| Nuclear reactor control rod is the key equipment to control reactor chain reaction rate and compensate fuel consumption,also known as reactor safety rod.The reactor pressure vessel is an airtight container for placing nuclear reactors and bearing huge pressure.Both are the key equipment for safe operation of nuclear power plants and are connected by pipe seats welded on the top cover of pressure vessels.As a pipe seat directly connected to the pressure vessel,its sealing performance directly affects the normal operation of the reactor.Flexible graphite gasket with its excellent chemical stability,soft resilience,radiation resistance and high and low temperature resistance,successfully meet the requirements of nuclear grade seal.Firstly,using ANSYS Workbench finite element analysis software and bilinear isotropic strengthening model,this paper makes a mechanical analysis on the deformation characteristics of the gasket,studies the mechanical characteristics of the flexible graphite filler gasket under different compression ratio,size specifications and side clearance,and obtains its load deformation curve and stress distribution curve.The peak contact pressure and maximum plastic deformation of flexible graphite packing gasket are experimentally studied,and the errors between experimental and simulation results are analyzed to verify the accuracy of bilinear isotropic strengthening model in simulating the deformation characteristics of flexible graphite packing gasket.Secondly,through the ANSYS Workbench finite element analysis software,the mechanical analysis model of bonded flexible graphite gasket is established,the contact relationship between metal bonded and flexible graphite filler is analyzed,the influence law of bonded structure,bonded thickness and bonded quantity on the deformation characteristics of bonded gasket is studied,and the deformation curve and stress distribution curve of bonded gasket are obtained,The stress changes on the edge corner of the edging structure and the sealing surface of graphite packing are analyzed to verify the effectiveness of the edging structure in solving the tear problem of the edge corner of the gasket.Finally,using the comprehensive performance test bench of static sealing gasket,the surface state of packing gasket and wrapped gasket after the test is studied,the causes of the error between the test and simulation results are analyzed,and the reliability of the mechanical analysis model of wrapped gasket is judged.According to the initial structure scheme of the lead bismuth reactor socket,the sealing structure of the socket flange is designed,the air tightness test-bed of the wrapped gasket is built,the leakage data of the wrapped gasket in the air pressure test and temperature pressure cycle test are obtained,and the sealing reliability of the wrapped flexible graphite packing gasket is judged. |
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