包壳相关行为对严重事故进程的影响分析

严重事故工况下,锆合金包壳与水剧烈反应,产生氢气并释放大量热量,会导致堆芯熔化。熔化的锆合金包壳发生共晶反应,二氧化铀与二氧化锆在低于其熔点时发生熔化,将对堆芯熔毁事故进程产生显著影响。本文使用一体化严重事故分析程序,研究百万千万级压水堆核电站发生全场断电叠加破口事故下,包壳行为对严重事故进程的影响。分析结果表明,锆水反应精细化计算模型修改后,全场断电叠加大破口事故下堆芯产氢量减少24.1 Kg；共晶反应能够加速熔融物向下封头迁移同时延长堆芯失效时间。

The Effect Analysis of cladding related behavior under severe accident

Under severe accident conditions, zirconium alloy cladding reacts with water violently to produce hydrogen and release a lot of heat, which will lead to core melting. The eutectic reaction takes place in the molten zirconium alloy cladding, and the fusion of uranium dioxide and zirconia below their melting point will have a significant impact on the process of core meltdown accident. In this study, the integrated severe accident analysis program code is used to study the influence of cladding behavior on the process of severe accident in the event of the full power outage superposition break accident in the whole plant of the 1 000 MWe nuclear power plant. The analysis results show that after the refined calculation model of zirconium water reaction is modified, the hydrogen production in the core is reduced by 24.1 kg under the superposition of full power outage and large break accident; eutectic reaction can accelerate the migration of melt to the lower head, prolong the time of core failure.