| The solid-state molten salt reactor,also known as the Fluoride Salt-Cooled High Temperature Reactor(FHR),is distinguished from the liquid molten salt reactor design of the fuel salt flowing through the primary loop,which uses the spherical fuel element prepared by the coated particles,and the molten salt only takes heat as the coolant.The solid-state molten salt reactor has high economic and safety due to the high heat capacity of the molten salt and the inclusion of the fuel-coated particles on the radioactive substance.However,the pile type is still in the stage of physical research and design,and there is no real pile built,and there is no historical operation experience.Therefore,it is of great significance to develop the feasible operation mode and control logic for the development of this type of reactor.This paper will carry out the physical research and put forward the theory and feasible operation and control scheme in combination with the characteristics and operating characteristics of the reactor.In the process of real-time control of reactor power,a variety of reactor power control modes have been developed.In which,the basic load operation mode or the load following operation mode is generally adopted in the nuclear power plant.The basic load operation mode is adopted by the earlier reactor due to its relatively simple control logic.The load following operation mode can adjust the power of the reactor accordingly according to the change of the load,and is adopted by an increasing number of reactors due to the flexibility of its power control.By adopting the load-following operation mode,the fuel life period can be prolonged,and the operation efficiency of the unit is further improved;and meanwhile,the purpose of coordinating the capacity of the unit and the demand of the power grid is also achieved.In the course of reactor load following operation,the typical load change transient is a necessary condition to measure whether the power control system meets the design requirements.For example,the "12-3-6-3" scheme,the 5% FP/ min rate linear lift power,and the step 10% FP load change,etc.The corresponding design requirements can only be met if these conditions are met without causing reactor shutdown or steam emission.As a solid-state molten salt reactor,its application target has no significant difference with the conventional pressurized water reactor,and therefore,the typical load change transient adopts the same scheme as that of the conventional pressurized water reactor.For the research of solid-state molten salt reactor,this paper focuses on the following four points:(1)The system modeling of the solid-state molten salt reactor is carried out by using RELAP5 as the system analysis program.The operating status of the reactor is analyzed under typical load transients.And further analyzes the influence of the control system on the operation state of the reactor in the case of the error of the measuring instrument.Thereby confirming the safety characteristics of the reactor.(2)The data interaction function of RELAP5 is developed.In order to further study the control system of molten salt reactor and make it possible to transmit data with MATLAB,EPICS,or Windows system,the function of RELAP5 is extended.The extended RELAP5 has the function of outputing data to other external programs and can read the required information to provide tool support for future research.(3)The graphical user interface is established.The system control interface is built with the GUI module of MATLAB.So that the thermal power,the control and the protection system are presented to the user in a visual and visual way.And the interactive interface is preliminarily provided with the function of the simulation machine.The transient problem under the change of the core power distribution is studied.The core power distribution was changed due to control rod movement.With the data interaction function of the modified RELAP5 and MATLAB,the power distribution information of the control rod in different positions is provided by the MATLAB,and several operation transients are simulated by using the RELAP5.So as to study whether the change of the core power distribution has an effect on the simulation of the reactor.The fuzzy PID control function of the control rod is set up through the Simulink and the fuzzy toolbox of MATLAB,and the transient simulation of the complex control logic in the solid-state fused-salt stack system is carried out by using the modified RELAP5 and the data interaction function of the MATLAB,and the typical case of the load following is analyzed.(4)In order to further study the movement characteristics of the control rod,the understanding of the control system is increased,and the semi-physical simulation is carried out,and two schemes are adopted: the scheme based on the EPICS system and the OPC scheme based on the Windows system.In which,the EPICS scheme is easier to dock with the large-scale instruments,and the OPC scheme based on the Windows system is more prone to small-scale experiments.By interacting with MATLAB,the purpose of the control of the real control rod in-kind is achieved by the two schemes. |
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