熔盐堆低功率工况下反应性引入事故初始条件敏感性探讨  

Study on sensitivity of initial conditions of reactivity initiated accident under low power conditions of molten salt reactor

作　　者：焦小伟[1] 王凯[1] 王超群 杨群[1] 何兆忠[1] JIAO Xiaowei;WANG Kai;WANG Chaoqun;YANG Qun;HE Zhaozhong(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800

出　　处：《核技术》2021年第6期82-88,共7页Nuclear Techniques

基　　金：中国科学院青年创新促进会项目(No.Y929022031)资助。

摘　　要：熔盐堆低功率工况反应性引入事故中,不同的反应性引入速率将触发不同的停堆信号。同时反应堆初始功率和反应性温度系数等初始条件影响事故的进程,引起事故后果的差异。本文选取了7个反应性引入速率工况、25个初始功率水平和反应性温度系数的参数组合初始工况,分别讨论了这三个参数对事故后果的影响。分析结果表明:熔盐堆低功率工况反应性引入事故的后果对反应性引入速率的变化较敏感,在其他初始条件一定的情况下,存在特定的反应性引入速率会导致最不利的事故后果;事故后果对反应堆初始功率和反应性温度系数的变化不敏感,由初始功率和反应性温度系数差异造成的事故后果差异较小。[Background]In the reactivity initiated accidents under low power operating conditions of molten salt reactor(MSR),different reactivity insertion rates will trigger different emergency shutdown signals.At the same time,the initial conditions such as the initial reactor power and the temperature coefficients of reactivity affect the accident process and cause differences in accident consequences.[Purpose]The study aims to conduct a sensitivity analysis of the impact of the reactivity insertion rate,the initial reactor power,and the reactivity temperature coefficient on transient consequences.[Methods]First of all,7 reactivity insertion rate conditions were selected and simulated through RELAP5-TMSR.Then,25 combinations of the initial reactor power and the temperature coefficients of reactivity were assumed as initial conditions.Finally,the effects of these three parameters on the consequences of the accident were discussed separately by using local sensitivity analysis method.[Results]The insertion rate that causes a concurrent trigger of the high outlet temperature and the high-power shutdown signal leads to the most unfavorable consequence.The difference between the peak temperatures of the fuel salt and structural materials and their respective initial values under the worst reactivity insertion rate condition is negatively correlated with initial power.However,the temperature difference of each parameter caused by different initial power does not exceed 3℃.The difference between the peak temperatures decrease first and then increases with the increase of the temperature coefficients of reactivity,but the maximum difference does not exceed 0.5℃.[Conclusions]Under low power operating conditions of MSR,the consequences of reactivity introduced events are highly sensitive to the reactivity insertion rate and low sensitivity to the initial power and temperature coefficients of reactivity.

关 键 词：熔盐堆 低功率 反应性引入事故 敏感性 

分 类 号：TL36[核科学技术—核技术及应用]