Simulation modeling and accuracy analysis of AP1000 reactor core

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. (authors)