新型燃料组件计算软件SimFA燃耗计算策略研究与验证

Study and Verification of Burnup Calculation Strategy in Lattice Physics Code SimFA

如何在合理的时间步长下准确地模拟含钆(Gd)燃料的燃耗行为一直是组件计算程序开发工作中密切关注的问题。为了提高用于核电厂控制室全范围模拟机的少群截面参数的精确度,中核武汉核电运行技术股份有限公司(CNPO)开发了新型燃料组件计算软件Sim FA。本文对Sim FA的燃耗计算方法,特别是含Gd燃料的燃耗计算策略进行了介绍。与传统燃耗计算方法以及国际同类权威软件的计算结果比较显示,Sim FA采用的扩展的预估-校正方法(EPC)与带燃耗子步的线性反应率方法(LR)相结合的燃耗计算策略,在计算精度和计算速度方面表现出良好的综合性能,允许在不丢失计算精度的情况下用较大的时间步长进行燃耗计算,可以认为是一种适用于含Gd组件的燃耗计算策略。

Advanced analysis code on fuel assembly homogenization, Sim FA, has been developed by CNPO to improve the accuracy of few group cross section generation for the further use in the core code embedded in full-scope NPP control room simulators. In this paper, the burnup calculation strategy adopted in Sim FA, i.e. the Extended Predictor-Corrector Method incorporating the Linear Rate Method is presented, with the emphasis on Gadolinium-bearing assembly case. In comparison with the conventional burnup calculation methods, Sim FA demonstrates a better performance considering both the calculation efficiency and accuracy. The burnup calculation strategy implemented in Sim FA enables a fairly accurate burnup calculation with sufficiently large step size, and is therefore considered as a suitable way for the gadolinium-bearing assembly burnup calculation.