Study of the stabilization of uranium dioxide fuel with carbon dioxide gas

Stabilization of the UO2 is an important step in the manufacturing process of fuel powder. After the reduction the UO2 powder is made chemically passive by slight oxidation to quite a large extent fixed by specifications that allow to storage powder till the sintering process is performed. In this work the UO2 powder is oxidized with a versatile automated physisorption/chemisorption analyzer as to generate adsorption isotherms with different pressures and temperatures of gaseous CO2 sequentially added to the samples. The reduction process is carried out in the same device as to obtain the same fluorite structure UO2.00 to perform control oxidation experiences so to get 2.04 and 2.06 UO2 powder. To check the extend of oxidation of UO2 powder, samples are characterized for O/U ratio analyses. The advantage of using CO2 is the possibility of high temperature controlled oxidative step which definitely is very beneficial for fuel manufacturing from an economic point of view. (author)