基于蒙特卡罗方法的空间核反应堆在线截面处理与燃耗计算研究

Study on On-the-fly Cross-Section Treatment and Burnup Calculation of Space Nuclear Reactor Based on Monte Carlo Method

为解决蒙特卡罗(简称“蒙卡”)程序计算时的截面在线处理问题,针对可分辨共振能区,采用靶核运动抽样方法和改进高斯-厄米特方法计算不同燃料温度下的有效增殖系数(k_(eff)),将2种截面处理方法应用于千瓦级热管式空间核反应堆模型,并与使用精确温度截面库的k_(eff)计算结果进行对比。结果表明,对于不同温度下的k_(eff),2个方法的绝对误差都在±3倍的相对组合统计误差之内,靶核运动抽样方法和改进高斯-厄米特方法的计算时间分别增加了45%和9%。为解决空间堆中的蒙卡燃耗计算问题,将堆用蒙卡分析程序(RMC)的内耦合燃耗计算功能应用于兆瓦级热管式空间核反应堆模型和棱柱式高温气冷堆模型,并与典型蒙卡程序Serpent和MCNP进行对比。结果表明,每一个燃耗步下,k_(eff)的最大误差不超过0.2%和0.3%。2个研究初步验证了RMC对空间核反应堆在线截面处理和燃耗计算的正确性。

To solve the problem of on-the-fly cross-section treatment in the calculation of the Monte Carlo(MC)code,the target motion sampling method and the improved Gauss-Hermite method are used to calculate the effective multiplication factor(k_(eff))at different fuel temperatures for the resolvable resonance energy region.Two cross-section treatment methods are applied to the kilowatt-class heat pipe space nuclear reactor model and compared with the calculation results of k_(eff)using the accurate temperature cross-section library.The results show that for k eff at different temperatures,the absolute errors of the two methods are within±3 times the relative combined statistical error.The calculation time of the target motion sampling method and the improved Gauss-Hermite method increases by 45%and 9%,respectively.To solve the burnup calculation problem in space reactors,the internal coupling burnup calculation function of the Reactor Monte Carlo code(RMC)is applied to the megawatt-class heat pipe space nuclear reactor model and the prism-type high-temperature gas-cooled reactor model,and compared with typical MC code Serpent and MCNP.The results show that the maximum error of k_(eff)is less than 0.2%and 0.3%at each burnup step.Two studies preliminarily verify the correctness of RMC's on-the-fly cross-section treatment and burnup calculation of space nuclear reactors.