六角形几何积分输运变分节块法及加速方法研究  

Study on hexagonal integral variational nodal method and acceleration method

作　　者：殷晗 张斌[2] 刘晓晶[1] 张滕飞 YIN Han;ZHANG Bin;LIU Xiaojing;ZHANG Tengfei(School of Nuclear Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Science and Technology on Reactor System Design Technology Laboratory,Nuclear Power Institute of China,Chengdu 610213,China)

机构地区：[1]上海交通大学核科学与工程学院,上海200240 [2]中国核动力研究设计院核反应堆系统设计技术重点实验室,成都610213

出　　处：《核技术》2020年第6期48-54,共7页Nuclear Techniques

基　　金：国家自然科学基金青年项目(No.11805122);国家自然科学基金优青项目(No.11922505)资助。

摘　　要：精确高效的中子学计算方法是快堆概念设计和方案优化的必备条件。本研究提出一种积分形式的变分节块法以求解六角形节块几何下的三维多群中子输运方程。该方法采用积分方法处理节块内部中子角通量密度,采用偶宇称球谐函数处理节块表面中子角通量密度,同时采用准反射边界条件方法减少节块表面的角度自由度数目,以节省计算成本。针对TAKEDA-4基准题的验证结果表明:相比于传统基于球谐函数离散的变分节块法,本方法在低阶角度近似下可将特征值计算偏差降低2~5倍;在高阶角度近似如P7近似下,加速算法能够实现33倍的加速比。研究建立的积分中子输运变分节块法可用于六角形组件几何快堆的高效、精确模拟。[Background]Accurate and efficient neutron calculation method is a prerequisite for fast reactor conceptual design and scheme optimization.[Purpose]The study aims to propose an integral form of variational nodal method to solve the three-dimensional multi-group neutron transport equation with hexagonal geometry.[Methods]The integral method was used to deal with the angular flux within hexagonal nodes while angular flux distributions on nodal interfaces are approximated by even-parity spherical harmonics.Besides,the quasi-reflected interface condition(QRIC)method was employed to reduce the number of interfacial angular terms to save computational costs.Finally,the TAKEDA-4 benchmark was taken for evaluation.[Results]The calculation results of TAKEDA-4 benchmark show that,compared with low angular order approximations,the integral method exhibits superior accuracy than the standard variational node method based on spherical harmonic discretization,and reduces the errors by 2~5 times in eigenvalue.In addition,the joint performance of the integral method and the QRIC method yields a remarkable computational time gain of 33.0 with the P7 angular approximation.[Conclusions]The integral variational node method presented in this paper realizes accurate and efficient simulation of fast reactor in hexagonal geometry.

关 键 词：变分节块法 六角形几何 积分方法 准反射边界条件 

分 类 号：TL99[核科学技术—核技术及应用]