船用压水堆中破口失水事故不确定性及敏感性分析

Uncertainty and Sensitivity Analysis of MB-LOCA in Shipboard Reactor

论文基于输入参数不确定性传播的GRS评价方法,利用Matlab软件开发完整有效的中破口失水事故(MB-LOCA)不确定性分析程序,批量运行RELAP5/MOD3.2最佳估算程序模拟某船用压水堆MB-LOCA的瞬态进程。通过对多组燃料包壳温度的运算结果进行不确定性量化计算得到包壳峰值温度(PCT)的最高值与变化区间,采用Spearman相关性系数对结果进行敏感性分析,筛选出对目标参数具有显著影响的不确定性输入参数,提出事故缓解优化方案。研究表明:PCT的上限仍保持在1477K以下,堆芯有95%的置信度未发生损坏,反应堆运行功率对PCT有显著的正相关影响,优化策略能够有效增强反应堆的事故缓解能力,有利于事故的科学处置。

Based on the GRS evaluation method of input parameter uncertainty propagation,a complete and effective uncer⁃tainty analysis program for mid-break loss of coolant accident(MB-LOCA)is developed by using Matlab software,and ran the RE⁃LAP5/MOD3.2 best estimation program in batches to simulate the transient process of MB-LOCA of a marine pressurized water reac⁃tor.The highest value and variation interval of PCT are obtained by quantifying the uncertainty of the temperature of multiple sets of fuel cladding,and the sensitivity analysis of the results is carried out by using the Spearman correlation coefficient,and the uncer⁃tainty input parameters with significant influence on the target parameters are screened out,and an accident mitigation optimization scheme is proposed.The results show that the upper limit of the PCT is still maintained below 1477K,the core has 95%confidence level without damage,the reactor power has a significant positive correlation effect on the PCT,and the optimization strategy can ef⁃fectively enhance the accident mitigation ability of the reactor,which is conducive to the scientific disposal of the accident.