VALIDATION OF SWAT FOR BURNUP CREDIT PROBLEMS BY ANALYSIS OF PIE OF 17X17 PWR FUEL ASSEMBLY

For adopting bumup credit in transport or storage of spent fuel(SF), development of a reliable bumup calculation code is crucial. For this purpose, data of Post Irradiation Examination (PIE) (Naito et al., 1993) have been extensively analyzed to evaluate accuracy of bum up calculation codes for a 14 X 14 or 15 X 15 PWR fuel assembly(Suyama et al., 1994). For example, PIE at TRINO in Italy has been one of the most famous ones for this purpose. Moreover, PIE at Mihama-3 PWR in Japan was disclosed recently, and can be used for the validation of bumup codes. However, design of current PWR fuel assembly has shifted, i.e ., a 17 X 17 type fuel assembly is widely used. This means that we should validate our bumup codes for this new-designed assembly. From 1995, PIE for a 17 X 17 fuel assembly irradiated in a Japanese PWR has been made by a group of Analytical Chemistry Laboratory of Japan Atomic Energy Research Institute (JAERI). Any PIE and results of analysis have not been opened for this type of assembly in the world. This study shows results of analysis of this latest PIE with SW AT(Suyama et al.,1996) and ORIGEN2.1 (Croff,l983). SWAT is a integrated bumup code system that has been developed by Tohoku University and JAERI. The results show that SWAT can more precisely predict nuclide composition of latest PWR assembly than ORIGEN2.1.