"Completion of Multiple Reciprocity Boundary Element Method for Liquid Criticality System Having Irregular Geometry"

“完成具有不规则几何形状的液体临界系统的多重互易边界元法”

• 批准号: 10558074
• 负责人: ITAGAKI Masafumi
• 金额: $ 3.14万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10558074/
• 关键词: reprocessing process; earthquake; liquid nuclear material; criticality safety; irregular geometry; multiple reciprocity method; boundary element data; preprocessor; 規則幾何形状

The aim of the research is to finalize the development of the criticality safety analyzing system based on the multiple reciprocity boundary element method (MRBEM). The main part of the system solves the three-dimensional, two-group neutron diffusion equation in order to analyze the nuclear criticality of liquid nuclear material systems in a reprocessing plant. In such analyses one often meets problems of irregular geometry, e.g., a listing or sloshing of liquid surface arising from an earthquake. The MRBEM is well suited for the analysis of such an irregular geometry since the method requires the discretization of the surface only rather than of the volume. Subdivision of a domain into mesh points or finite elements is not required since the critical eigenvalue itself is also calculated using only boundary integrals. In addition to this, the "preprocessor", which was introduced in the first year of the project to make boundary element data efficiently, has expanded the flexibility of analysis of complicated geometry. The MRBEM has been now reformulated to analyze the modified Helmholtz flux mode in a strong neutron absorber domain, as well as the ordinary Helmholtz one. Mathematical quantities that play an important role in the formulations are the zero-order and the higher order matrix-type fundamental solutions for the two-group neutron diffusion equation. Test calculations demonstrate the validity of the present reformulation and the usefulness when applied to the analysis of multi-domain criticality system The above research results were reported at the international conferences of boundary element research : BEM21 (1999) and BEM22 (2000). Further, results of analyses for actual sloshing experiments indicate the fact that the reactivity increases when a pan-cake shaped liquid suffers sloshing motion. As the product of the project, the whole computer system has been highly optimized and completed as a powerful tool for wide criticality analyses.(<300 words)

本研究的目的是完成基于多重互易边界元法（MRBEM）的临界安全分析系统的开发。该系统的主要部分求解三维二群中子扩散方程，以分析后处理厂中液态核材料系统的核临界性。在此类分析中，人们经常遇到不规则几何形状的问题，例如地震引起的液体表面的倾斜或晃动。 MRBEM 非常适合分析此类不规则几何形状，因为该方法仅需要表面而不是体积的离散化。不需要将域细分为网格点或有限元，因为临界特征值本身也仅使用边界积分来计算。除此之外，项目第一年引入的“预处理器”可以有效地生成边界元数据，扩展了复杂几何分析的灵活性。 MRBEM 现在已重新制定，可以分析强中子吸收域中的修改亥姆霍兹通量模式以及普通亥姆霍兹通量模式。在公式中起重要作用的数学量是两组中子扩散方程的零阶和高阶矩阵型基本解。测试计算证明了当前重新表述的有效性以及应用于多域临界系统分析时的有用性。上述研究结果已在国际边界元研究会议：BEM21（1999）和BEM22（2000）上报告。此外，实际晃动实验的分析结果表明，当薄饼状液体遭受晃动运动时，反应性增加。作为该项目的产物，整个计算机系统经过高度优化，完成了广泛关键性分析的有力工具。（<300字）

项目成果

M.Itagaki, S.Nisiyama, S.Tomioka, T.Enoto: "A Novel Boundary Element Method for Nonuniform Neutron Diffusion Problems"Journal of Nuclear Science and Technology. 36 [3]. 273-281 (1999)

M.Itagaki、S.Nisiyama、S.Tomioka、T.Enoto：“一种解决非均匀中子扩散问题的新型边界元方法”核科学与技术杂志。

S.Tomioka, S.Nisiyama, M.Itagaki, T.Enoto: "Internal field error reduction in boundary element analysis for Helmholtz equation"Engineering Analysis with Boundary Elements. 23 [3]. 211-222 (1999)

S.Tomioka、S.Nisiyama、M.Itagaki、T.Enoto：“亥姆霍兹方程边界元分析中的内部场误差减少”边界元工程分析。

M.Itagaki: "Advanced dual reciprocity method based on polynomial source and its application to eigenvalue problem for nonuniform media"Engineering Analysis with Boundary Elements. 24. 169-176 (2000)

M.Itagaki：“基于多项式源的高级对偶互易方法及其在非均匀介质特征值问题中的应用”边界元工程分析。

板垣正文,西山修輔,冨岡智,榎戸武揚: "A Novel Boundary Element Method for Nonuniform Neutron Diffusion Problems"Journal of Nuclear Science and Technology. 36[3]. 273-281 (1999)

Masafumi Itagaki、Shusuke Nishiyama、Satoshi Tomioka、Takeaki Enokido：“非均匀中子扩散问题的新颖边界元方法”核科学与技术杂志 36[3]。

板垣正文: "Advanced dual reciprocity method based on polynomial source and its application to eigenvalue problem for nonuniform media"Engineering Analysis with Boundary Elements. 24. 169-176 (2000)

Masafumi Itagaki：“基于多项式源的先进对偶互易方法及其在非均匀介质特征值问题中的应用”《边界元工程分析》24。169-176（2000）。