Isotope correlations for determining the isotopic composition of plutonium in high burnup pressurized water reactor (PWR) samples

Correlations among the alpha activity ratios of 238Pu/(239Pu+240Pu), the alpha specific activities of Pu and the atom % abundances of Pu isotopes were derived for the plutonium samples obtained from high burnup fuel samples from pressurized water reactors. Using the alpha activity ratios of 238Pu/(239Pu+240Pu) determined by alpha spectrometry, the alpha specific activities of Pu as well as the atom % abundances of the plutonium isotopes in the unknown samples were calculated without depending on mass spectrometry. The calculated alpha specific activities of Pu agreed with those determined by experiment within 2%, and the atom % abundances of the Pu isotopes agreed within 4% for 238Pu, 5% for 239Pu, 7% for 240Pu and 5% for 242Pu, respectively. In addition, an attempt was made to elucidate a correlation between the fuel burnup and the alpha activity ratio of 238Pu/(239Pu+240Pu) at a range of the burnup from 35.5 to 62.9 GWd/MtU.