Gamma uranium-molybdenum alloys has been considered as the fuel phase in plate type fuel elements for MTR reactors due to its performance under irradiation and metallurgical processing. To its usage as dispersion phase in aluminum matrix, a necessary step is the conversion of the as cast structure into powder, and the technique considered at IPEN / CNEN - Brazil was HDH (hydration-dehydration). This work has the aim to study the hydrogen incorporation by gamma-UMo alloys with 8% weight molybdenum. The samples were thermally treated under constant flow of hydrogen, for temperatures varying from 500oC up to 600oC and times of 1 to 4 hours. Some of the curves relating mass incorporation and time for the above temperatures were obtained, and the results related to its microstructures and ease of fragmentation.