Amount of nuclides constituting PWR spent fuels

Destructive analysis of nuclides in PWR spent fuels whose burnup rates were between 6.9 and 32.1 GWd/MTU was carried out. The measurements for thirty nuclides of uranium, transuranium and fission product elements were performed by mass spectrometry, α-ray and γ-ray spectrometry. The amounts of nuclides observed were compared with those calculated by two burnup codes, ORIGEN2 and SRAC-FPGS, on the basis of the evaluation of relative percent differences. Although the amounts of 235U, 236U and 237Np as well as 143Nd, 144Nd, 145Nd, 146Nd, 148Nd, 150Nd and 137Cs calculated by ORIGEN2 agreed quite well with those observed, the results of 238Pu, 242Pu, 243Am, and 244Cm calculated by ORIGEN2 were considerably lower than those observed, which can be mainly explained by weak depletion of 238U. There were remarkable discrepancies between the results observed and calculated for 232U, 125Sb and 154Eu, which may be attributable to incorrect production chain and/or nuclear data used. On the other hand, the results calculated by SRAC-FPGS were in good agreement with those observed except for 243Am, 106Ru and 134Cs. Furthermore, it was found that the relative percent differences for 244Cm, 125Sb and 154Eu obtained with codes of both ORIGEN2 and SRAC-FPGS depended on burnup. (orig.)