Modeling And Simulation Of VVER-440 Reactor Core By APROS

In recent years,nuclear power as a new type of clean energy and economic new energy has become an important way to replace conventional energy at this stage.While supporting the development of nuclear power,the state also pays more attention to the safety of nuclear power.From the point of view of reactor dynamics,the transient characteristics of the neutron flux density deviating from the critical state are very important to the control and safe operation of the reactor.The real-time simulation of the neutron flux density involves the start stop reactor,the power regulation,the rupture of the coolant pipe,the control rod from the reactor during the operation of the reactor.It is of great significance to monitor and analyze the transient process in the core and other transient processes.Moreover,the complexity of neutron dynamics and thermo hydro mechanical coupling in reactor core is difficult at present.Therefore,based on the safety analysis,based on the reasonable simplification of the core of the VVER-440 reactor,the APROS Nuclear simulation software is used to establish the neutron dynamic model and the thermal hydraulic model for the core of the VVER-440 reactor,in order to accurately describe the feedback effect between the two models.The coefficient of reactivity is reasonably coupled to the two.Finally,on the basis of the core model,the control rod control system corresponding to it is established,and the model is used to simulate the different working conditions of the reactor steady state,the reactor and the shutdown.Finally,the simulation results are analyzed and studied.The simulation contents mainly include the following three aspects.?1?the transient characteristics of fast neutron and thermal neutron flux density under different working conditions are simulated.The simulation results are in good agreement with the actual situation of neutron in PWR Core.?2?by changing the effective proliferation factor keff of the reactor,the core power level is changed,and the response of the control rod control system is monitored.The control rod control system can respond quickly to different conditions.?3?considering the control of reactor core system's reactivity,we analyze and analyze the poisoning situation in the core of reactor under two working conditions,namely,reactor start-up and shutdown.The calculation results in core model about¹³⁵Xe,¹³⁵ I,¹4949 Sm and ₁₄₉49 Pm are consistent with the actual situation of PWR Core.Based on the APROS Nuclear software,the core simulation model of the VVER-440 reactor and the automatic control system of the control rod assembly are set up to verify the reliability and accuracy of the APROS Nuclear software for the simulation results of the core.It provides an important reference for the power transient monitoring and the design of the control system in the core of the nuclear reactor.We will lay a solid foundation for developing the safe operation of nuclear reactors.