一体化小堆失水事故响应及后果研究

Study on Response and Consequence of Loss of Coolant Accident in Integrated Small Reactor

为全面分析一体化小型模块式反应堆(简称小堆)失水事故,基于RELAP5程序建立了包括堆芯、主回路和安全壳在内的整体分析模型,对堆芯和安全壳瞬态响应及环境放射性后果进行计算分析,结果表明事故后果满足小堆安全审评原则规定的验收准则。此外,提出了改进的紧贴式安全壳方案及可选的参数配置,计算结果表明采用改进方案可使一回路和安全壳压力很快达到平衡,更早终止破口流量,从而减少一回路失水量和放射性释放量,提升堆芯安全性并降低事故剂量后果,壳外水池容量可保障安全壳长期冷却。研究成果可为一体化小堆工程应用和安全壳设计提供参考依据。

The overall analytic model including the core,primary loop and containment was established base on RELAP5 code to fully analyze the Loss of Coolant Accident(LOCA)for the integrated small modular reactor(or small reactor for short).The transient response of the core and containment as well as the radiological consequence for the environment were calculated and analyzed.The results showed that the accident consequences met the acceptance criteria stipulated in the small reactor safety review principle.Besides,the improved scheme of close-fitting containment and the optional parameter configuration were proposed.The calculation results show that with the improved scheme,the pressure balance of the primary loop and containment can be achieved very shortly and the break flow is terminated earlier,so the loss of primary coolant and the radiological release are reduced.The core safety is enhanced,and the dose consequence of the accident is decreased.Meanwhile,the long-term cooling of containment can be ensured by the pool outside the containment.The research results can provide references for the engineering application and containment design of the integrated small reactor.