AP1000堆芯仿真计算建模与精度分析

Simulation Modeling and Accuracy Analysis of AP1000 Reactor Core

针对核电厂 AP1000 堆芯描述,建立由组件计算、截面拟合处理计算模型,并得到组件少群常数;采用两群三维,实时中子动力学仿真模型,选取 11 组衰变功率计算堆芯衰变功率的三维变化,同时为了准确计算反应堆的“中毒”变化,三维空间上考虑氙、钐以及先驱核碘、钜元素浓度的影响特性,建立针对 AP1000 堆芯实时仿真计算模型,并准确计算反应堆的“中毒”和氙振荡现象,为验证模型建立的正确性与堆芯实时仿真程序 SimCore 的精准性,对堆芯临界硼浓度、堆芯温度、控制棒价值进行计算,同时选取汽机停机不停堆、反应堆满功率跳堆运行,反应堆正常停堆运行及控制棒落棒、弹棒事故响应等不同测试工况,对结果进行验证及分析。结果表明:建立的三维堆芯实时仿真程序模具有较好的精准性,可以用于全范围模拟机堆芯计算,并广泛应用于核电厂堆芯物理仿真。

Aiming at AP1000 nuclear power plant reactor core description,a calculation model based on assembly calculation and cross section fitting is established,and a few group constants of assembly are obtained. Using two groups of three-dimensional,real-time neutron dynamics simulation models , 11 groups of decay power are selected to calculate the three-dimensional variation of core decay power. At the same time,in order to accurately calculate the “poisoning” changes of the reactor,the influence characteristics of xenon, samarium,precursor nuclear iodine and giant elements concentration are considered in three-dimensional space. To verify the correctness of the model and the accuracy of the real-time core simulation program SimCore,the critical boron concentration,core temperature and control rod value of AP1000 reactor core are calculated. At the same time,different test conditions,such as turbine shutdown without reactor shutdown,full power reactor trip, reactor normal shutdown operation, control rod drop, control rod ejection accident response and so on,are selected to verify and analyze the results. The results show that the three-dimensional core real-time simulation program has good accuracy and can be used for core calculation of full scope simulator,and is widely used in nuclear power plant core physical simulation.