Structure Analysis And Simulation Of In-Vessel Fuel Handling System For Accelerator Driven Lead-based Reactor

Accelerator Driven subcritical System(ADS)is an advanced system for transmutation of the long-lived radioactive nuclear wastes,nuclear fuel breeding as well as nuclear energy generation.ADS reactor has an inherent characteristic that the accelerator proton beam tube runs through the pile cap into the core,connecting with the target located in the center of the core.It causes the inner structure complex and the space limited for fuel handling.Therefore,the In-vessel Fuel Handling System(IVFHS)and the accelerator proton beam tube must be well coupled.And the IVFHS can reach all the points and realize refueling function in high temperature,sealed,opaque liquid lead-bismuth alloy,which are the key technologies of the IVFHS to realize the automatic refueling function in lead-based ADS reactor.This paper takes China Lead-based Research Reactor(CLEAR-1)as a reference case for lead-based ADS reactor.According to the refueling requirements,the design of double rotating plugs and split-type center column scheme of the IVFHS was proposed.The system kinetic equations and velocity Jacobi matrix were deduced based on the kinematic analysis.The structural style and parameters of IVFHS were checked by the computer simulation and verified by the principle prototype.It had a good coupling with other systems in the vessel.The static analysis and kinematics simulation of the transfer gripper were carried out and tested on the engineering prototype.The simulation and test results verified the rationality and accuracy of the structure design.It could provide some guidance for developing the refueling system in high temperature and liquid metal cooled reactor,especially in ADS.The main research contents and innovations are as follows:A kind of positioning method by the composite rotation of double rotating plugs is proposed.One rod refueling mechanism with five degrees of freedom(5-DOF)was developed as per the specific requirements.The simulation results verified that the IVFHS can cover all the assemblies and the scheme solves the problem of the automatic refueling that caused by the proton beam tube.Also,it meets the requirement of the experimental flexibility for a compact and integrated ADS system.A kind of transfer machine combining the special rod drive and rigid self-lock was designed.The analysis and simulation of the gripper in the typical working conditions are carried out.The key structural parameters were selected for static analysis.A virtual prototype was developed and the kinematics simulation was carried out.The resultsshow that the movement of the gripper is smooth and flexible in its working range of motion.It solves the stability and reliability problems of the transfer machine in high temperature and opaque heavy liquid metal environment.It ensures the safety of fuel assembly during transportation.An integrated validation and testing platform of refueling mechanism for lead-based ADS reactor was developed.The principle prototype and engineering prototype of the refueling mechanism were developed on the basis of theoretical analysis and simulation.The experiment and testing of key refueling technologies were carried out,such as location,traversing,grasping and high temperature performance.The testing results show that the refueling mechanism can precisely locate and replace all assemblies in the core.The grasping performance in high temperature lead-bismuth alloy is good.The validation of the feasibility was completed and the automatic refueling problem covering full core was solved.It is of valuable reference for the actual engineering design and production of IVFHS.