Oxidation behavior of spent UO2 fuel

To support dry storage technology oxidation tests were conducted with light water reactor spent fuel. The initial rate of weight gain for spent fuel was up to 50 times greater than the initial rate for nonirradiated pellets. Spent fuel formed measurable U4O9+x particulates at weight gains significantly higher than those at which the nonirradiated pellets formed U3O8 powder. Initial test results on three types of pressurized water reactor (PWR) spent fuel indicated that fuel type had a significant influence on weight gain. Additional tests were performed at temperature levels from 135 to 2300C on fuel with burnups from 8 to 34 GWd/tonne U irradiated in five different reactors. The tests were conducted in static air at controlled moisture levels in a 105 R/h gamma field. In the United States, dry storage of light water reactor (LWR) spent fuel at reactor sites is a licensed alternative to storage in water pools