Influence of Air Oxidation on the Dissolution Behaviour of High Burn-Up LWR Spent Fuel
High burn-up (53.1 GWd/tU) Light Water Reactor spent fuel (UO(2) ) previously oxidized in flowing air at 270 degrees C to O/M ratios varying from 2.0 to 2.44 (U(4)O(9+x) ) was sequentially leached in deionized water at room temperature. A clear increase on the leaching rate of the matrix and the fission products with a high redox sensitivity, like technetium and molybdenum, was observed as a function of the degree of oxidation. This effect was not observed for plutonium and was limited to the initial step of the leaching. For the subsequent leaching periods, no relevant influence of the O/M ratio on the leaching rate could be detected. For the uranium matrix, a very low leaching rate (<3.10 (-7) g cm (-2)d(-1) ) was measured independent of O/M- ratio. In comparison to the matrix, all the fission products have higher release rates, suggesting a non-congruent leaching of elements segregated to the grain boundaries.
Bibliographic Reference: Article: Journal of Nuclear Materials, 1998
Record Number: 199910267 / Last updated on: 1999-03-12
Original language: en
Available languages: en