LN函数核截面隐式敏感性系数计算方法  

Calculation Method of LN Function Cross-section Implicit Sensitivity Coefficient

作　　者：胡馗 马续波[1] 张辰 刘莎 陈义学[1] HU Kui;MA Xubo;ZHANG Chen;LIU Sha;CHEN Yixue(School of Nuclear Science and Engineering,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学核科学与工程学院,北京102206

出　　处：《原子能科学技术》2024年第3期645-653,共9页Atomic Energy Science and Technology

基　　金：国家自然科学基金(11875128)。

摘　　要：许多新型反应堆由于能谱较硬,核数据引起的不确定度已成为反应堆物理设计主要不确定度的来源。之前针对快能谱反应堆的不确定度分析主要集中在显式敏感性系数计算及不确定度分析,对隐式效应的分析较少,很少对隐式效应的影响给出分析。本文在深入研究反应堆截面处理方法的基础上,提出了一种新的基于本底截面迭代方法的截面隐式敏感性效应分析方法,由于该截面隐式敏感性系数计算主要与LN函数相关,因此也称为LN函数隐式敏感性计算方法。并利用基准题对新方法计算的截面隐式效应进行了分析,证明了方法的正确性。针对提出的五核素快谱基准题,采用多群截面计算,在共振自屏效应强烈的能群,部分核截面敏感性系数隐式效应修正最大可达50%,针对少群截面,对于大多数反应道,考虑隐式效应后计算得到的k eff相对敏感性系数和不确定度计算精度均有明显提高,但有部分反应道可能是由于Bondarenko方法和窄共振近似本身问题,导致敏感性系数和不确定度精度改善不明显。For many new reactors,the uncertainty caused by nuclear data has become the main source of uncertainty in reactor physics design due to the higher uncertainty of measurement cross-section in the high energy region.Previously,uncertainty analysis for fast spectrum reactors mainly focused on explicit sensitivity coefficient calculation and uncertainty analysis,with less analysis of implicit effects and little analysis of the magnitude of their impact.The implicit effect of sensitivity coefficient is related to the processing method of resonance self-shielding cross-section,and due to the complexity of resonance self-shielding calculation,the implicit effect of sensitivity coefficient also becomes more complex.For example,for the problem of pressurized water reactors,implicit effects can be considered by solving the continuous energy spectrum slowing equation or changing the effective resonance integral table in the library.For thermal reactors,due to the need for neutron moderation to pass through the intermediate energy region with strong resonance self-shielding effect,the implicit sensitivity effect is relatively significant.When calculating the sensitivity coefficient,the implicit effect needs to be considered.For fast spectrum reactors(fast reactors),although the implicit effect is not very significant in theory,there has been no good method for calculating the implicit effect of sensitivity coefficients.The resonance self-shielding processing method based on background cross-section iteration is widely used in many reactor physics programs.A new implicit sensitivity effect analysis method based on the Bondarenko background cross-section iteration method was proposed in this study.The LN function was used to interpolate the background cross-section to represent the influence of cross-section disturbance on neutron spectra,and the influence was transmitted to the explicit sensitivity coefficient,thereby obtaining the sensitivity coefficient considering the implicit effect.Due to the fact that the implicit sensi

关 键 词：反应堆 隐式敏感性系数 敏感性系数计算 不确定度 

分 类 号：TL392[核科学技术—核技术及应用]