Results of Am isotopic ratio analysis in irradiated MOX fuels

Koyama, Shinichi  ; Osaka, Masahiko  ; Mitsugashira, Toshiaki; Konno, Koichi; Kajitani, Yukio

For analysis of a small quantity of americium, it is necessary to separate from curium which has similar chemical property. As a chemical separation method for americium, and curium, the oxidation of americium with pentavalent bismuth and subsequent co-precipitation of trivalent curium with BIPO were applied to analyze americium in irradiated MOX fuels which contained about 3Owt% plutonium and 0.9wt% Am before irradiation and were irradiated up to 26.2GWd/t in the experimental fast reactor Joyo. The purpose of this study is to measure isotopic ratio of americium and to evaluate the change of isotopic ratio with irradiation. Following results are obtained in this study, (1)The isotopic ratio of americium (Am, Am and Am) can be analyzed in the MOX fuels by isolating americium. The isotopic ratio of Am and Am increases up to 0.62at% and 0.82at% at maximum burnup, respectively. (2)The results of isotopic analysis indicates that the contents of Am decreases, whereas Am, Am increase linearly with increasing burnup.