In this paper, we present a formal Fourier analysis (FA) of Picard iteration for the coupled neutronics/thermal hydraulics (N/TH) problem and derive theoretical predictions for the spectral radius of Picard iteration for such coupled calculations as a function of the temperature difference between the fuel and coolant, temperature coefficients of cross sections (i.e., Doppler feedback), scattering ratio, and core height. An optimal underrelaxation factor is also derived based on the Fourier analysis.

翻译：本文对耦合中子学/热工水力学（N/TH）问题中的Picard迭代进行了形式化傅里叶分析（FA），推导了该耦合计算中Picard迭代谱半径的理论预测函数，该函数取决于燃料与冷却剂间的温差、截面温度系数（即多普勒反馈）、散射比以及堆芯高度。同时基于傅里叶分析，推导出了最优欠松弛因子。