Numerical Simulation And Experimental Study Of Metal C-ring For Reactor Pressure Vessel

Nuclear reactor pressure vessel(RPV)is the primary loop coolant pressure boundary barrier in the basis of vital components,belonging to the nuclear safety class I equipment,which has the characteristics of high temperature and high pressure,radioactive,and the sealing performance will directly affect the normal operation of the reactor.Reactor pressure vessel flange seal which is between the lid and container is one of the key technologies,this seal structure is mainly used double-channel metal O-ring or metal C-ring.Because the metal C-ring in the use of performance and reliability are superior to O-ring,so the million kilowatt of pressure vessel using metal C-ring as seal.The sealing performance of metal C-ring will be directly related to the whole sealing reliability of the reactor pressure vessel,so the research on the deformation characteristics and mechanical behavior of metal C-ring to improve the sealing performance and ensure the reactor pressure vessel has great significance,and providing certain reference basis for the localization of metal C-ring in nuclear reactor.The spring energized metal C-ring was composed of outer layer,inner cladding layer and helical spring which's materials were silver layer,Inconel600 alloy and Inconel X750 alloy,respectively.A three dimensional nonlinear elastoplastic finite element model of the reactor pressure vessel metal C-ring had built.The finite element software Abaqus was used for numerical simulating and structure optimizing the mechanical properties and sealing performance of metal C-ring.Then the correctness of the finite element analysis was verified by sealing test equipment and the 3D profilometer,such as compression resilience test,the three-dimensional morphology experiment of sealing surface and shape contour of sealing ring.The analysis of mechanical properties,sealing performance and structure optimization of metal C-ring were finished.The effect of the structure parameters of C-ring(outer diameter of C-ring,silver thickness,coating layer thickness,opening angle,spring pitch,spring wire diameter,medium diameter of spring coil)on the mechanical property and sealing performance of metal C-ring seal were studied,and the reference value of C-ring structure sizes were given.The effect of compression ratio,medium pressure and deformation of flanges on the sealing performance of C-ring were analyzed.The results had showed that the best compression ratio of the C-ring is 10%.As the effect of medium pressure on minimum contact stress of C-ring sealing surface is small,the influence of medium pressure on sealing performance of C-ring could be ignored when analysis the sealing performance of C-ring.Deformation of flanges caused uneven force on double metal C-ring that the stress and strain on outer ring was greater than inner ring.On the basis of C-ring structure parameters and operation parameters optimization,compression resilience experiment,air tightness,hot and cold circulating water pressure experiment(normal temperature,high temperature)were completed,further verifing the structure optimized C-ring was suitable for the service condition of million kilowatt nuclear reactor pressure vessel(RPV).