超临界水冷堆冷却剂泵卡轴事故分析

Analysis on stuck shaft accident of coolant pump of supercritical water cooled reactor

以日本热谱超临界水冷堆SCLWR-H为研究对象,建立了相关热工物理计算模块。在反应堆冷却剂泵卡轴事故情况下,分析该堆在寿期初主冷却剂流量、燃料通道进口流量、内部燃料组件最高包层温度、堆芯压力、反应堆功率的变化情况以及寿期初、寿期中和寿期末3种情况下内部燃料组件最高包层温度的对比情况。得出的结论为:寿期初反应堆功率、堆芯压力呈下降趋势,内部燃料组件最高包层温度先快速升高后快速降低,最大升高值为132℃,但仍满足事故下安全设计准则;寿期中相对寿期末、寿期初相对寿期中及寿期末发生卡轴事故危害性更大。计算分析可为超临界水堆的安全特性定性分析提供基础性的参考。

Taking the heat spectrum supercritical water cooled reactor design model SCLWR-H proposed by Japanese as research object,the relevant thermal physical calculation modules were established.Under the assumptive stuck shaft accident of the reactor coolant pump,the variation trends of the main coolant flow rate,the flow rate in fuel channel inlet,the maximum cladding temperature of the internal fuel assembly,the core pressure and the reactor power in the beginning of the life-cycle of the reactor were analyzed,and the maximum values of the cladding temperature of the internal fuel assembly in the beginning,the medium-term and the end of the reactor life-cycle were compared.The obtained conclusion is as below,when the stuck shaft accident occurs during the beginning of the life-cycle of the reactor,the reactor power will reduce quickly,the core pressure will reduce gradually,the cladding temperature of the internal fuel assembly will rise quickly first,and then will reduce quickly,the maximum cladding temperature rise is 132℃,which is still meet the accident safety design criteria;the hazard of the stuck shaft accident occurred in beginning of life-cycle is largest,and the accident occurs in end of the life-cycle will has smallest hazard.The computational analysis in this paper can provide basic reference for qualitative analysis of safety characteristics of supercritical water cooled reactor.