Coarse mesh rebalance (CMR) method is formulated for the acceleration of fission source iteration (FSI) in the multigroup transport theory analysis of subcritical source-driven systems. The within-group equations are solved by diamond-differenced S_N method and CMR has been employed also for the acceleration of scattering source iterations. By numerical experiments, carried out in spherical geometry, stability and performance characteristics of the proposed acceleration are determined and assessed. Systems containing a central nonmultiplying source region and an outer multiplying blanket region are considered. CMR is stable provided that the number of coarse mesh regions in the blanket is in a stability interval between a minimum and a maximum value, irrespective of the fine mesh used in S_N calculations. Maximum acceleration is obtained for an optimum number of blanket coarse mesh regions which is also independent of the fine mesh. Both the width of the stability interval and the optimum speed-up ratio (execution time ratio of the unaccelerated run to the accelerated one) increases as the system becomes optically thicker. If we let the system approach criticality by increasing the blanket size, the number of FSIs increases dramatically if no acceleration is employed. For such slightly subcritical systems, very high speed-up ratios are obtained with CMR acceleration whose performance is independent of the criticality level.

在亚临界源驱动系统的多组输运理论分析中，为加速裂变源迭代（FSI）制定了粗网格重新平衡（CMR）方法。组内方程通过菱差S _N方法求解，并且CMR也已用于加速散射源迭代。通过在球形几何形状中进行的数值实验，确定并评估了拟议加速度的稳定性和性能特征。考虑包含中心非乘法源区域和外部乘法覆盖区域的系统。只要橡皮布中的粗网格区域的数量在最小值和最大值之间的稳定区间内，则CMR是稳定的，而与在网格中使用的细网格无关S _N计算。对于最佳数量的橡皮布粗网格区域，可以获得最大加速度，而该最佳数量也与细网格无关。稳定间隔的宽度和最佳加速比（未加速运行与加速运行的执行时间比）都随着系统的光学厚度增加而增加。如果我们通过增加覆盖层大小使系统接近临界状态，那么如果不使用加速，FSI的数量将急剧增加。对于这样的次临界系统，通过CMR加速可以获得非常高的加速比，而其性能与临界水平无关。