Investigation of Temperature Transient Response Characteristics of Ceramic Fuel Rod of Open-Cycled Reactor

To investigate the effects of the fuel material property on the temperature safety response characteristics of the new-designed open-cycled reactor with the air as the coolant, the geometric model of the annular fuel rod is built. The parameter model is developed based on the properties of the three types of ceramic material of nuclear fuel including the Uranium dioxide (UO 2 ), Uranium carbide (UC) and Uranium nitride (UN). The temperature transient response rule of the three kinds of fuel rods at the cases of reactor power step increase is obtained based on the fluid-structure coupling method. The temperature transient response characteristics of three types of ceramic fuel rods open-cycled reactor are analyzed. The numerical results reveal that the peak fuel temperature and the average fuel temperature increase significantly with the step increasing reactor power. The response time of the fuel rod with UC is the longest. The peak fuel temperature and the temperature difference of the fuel rod with UO 2 are the highest. The relative results can lay the theoretical foundation for the fuel material selection, structure design and the safety analysis of the open-cycled reactor.