一种通过边界注量率耦合的MOC和S<sub>N</sub>二维耦合中子输运方法

张思凡; 袁媛; 刘宙宇; 周欣宇; 曹良志

doi:10.13832/j.jnpe.2022.02.0009

一种通过边界注量率耦合的MOC和S_N二维耦合中子输运方法

doi: 10.13832/j.jnpe.2022.02.0009

1.
西安交通大学核科学与技术学院，西安，710049
2.
中国核电工程有限公司，北京，100840

基金项目: 国家重点研发计划（2017YFE0302200）；国家自然科学基金（11735011）

详细信息

作者简介:
张思凡（1997—），男，硕士研究生，现主要从事反应堆物理研究工作，E-mail: 872652654@qq.com

通讯作者:
刘宙宇，E-mail: zhouyuliu@mail.xjtu.edu.cn

中图分类号: TL323
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- 被引次数: 0
出版历程
- 收稿日期: 2021-01-11
- 修回日期: 2021-07-29
- 刊出日期: 2022-04-02

A Two-dimensional Coupled Neutron Transport Method for MOC and S_N via Boundary Fluence Rate Coupling

1.
School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an, 710049, China
2.
China Nuclear Power Engineering Co., Ltd., Beijing, 100840, China

摘要

摘要: 当使用特征线方法（MOC）计算堆外探测器或某些特殊的重水慢化轻水冷却的实验堆时，因其活性区外部结构材料或慢化剂区域过大，密集的特征线会导致计算资源大量浪费。为解决这一问题，提出了一种新的基于MOC和离散纵标（S_N）节块法的耦合输运方法，并在数值反应堆物理计算程序NECP-X中实现。该方法将计算区域划分为MOC域（包括活性区等复杂结构区域）和S_N域（包括慢化剂和反射层等简单结构区域），然后对2个区域的网格进行混合扫描，通过区域交界面的角注量率进行耦合；同时提出了一些可行的方法来减缓耦合边界角注量率带来的误差。最后通过二维C5G7基准题和全堆芯问题的测试来验证耦合方法的计算效果，数值结果表明该方法具有良好的计算效率和精度。
- 特征线方法（MOC） /
- 离散纵标（S_N）节块法 /
- 混合扫描 /
- NECP-X
Abstract: When the method of characteristics (MOC) is used to calculate the out-of-pile detector or some special heavy water moderated light water cooled experimental reactor, the dense characteristics will lead to a large waste of computing resources because the external structural material or moderator area of its active region is too large. To solve this problem, a new coupled transport method based on MOC and discrete ordinate (S_N) nodal method is proposed and implemented in the numerical reactor physics calculation program NECP-X. In this method, the calculation region is divided into MOC domain (including complex structure regions such as active region) and S_N domain (including simple structure regions such as moderator and reflector), and then the grids of the two regions are subject to hybrid sweeping and coupled through the angular fluence rate of the region interface; At the same time, some feasible methods are proposed to reduce the error caused by the fluence rate of the coupling boundary angle. Finally, the calculation effect of the coupling method is verified by the test of two-dimensional C5G7 benchmark task and whole core problem. The numerical results show that the coupling method achieves superior efficiency and accuracy.
- Method of characteristics (MOC) /
- Discrete ordinates (S_N) nodal method /
- Hybrid sweeping scheme /
- NECP-X

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图 1 混合扫描流程

Figure 1. Flowchart of Hybrid Sweeping

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图 2 耦合方法的二维C5G7基准题建模

Figure 2. 2D C5G7 Benchmark Task Modeling in Coupling Method　　　　　

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图 3 二维C5G7问题的4种建模方案

Figure 3. Four Modeling Schemes of 2D C5G7 Task

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图 4 4种方案MOC域右侧边界出射注量率形状

Figure 4. The Outgoing Fluence Rate Shape of the Right Boundary of the MOC Domain of the Four Schemes

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图 5 4种方案活性区右边界角注量率形状

Figure 5. The Fluence Rate Shape of the Right Boundary Angle of the Active Region of the Four Schemes

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图 6 D₂O堆芯功率及其偏差

白色背景数字表示归一化的绝对功率；有颜色背景数字表示功率偏差，单位为%

Figure 6. D₂O Core Power and Its Deviation

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表 1 二维C5G7问题的4种建模方案详细信息

Table 1. Details of Four Modeling Schemes for 2D C5G7 Task　　　　　　

方案	计算域	x方向尺寸/cm	y方向尺寸/cm
0	MOC	42.84	42.84
1	MOC	42.84+1.26	42.84+1.26
2	MOC	42.84+1.26×2	42.84+1.26×2
3	MOC	42.84+1.26×3	42.84+1.26×3

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表 2 二维C5G7四种建模方案特征值和功率计算结果

Table 2. Eigenvalue and Power Calculation Results of Four Modeling Schemes for 2D G5C7

方案	k_eff	k_eff偏差/ pcm	组件功率最大偏差/%	棒功率最大偏差/%
参考值	1.18679	—	—	—
方案0	1.18676	−3	0.07	11.23
方案1	1.18670	−9	0.02	4.68
方案2	1.18671	−8	0.01	1.54
方案3	1.18672	−7	0.01	0.76
“—”表示无此项，下同

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表 3 二维C5G7四种建模方案计算时间

Table 3. Computation Time of Four Modeling Schemes for 2D G5C7

方法	输运时间/s	MOC 时间/s (占比/%)	S_N时间/s (占比/%)	迭代次数
传统MOC	2880.66	2880.66	—	631
方案0	1139.51	1052.28 (92.34)	87.23 (7.66)	631
方案1	1296.77	1198.88 (92.45)	97.89 (7.55)	631
方案2	1361.48	1263.66 (92.82)	97.82 (7.18)	631
方案3	1431.94	1335.59 (93.27)	96.35 (6.73)	631

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表 4 重水慢化堆芯特征值和功率计算结果

Table 4. Eigenvalue and Power Calculation Results of Heavy Water Moderated Reactor Core

计算结果	参考解	耦合方法（偏差）
k_eff	1.27647	1.27602 (−45 pcm)
组件功率最大偏差/%	—	−0.05
棒功率最大偏差/%	—	1.15

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表 5 重水慢化堆芯计算时间

Table 5. Computation Time for Heavy Water Moderated Reactor Core

方法	扫描时间/h	MOC时间 /h (占比/%)	S_N时间 /h (占比/%)	迭代次数	平均扫描时间/s
传统MOC	83.71	83.71	—	2921	103.18
耦合方法	10.70	7.35 (68.69)	3.35 (31.31)	3668	10.5

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