In view of the high leakage and strong heterogeneity of molten salt reactors,the whole-core transport calculation based on the method of characteristic(MOC)is suitable for the critical calculation of molten salt reactors.To balance computational efficiency and accuracy,the non-uniform spectra modification(nSM)method is proposed to generate the few-group cross sections for MOC whole-core calculations.This method is an embedded leakage modification method,which utilizes the leakage parameters obtained by the few-group MOC whole-core calculation for multi-group spectrum calculations,thereby online updating the few-group cross sections of the whole-core calculation.Compared with results from the continuous energy Monto Carlo code OpenMC for the MSRE two-dimensional whole-core benchmark problems,the keff errors calculated by nSM method are less than 0.25％and the maximum error of 2.6％in fission rate distributions occurs at the core can node with a relative fission rate of only 0.04,which are obviously better than those using the cross sections collapsed by the spectra calculated by assembly calculations.The results show that the approximate nSM method still has good accuracy,and could significantly improve the calculation efficiency.Therefore,nSM method could be a feasible method that provides few-group cross sections for the MOC whole-core calculation of molten salt reactors.
关键词
非均匀谱修正/熔盐堆/特征线方法(MOC)/全堆输运计算/少群截面加工
Key words
Non-uniform spectra modification/Molten salt reactors/MOC/Whole-core transport calculation/Generation of few-group cross sections
维普
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