Fatigue lifetime analysis on fuel cladding in marine reactor

Abstract Background: The maneuverability of nuclear-powered ships requires the sharp step change of the output power of the marine reactor, which causes fluctuation of fuel cladding temperature and coolant pressure. Since the enormous fluctuation leads to fatigue damage of cladding, it is important to analyze the fatigue lifetime of the fuel claddings in marine reactor. Purpose:The purpose is to analyze the effects of cladding temperature, coolant pressure, internal pressure of fuel rod and irradiation on the fatigue lifetime. Methods: By using ANSYS, the thermalmechanical behaviors of fuel rods in transient operation condition were simulated. The fatigue lifetime of cladding under different conditions was investigated, based on the design curves of the fatigue lifetime for zircaloy cladding. Results: The results indicate that the fatigue lifetime of the fuel cladding in marine reactor will reduce much in transient operation condition and irradiation can reduce fatigue lifetime of fuel cladding. The change of cladding temperature has little effect on the fatigue lifetime of cladding, compared with the change of coolant pressure. Conclusion: The fatigue damage in the fuel cladding in marine reactor is very serious. Suitable measures are suggested to take in order to reduce the fatigue damage of the cladding, under the premise of ensuring the maneuverability of ships. (authors)