Nuclear Criticality of Transportation and Storage Cask of Spent Fuel in WWER-1000 Reactor for Two Modes of Burn-Up and Fresh Fuels

One of the problems of nuclear power plants beside electricity generation is the product of spent fuels that should be managed in a proper manner. Therefore, some countries have chosen dry storage for their spent fuel in which double purposed casks are employed for transportation and storage of these spent fuels. TK-13 is one of the casks used for transportation and storage of spent fuels in WWER-1000 reactor which can transport and store 12 assemblies of spent fuels. In this study, the safety of nuclear criticality of inner holding basket for the fuel in two cases of burn-up and fresh fuels by MCNPX2.6 and ORIGEN2.1 codes has been calculated and analyzed. According to results of two modes of burn-up and fresh fuels show that casks with 66 cm radius and 28 cm of pitch and inner holding baskets made of bore bearing and bore less steel, respectively fulfill non-criticality of system.