一体化压水堆强迫循环转自然循环过渡过程特性分析

针对一体化压水堆核动力装置，以核动力装置瞬态最佳估算程序RELAP5/MOD3为基础，采用两群三维时空中子动力学模型替代点堆模型，并建立三维空间内中子物理与热工水力的耦合模型,研制相应的计算程序。对一体化核动力装置强迫循环向自然循环转换过程进行仿真模拟。在过渡过程中，一体化压水堆核动力装置反应堆功率变化幅度较大，冷却剂流量的变化对一回路温度影响较大。

Research on Transition Process From Forced Circulation to Natural Circulation of Integrated Pressurized Water Reactor

The analysis code for an integrated pressurized water reactor was developed on the basis of best-estimate transient analysis code RELAP5/MOD3 for nuclear power plan. The point reactor kinetics model in the original code was replaced by the two-group, 3-D spatial and temporal neutron kinetic model. The coupling model for three dimensional physics and thermal hydraulic was established. The transition process from forced circulation (FC) to natural circulation (NC) was simulated with this code. During the transition from FC to NC, the variation of reactor power is significant, while the coolant temperature is greatly affected by the coolant flow rate.