Post-irradiation characterization of low burn-up UZr metal fuel: Evaluation of uranium, zirconium, fission and activation products

Irradiation of U-6 wt.% Zr was carried out to understand the fuel behavior and performance under operational conditions in fast breeder test reactor. Understanding the transformation of uranium, as well as the formation and distribution of fission and activation products, is crucial for assessing fuel performance. This study focuses on the analytical measurement of U and Zr using X-ray fluorescence and the gamma spectrometric determination of fission and activation products in the irradiated fuel dissolver solution. Being a low burn-up fuel, the change in the concentration of U and Zr was marginal. Some of the major long-lived fission products such as 106Ru, 125Sb, 137Cs, 134Cs, 144Ce-144Pr, 154Eu etc. were estimated. Additionally, minor actinides like 241Am were estimated by employing gamma spectral interference corrections from 155Eu, while 239Pu was determined following its separation from the dissolver solution using tri-n-butyl phosphate. Total Pu was also estimated using isotopic composition data of plutonium arrived using mass spectrometry measurements.