基于连续能量蒙特卡罗的快中子反应堆均匀化截面计算方法研究  

Generating Multi-group Homogenized Cross-sections Using Continuous-energy Monte Carlo Method for Fast Reactor Analysis

作　　者：郭辉 沈宇阳 吴逸炜 陈萃岚 宋去非 顾汉洋[1] GUO Hui;SHEN Yuyang;WU Yiwei;CHEN Cuilan;SONG Qufei;GU Hanyang(School of Nuclear Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学核科学与工程学院,上海200240

出　　处：《原子能科学技术》2024年第3期593-603,共11页Atomic Energy Science and Technology

基　　金：国家自然科学基金(12105170,12135008);核反应堆系统设计技术重点实验室基金。

摘　　要：快堆确定论两步法通常由组件均匀化截面计算和堆芯扩散/输运计算共同组成,已广泛应用于快堆工程设计与分析领域。基于连续能量精细几何的蒙特卡罗均匀化截面计算方法可为先进快堆提供高精度均匀化群常数。本文简要综述了蒙特卡罗生成的均匀化截面与堆芯扩散/输运计算结合的发展现状与技术趋势。介绍了蒙特卡罗体积通量均匀化方法和超级均匀化等效修正方法,提出了蒙特卡罗通量矩均匀化方法。以MET-1000金属燃料快堆数值对标为例,针对堆芯扩散计算,对控制棒使用超级均匀化等效修正方法,将堆芯扩散计算的控制棒价值高估从13.5%减小到0.35%,并提高了功率分布预测精度;针对堆芯输运计算,定量解析了误差原因,提出了蒙特卡罗通量矩均匀化方法,可减小MET-1000堆芯输运计算的反应性误差698 pcm。本文中适用于快堆扩散及堆芯输运计算的蒙特卡罗均匀化截面生成方法针对先进非均匀布置快堆、小型快堆等新型堆芯,与不同堆芯求解器的结合有待进一步发展与验证。同时,蒙特卡罗生成快堆均匀化截面还有许多问题需要深入研究,如不连续因子修正、基模修正、历史效应处理方法等。The deterministic two-step method for the fast reactor neutronics calculation,composed of cross-section homogenization and diffusion or transport core calculations,was widely applied in the fast reactor engineering design and analysis field.The homogenized cross-section calculation method based on Monte Carlo with continuous-energy and fine geometry can provide high-precision cross-sections for advanced fast reactors.The current development status and trends of coupling Monte Carlo-generated homogenized cross-sections with diffusion and transport core calculations were briefly reviewed in this paper.The methods discussed include the Monte Carlo flux-volume homogenization method,the superhomogenization equivalence technique(SPH),and the Monte Carlo flux-moment homogenization method(MHT).The MET-1000 metal fuel fast reactor is used as a benchmark.The SPH equivalent techniques are widely used to preserve the reaction rates of a reference heterogeneous model and a homogenous model.In this paper,the SPH was applied to the control rods’cross-section address to improve the diffusion core calculations.This equivalence technique reduces the overestimation of the control rod worth using the diffusion core solver from 13.5%to 0.35%and improves power distribution prediction accuracy.With SPH correction,the MC/diffusion in this work exhibits about<±4%error as the insertion of control rods in power distribution.For the transport core calculations,the reasons for core reactivity overestimation were quantitatively analyzed,and the MHT method was developed.The basic principle of the MHT homogenization method is to incorporate the anisotropy of the total cross-section concerning the incident angle into the scattering matrix.This allows for the consideration of cross-section anisotropy while maintaining the generality of the generated total cross-section within the core transport solver.The MHT reduces the error of the transport core solving of MET-1000 by 698 pcm.The factors that cause the residual bias were discussed,but there

关 键 词：快堆 蒙特卡罗 确定论两步法 均匀化 多群截面 

分 类 号：TL371[核科学技术—核技术及应用]