Testing of uranium dioxide containing different levels of alpha activity under anaerobic and reducing conditions

Paper in proceeding, 2008

Samples of UO2 containing 5% 235U and 0, 5, or 10% 233U were tested in a dilute simulated groundwater using N 2 or H2 gas as the atmosphere. Some tests included metallic iron in the solution. Each test condition used samples run in triplicate for at least 21 days and each test condition was run for two consecutive test periods. The results show that the dissolution behavior of the samples is the same in both N2 and H2 atmospheres. The amount of U dissolved under these conditions clearly showed the enhancement of dissolution due to oxidation of the sample surface by radiolysis products for conditions without metallic Fe. When a piece of iron was included in the bottom of the test vessel, the amount of dissolution decreased dramatically indicating that the Fe(II) ions released from the corroding iron were able to react with most of the radiolysis products before they could oxidize the UO2 surface.