Burnup determination by destructive method has been carried out as a part of the reprocessing tests with fuels irradiated in JRR-3.
Affer dissolution of the fuels, U was determined by potentiometric titration without separation, and Ru by α-counting with correction for isotopic composition. The isotopic composition of U and Pu was measured by mass spectrometry, while Cs was determined by γ-ray spectrometry after separation by co-precipitation.
The values of burnup obtained by isotopic analysis covering the thermal fission of 235U and 239Pu and fast fission of 238U are in good agreement with those obtained from 137Cs/U measurements.
