基于RELAP5的中国氦冷固态包层真空室外破口瞬态特性分析

Transient Characteristic Analyses of Ex-vessel Coolant Pipe Break for Chinese Helium-cooled Solid Breeder TBM Based on RELAP5 Code

利用RELAP5/MOD3.4对中国氦冷固态包层、氦气冷却剂回路和二次侧水冷系统进行建模和系统热工水力安全评价。依据ITER事故分析制定的事故序列,对设计基准真空室外破口进行了瞬态分析,并对比了不同破口位置、面积和停堆方式对第一壁的影响。结果表明:真空室外破口发生在风机的下游较上游危险,且小破口较大破口更危险;若真空室外破口同时包层第一壁破口,也可通过自然循环和辐射换热带走衰变热冷却包层;真空室外破口事故中采用聚变停堆系统的3s停堆方式,可避免第一壁熔化。

Chinese helium-cooled solid breeder（CH HCSB） test blanket module（TBM） with helium cooling system and secondary cooling water system was modeled and thermal-hydraulic behavior and safety performance of the system were assessed using the RELAP5/MOD3.4 code.According to the accident sequences of ITER accident analysis specification for TBM,the transient analysis of the design basis ex-vessel coolant pipe break accident was carried out.The influences of different break locations,leak areas and plasma shutdown processess on the first wall of TBM were compared.The results indicate that it is much more danger when the pipe break occurs at the downstream side of the helium circulator compared with that at upstream side.The results also show that the accident consequence is worse in case of smaller area break than that in case of larger area break.In case of much more severe accident that the ex-vessel break leads to the break of TBM the first wall,the results reveal that the decay heat can be removed to cool down TBM by natural circulation and radiation.The first wall melting can be avoided if the method to shutdown plasma within 3 seconds in case of ex-vessel break is adopted.