核融合施設へのPHITSの適用と改良に向けた調査(委託研究)

Investigation for application and improvement of the PHITS code to nuclear fusion facilities (Contract research)

助川 篤彦; 仁井田 浩二*

Sukegawa, Atsuhiko; Niita, Koji*

核融合施設へのPHITSの適用と改良に向けて、計算精度の検証及び計算効率の技術的な課題の抽出を行った。単純体系、超伝導トカマク装置を模した複雑体系、及び、核融合用加速器を含む実験体系を用いた計算のベンチマークから、同じ評価済核データライブラリー、同じ幾何形状モデル、同じ線源を用いる限り、PHITSで計算される中性子、光子のフラックスは、MCNPの結果と統計誤差範囲で一致することがわかった。これに加えて、分散(統計誤差)を低減するための方法としてWeight Windowを用いた場合も、PHITSとMCNPで計算される中性子、光子のフラックスは統計誤差範囲で一致することがわかった。

The accuracy and efficiency of the PHITS code has been investigated towards the application to the fusion facilities by making comparison between PHITS and MCNP calculation for a simplified cylindrical model, for a 3D detailed model of tokamak fusion device, and for experimental assembly models of accelerator for fusion facilities. It was clarified that the results of neutron and photon spectrum obtained by the PHITS code agree with those of MCNP within statistical errors as far as they use the same cross section library, the same model and the same neutron source for the calculation. Moreover, the results of both codes are consistent each other within statistical errors for the case with the same weight window method as a variance reduction technique.