective ways to control the box pressure.%中国氦冷固态实验包层模块(CN HCCB TBM)将在ITER 2号窗口进行测试,在测试期间,聚变中子和TBM内部材料发生核反应,产生氚和其他放射性物质.考虑到ITER的运行和工作人员与公众的安全,在进入ITER测试之前需要进行事故安全分析.本文应用MELOCR对HCCB TBM及其氦冷系统(HCS)进行建模,开展了TBM增殖区冷却板流道破口事故(In-box LOCA)安全研究,并对泄压罐体积,破口面积,隔离阀关闭延迟时间等关键参数进行敏感性分析.结果表明:在保守假设流道全破裂的工况下,box压力超过其压力限值4 MPa,而单根流道和5根流道破裂的工况下,box均未超过其压力限值;安装泄压罐和改变隔离阀关闭延迟时间能够有效的控制box压力.