The Study Of Thermo-Mechanical Properties For Multilayer Silicon Carbide Cladding In PWR

In recent years,the development of advanced nuclear fuel for light water reactor has become one of the research hotspots.Especially,after the fukushima accident in Japan,the world's major nuclear powers counties have speed up the fault-tolerant fuel(ATF)research and development process of the ATF,among them,the development of main direction that the ATF materials research is the fuel cladding.In the ATF research and development,it is extremely important to find alternative materials for the zirconium alloy cladding,which is one of the accident fault tolerant fuel(ATF)and has the potential to develop in the future.As a new type of cladding material,SiC exhibits a strong resistance to high temperature,radiation resistance and small neutron absorption cross section.It is obviously better than zirconium alloy cladding.In the process of research on SiC package shells,the design of multi-layer cladding with SiC composite materials and SiC has been the most recognized in the world.Various countries have studied multi-layer SiC cladding from different directions,but the domestic research and development of multi-layer SiC cladding is not enough,especially in calculation.The design of multi-layered silicon carbide(SiC)cladding is one of the research fields of the accident tolerant fuels(ATF)in pressurized water reactor(PWR).This paper mainly studies the stress distribution of the three-layered SiC cladding and duplex SiC cladding under steady-state operations.Based on the theory of elasticity of thin-walled cylindrical structures and Expansion principles,a model of multi-layered SiC cladding was developed to analyze the stress distributions under internal and external loadings,radial temperature gradients,and swelling.And ANSYS,MATLAB were applied to conduct the numerical simulation to get the result of stress distribution.The result means that the swelling is the main source of the total stress.Through Weibull distribution model,the failure probability in corresponding with stress distribution was obtained..The calculation result about the failure probability shows that duplex SiC cladding is superior than the three-layered SiC cladding.By analyzing the duplex SiC cladding under high burnable working conditions,the failure probability of SiC/SiCf layer in the inner layer is the smallest when the thickness ratio is 0.35,and the results of this paper provide some reference for future package design.