AP1000堆芯物理计算中核数据对k_(eff)的敏感性与不确定性分析

Sensitivity and Uncertainty Analysis of Nuclear Data to k_(eff) in AP1000 Core Physics Calculation

核数据作为反应堆计算的输入参数,其不确定性对堆芯物理计算至关重要。以第3代先进压水堆AP1000首循环零功率堆芯为研究对象,采用SCALE6.1程序建立堆芯物理模型,分别计算了反应堆冷态和热态工况下,5种典型硼浓度的堆芯有效增殖因子k_(eff),并与AP1000设计文件基准值进行比对,误差在50 pcm以内,验证了模型准确性。随后开展核数据对k_(eff)的敏感性和不确定性分析,结果表明,低能区中^(235)U的平均裂变中子产额、^(10)B的(n,α)反应截面、共振区中^(1)H的弹性散射截面、快中子区中^(238)U的裂变截面具有较大的敏感性与不确定性,在反应堆物理计算工程中应重点关注。

Nuclear data is used as the input parameter of reactor calculation,and its uncertainty is very important to the calculation of core physics.This paper takes first-cycle zero-power reactor core of the third-generation advanced pressurized water reactor AP1000 as the research object,and uses the SCALE6.1 program to establish the core physical model.Under the cold and hot conditions,the core effective multiplication factor k_(eff) of five typical boron concentrations was calculated separately.The calculation result is compared with the benchmark value of AP1000 design file,and the error is within 50 pcm,which verifies the accuracy of the model.Subsequently,the sensitivity and uncertainty analysis of nuclear data to k_(eff) was carried out.The results showed that the average fission neutron yield of ^(235)U and the(n,α)reaction cross section of ^(10)B in the low energy region,the elastic scattering cross section of 1H in the resonance energy region,and the fission cross section of ^(238)U in fast neutron region has greater sensitivity and uncertainty.They should be focused on in the future reactor physical calculation engineering.