Simulation Of Variable Load Control Characteristics Of Nuclear Power Secondary Loop System

The marine nuclear power secondary circuit system has many devices and complex structures,which requires it to have good stable dynamic performance during operation.Especially when the system is carrying out lifting and lowering loads,how to realize the dynamic process better and faster is an urgent problem to be solved.It is also the meaning and difficulty of simulation.This paper builds a nuclear power secondary loop system simulation model with GSE simulation software.The simulation model is used to verify the high and low load steady state.The results show that the model has higher accuracy.The simulation model is used to verify the high and low load steady state.The results show that the model has higher accuracy.The steam generator water level control and the secondary circuit load control are simulated by the lifting load dynamics.Among them,the water level control adopts single impulse PID control,three impulse feed-forward control and three impulse cascade-feed-forward control,and the power control adopts the average temperature of the primary circuit control and secondary circuit load control to simulate the lifting and lowering load of the system.The steam generator water level simulation results of the load reduction process show that the cascade-feedforward control and feedforward control have a slight increase in the false water level compared with the single impulse control,which is about 0.05%.However,the feedforward control is more than the single impulse control overshoot,which is reduced by 0.07%.And the cascade-feedforward control is reduced by 0.15% compared with the feedforward control overshoot;the steam generator water level stabilization time,the feedforward control is shortened by about 40 s compared with the single impulse control,and the cascade-feedforward is shortened compared to the feedforward control,which is About 37 s.When the load is increased,the cascade-feedforward control and feedforward control have a slight increase in the false water level compared with the single impulse control,which is about 0.03%.However,the feedforward control is reduced by 0.13% compared with the single impulse control overshoot.The feedforward is more than 0.09% less than the feedforward control overshoot.For the steam generator water level stabilization time,the feedforward control is shortened by about 37 s compared with the single impulse control,and the cascade-feedforward is shortened by about 28 s compared with the feedforward control.The simulation result of the second-circuit load control of the load-shedding process in the high power range shows that the average temperature of the primary coolant compares with the two-circuit main steam pressure constant method,the steam turbine over-regulation of the main turbine is reduced by 0.83%,and the stabilization time is shortened by about 291 s.The main turbine's power overshoot is reduced by 0.54 and the settling time is shortened by about 290 s.When the load is increased,for the steam flow rate of the main steam turbine inlet,the average temperature of the primary coolant compares with the two-circuit main steam pressure constant method,the settling time is shortened by about 59 s,and the main steam turbine power has no overshoot.The settling time is shortened by about 61 s.The simulation results of the second-circuit load control of the load-shedding process in the low-power range shows that the over-regulation of the main steam turbine inlet flow rate is 11.1% and the stabilization time is about 230 s.The over-regulation of the main steam turbine power is reduced compared with the main steam turbine inlet flow,which is 8.8%,and the stabilization time is shortened by about 30 s.When the load is increased,the overshoot of the main steam turbine inlet flow is 2.3%,and the settling time is about 220 s.Compared with the main steam turbine inlet flow,the overshoot is reduced by 2.2% and the settling time is shortened by about 37 s.