强非均匀Pin-by-pin历史效应处理技术研究  

History Effect Treatment in Strongly Heterogeneous Pin-by-pin Calculation

作　　者：王思成 曹良志[1] 李云召[1] 吴宏春[1] 杨杰伟 WANG Sicheng;CAO Liangzhi;LI Yunzhao;WU Hongchun;YANG Jiewei(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《原子能科学技术》2022年第1期39-45,共7页Atomic Energy Science and Technology

基　　金：国家自然科学基金(11775171)。

摘　　要：参数化过程是保障Pin-by-pin计算精度的重要环节,而传统组件主干-分支计算结合堆芯宏观燃耗计算的策略会导致参数化过程中出现历史效应。特别是对于以控制棒移动为代表的强非均匀Pin-by-pin问题,由于栅元之间的干涉,历史效应的影响更恶劣,微观燃耗修正技术与复合修正技术无法有效处理,有必要开发适用的历史效应处理技术。本文针对Pin-by-pin计算中的强非均匀运行历史,提出双向分支修正技术。双向分支修正技术在传统多主干计算时仅考虑名义主干向分支主干瞬时变化的基础上,针对控制棒移动等历史中栅元状态参数变化剧烈的特点,进一步考虑了分支主干向名义主干的瞬时变化。数值分析结果显示:对于由控制棒移动引入的强空间非均匀性历史,由单纯的微观燃耗修正技术和多主干复合修正技术得到的k_(eff)偏差均大于±1000 pcm;相比之下,双向分支修正技术的采用,能将k_(eff)的偏差保持在±300 pcm以内。数值结果证明,双向分支修正技术能有效处理Pin-by-pin计算中控制棒的移动历史。The parameterization process is an important part to ensure the accuracy of Pin-by-pin calculation.However,the traditional macro-depletion scheme which is based on the base-branch structure will lead to the history effect in the parameterization process.The existing methods to deal with the history effect include the following:1)The micro-depletion correction which is also based on the base-branch structure but requires the additional lattice output to track the nuclide density in core calculation;2)The hybrid correction method which is based on the multi-trunk structure.These methods are effective in dealing with homogeneous history problems such as boron concentration variations.However,due to the limitation of the method themselves,they cannot fully describe the instantaneous change process of the off-nominal base to the nominal base.Hence it is difficult for the existing methods to deal with the history when the pin-cell local state parameters are discrete changes,such as the control rod movement history.It might not be so serious in the assembly-homogenization-based two-step scheme.However,due to the refinement of the spatial mesh in the Pin-by-pin calculation,the interference between the pin-cells is stronger,which will worsen the history coming from the discrete changes of pin-cell local state parameters.Therefore,it is necessary to develop an acceptable history effect treatment method for such histories.In this paper,a bi-directional branch correction technique for the strongly heterogeneous operating histories was proposed for the Pin-by-pin calculation.In the traditional multi-base structure,only the depletion histories under the nominal base and the off-nominal base,and the instantaneous change from the nominal base to the off-nominal base can be considered.The bi-directional branch correction technique is a supplement to the traditional multi-base structure.The instantaneous change from off-nominal base to nominal base is further considered for the history of control bar movement,which shows the featu

关 键 词：压水堆 Pin-by-pin计算 历史效应 控制棒历史 NECP-Bamboo2.0 

分 类 号：TL32[核科学技术—核技术及应用]