Numerical Simulation Research on Irradiation-Thermal-Mechanical Behavior of CDM Fuel in Different Types of Reactors

Abstract The ceramic dispersion microencapsulated (CDM) fuels have high tolerance of accidents, and are regarded as promising candidates for the light water reactors. During irradiation, the parts in the CDM fuel may experience extreme irradiation-related irradiation-thermal-mechanical behavior. The buffer layer, which provide free volume for gaseous fission products and absorb kernel swelling, will firstly shrink during the early lifetime, and will re-contact to the IPyC layer. The re-contact of the two layers will cause high circle tensile stress in the IPyC layer, which may lead to the failure of the microencapsulated particle. In order to study the in-pile performance of the CDM fuels, and the possible application of the CDM fuels in other kind of reactors, such as the high flux reactor (HFR), the ADS reactor, and RERTR research and testing reactor, a series of researches are needed. Because of the economic efficiency of in-pile tests, researches of combined with numerical simulation could be an effective method for the study of the in-pile behaviors, the performance evaluation and the optimum design of the CDM fuel. In this research, a 3-D numerical simulation model of the in-pile behaviors of CDM fuel particles with ceramic matrix is built. Different irradiation conditions based on various type of reactors are introduced into the simulation of CDM fuel in-pile irradiation-thermal-mechanical behavior. The simulation results and the failure evaluation of the CDM fuels are discussed.