抄録
The AP1000 nuclear steam supply system (NSSS) is designed to accept full load rejection without initiating a reactor trip using the reactor power control system, pressurizer pressure and water level control systems, feedwater control system, steam dump control system and rapid power reduction (RPR) system. This paper presents the dynamic simulation and analysis of load rejection operations for the AP1000 NSSS. A real-time simulation platform is developed in Matlab/Simulink with implementation of a nodal core model, a three region nonequilibrium pressurizer model, a nonlinear steam generator model, a feedwater system model, a main steam system model, and the relevant control systems. Based on the simulation platform, two typical load rejection transients from full power (FP) are simulated, including the 50%FP load rejection without RPR and the large load rejection to 25%FP with RPR. The simulation results show that the NSSS control systems can successfully respond to load rejection transients without reactor trip or operation of the pressurizer or steam generator safety valves. Sustained stable operation can be obtained during the load rejection transients due to the proper control system responses.
