In this study, the effects of the variables on sintering of simulated fuel to simulate the spent fuel are described. Mainly, the effects of compaction pressure, sintering temperature and time on the density of pellet are described. The experimental is performed with compaction pressure of 1 ton/$ extrm{cm}^2$~4 ton/$ extrm{cm}^2$, sintering temperature of 167$0^{circ}C$, 173$0^{circ}C$ and 178$0^{circ}C$ and sintering time of 4 hr, 8 hr and 24 hr. The green density of simulated fuel is proportional to the one third power of compaction pressure and the sintered density is 90.5~99.6% of theoretical density. The grain growth exponent and activation energy of simulated fuel is 2.5 and 287.97 kJ/mol, respectively.