Based on the light water cooled pressure tube blanket, the refueling strategies have been established using the spent nuclear fuel discharged from pressurized water reactor and natural uranium oxide, and detailed burnup calculations have been carried out. The numerical results show that only about 80 tonnes of spent nuclear fuel or natural uranium are needed every 1500 EFPD(Equivalent Full Power Day) with a 3000 MWth output and tritium self-sufficiency(TBR>1.20). Based on the equilibrium fuel cycle, the fuel costs of electricity of the blanket using different fuel are calculated, and the results are 1.82×10-3$/(k W·h) for the case of spent nuclear fuel, and 1.35×10-3$/(k W·h) for the case of using natural uranium, respectively.