Application of Nonlinear Iteration Method in Reactor Real-Time Simulation

It is difficult to satisfy both high precision and speed of the 3 D distribution calculation of reactor power, during the development of full scope simulator for nuclear power plants. A 3 D real-time simulation code is developed for reactor core based on the Nonlinear Iteration Method（NIM）. The coupled correction factor is calculated with long step time using Nodal Expansion Method（NEM） by its high accuracy. The flux and power are calculated in real-time using Coarse Mesh Finite Difference Method（CMFD） by its rapid speed. In contrast with the calculation of typical benchmark examples, the NIM simulation results showed that the calculation of reactor core using corrected coupling factor revised CMFD can not only keep the precision, but also can improve the calculation speed. NIM is a good 3 D real-time iteration strategy satisfied with the full scope simulator in nuclear power plants.