Improvement of Tone's method with two-term rational approximation

二項有理近似を用いた東捻の方法の改良

山本 章夫*; 遠藤 知弘*; 千葉 豪

Yamamoto, Akio*; Endo, Tomohiro*; Chiba, Go

等価原理に基づく共鳴計算手法である東捻の方法の改良を提案する。計算精度を向上させるため二項有理近似を中性子束の表現に導入した。さらに、東捻の方法の理論的な解釈を行い、導入される近似や衝突確率計算に用いる多群断面積の適切な選択の方法について議論した。また、改良した方法の妥当性を不規則配列格子の計算により確認した。

An improvement of Tone's method, which is a resonance calculation method based on the equivalence theory, is proposed. In order to increase calculation accuracy the two-term rational approximation is incorporated for the representation of neutron flux. Furthermore, some theoretical aspects of Tone's method, i.e., its inherent approximation and choice of adequate multi-group cross section for collision probability estimation, are also discussed. The validity of the improved Tone method is confirmed through a verification calculation in a irregular lattice geometry, which represents part of a LWR fuel assembly. The calculation result clarifies the validity of the present method.