Fission gas diffusion coefficient calculation of irradiated Urania fuel using MCNP code

Annealing test of natural urania specimen was performed to obtain the fission gas release coefficient of Xe-133 after specimen was irradiated in HANARO reactor. Ge detector was used to get released Xe-13 peak in each 20 minutes up to 1 hour. To calculate real activity of released Xe-133, absolute efficiency of Ge detector was abtained through the measurement of Cs-137 reference source and MCNP code. As results of quantatative analysis, efficiency is 37.6%. Finally, fission gas release fraction was abtained but it was not adapted, because Temperatures was dependent as time. So new diffusion equation with time dependent temperature was introduced in this paper. It is available to get distribution of activation energy and pre-exponential factor in diffusion coeffient eqation in coincident with real release fraction. It was compareed with Turnbull's equation