The errors in pin-homogenized multigroup calculation (PHMGC) from various sources are thoroughly analyzed to find the optimal neutronics solution method. The dependence of the errors due to the use of pin-homogenized multigroup cross sections on the energy groups are investigated first to clarify the need for proper equivalence factor and more groups in pinwise calculation. Various transport approximations including the simplified P_N (SP_N) and the discrete ordinate method (S_N) are then examined with different degrees of spatial discretization. It is demonstrated that the diffusion calculations involve significant error cancellation which would result in seemingly good results. It turns out that SP₅ is not any better than SP₃ and S_N yields intolerable errors due to the inconsistency of single assembly based SPH factors especially noted in the fast energy range. Through the analyses, the source expansion nodal method solver of the SP₃ equations is determined as the optimal solver for PHMGCs.

对来自各种来源的针均质化多群计算 (PHMGC) 中的误差进行了彻底分析，以找到最佳中子学求解方法。首先研究由于使用 pin 均质化多组横截面而导致的误差对能量组的依赖性，以阐明在 pinwise 计算中需要适当的等效因子和更多组。包括简化的 P _N (SP _N ) 和离散纵坐标法 (S _N )在内的各种传输近似值随后会通过不同程度的空间离散化进行检查。结果表明，扩散计算涉及显着的误差消除，这将导致看似良好的结果。事实证明，SP ₅并不比 SP 好由于基于单个组件的 SPH 因子的不一致，尤其是在快速能量范围内，因此₃和 S _N产生了无法容忍的错误。通过分析，确定了SP ₃方程的源扩展节点法求解器作为PHMGCs的最优求解器。