小破口失水事故最佳估算的不确定性和敏感性分析

本文采用RELAP5最佳估算程序对我国建造的先进热工水力试验（ACME）台架进行了小破口失水事故模拟，并开展了不确定性定量化评估，包括输入不确定性参数的选取、Wilks非参数统计方法的应用以及基于SNAP平台的不确定性传播计算，最后对计算结果进行了不确定性和敏感性分析。计算得到关键参数的95/95不确定性包络带，其中最小堆芯液位的下限仍保持在堆芯活性区以上，表明堆芯有95%的置信度未发生裸露。通过敏感性分析判别出对最小堆芯液位影响较大的输入不确定性参数。

Uncertainty and Sensitivity Analysis of SBLOCA Best-estimate Calculation

The RELAP5 best-estimate code was used to perform small break loss of coolant accident (SBLOCA)for the ACME (advanced core-cooling mechanism experi-ment)facility built in China.Thereafter,uncertainty quantification evaluation was performed,including the selection of input uncertain parameters,the application of Wilks nonparametric statistics and the calculation of uncertainty propagation based on SNAP interface.Furthermore,the results of uncertainty and sensitivity analysis were discussed.The 95/95 uncertainty bands of key output parameters were obtained,and the lower band of minimum core level is maintained still above the top of the active core section,thus the core uncover does not occur with 95% confidence.Important uncer-tainty contributors for the minimum core level are identified through sensitivity analysis.