基于直接扰动法的keff敏感性及不确定度分析

Sensitivity and Uncertainty Analyses of keff Based on Direct Perturbation Method

本文在连续能量反应堆蒙特卡罗程序RMC中采用直接扰动法开发了敏感性分析功能,并使用该方法和一阶微扰理论方法,计算了Godiva临界基准题中keff对不同反应截面的敏感性系数,两种方法的计算结果基本吻合,证明了本文在RMC中开发的基于直接扰动法的敏感性分析功能的正确性。同时,本文还基于微扰理论方法和随机抽样方法,利用SCALE6.2程序包中的56群和252群协方差数据,计算了Godiva临界基准题中不同反应截面下keff的不确定度。结果表明,协方差数据的能群结构划分对keff的不确定度无显著影响。

In this paper,the direct perturbation method is used to develop the sensitivity analysis capability in the continuous-energy reactor Monte Carlo(RMC)codes.The sensitivity coefficients of keff in the Godiva critical benchmark problem to different reaction cross sections are calculated by using this method and the first-order perturbation theory method,respectively.The results calculated by the two methods agree well,which prove the correctness of the sensitivity analysis capability based on the direct perturbation method developed in RMC.At the same time,based on the perturbation theory and random sampling method,the uncertainty of keff induced by different cross sections of the Godiva critical benchmark is calculated by using 56 groups and 252 groups covariance data in SCALE6.2 package.The results show that the energy group structure of covariance data has no significant effect on the uncertainty of keff.