核截面不确定度对西安脉冲堆keff计算结果的影响分析

Analysis on the Effect of Nuclear Cross Section Data Uncertainty to k_(eff) Calculation in Xi'an Pulsed Reactor

为了定量研究核数据的不确定度对西安脉冲堆k_(eff)计算结果的影响,利用国际上常用的敏感性和不确定度分析软件TSUNAMI-3D-K6及不同核数据库中的核截面数据,分析计算了西安脉冲堆两种堆芯布置下的k_(eff)及其不确定度。结果表明:核截面数据的不确定度会导致k_(eff)的不确定度在0.5%左右,核素235 U的裂变中子产额对k_(eff)不确定度的贡献最大,西安脉冲堆不同堆型下,由共振自屏计算得到的隐式敏感性系数差异较小,不同堆芯布置下计算得到的k_(eff)不确定度差异不大。

To investigate the uncertainty of nuclear data to keff calculation in Xi＇an Pulsed Reactor（XAPR）, a widely used TSUNAMI-3D-K6 code is used to study koff uncertainties with respect to two reactor core arrangements for XAPR. The results indicate that the accuracy of present nuclear cross-section data would bring an uncertainty about 0.5 % for keff while the number of neutron yield per fission of 235U contributes most to koff uncertainty. The implicit sensitivity coefficients caused by resonance shielding calculation have a little influence on the patterns of XAPR, and different arrangements in XAPR alter local sensitivi- ty coefficients, however it has no effect on the final uncertainty to koff.