Dry uranium tetrafluoride process preparation using the uranium hexafluoride reconversion process effluents

It is a well known fact that the use of uranium tetrafluoride allows flexibility in the production of uranium silicide and uranium oxide fuel. To its obtention there are two conventional routes, the one which reduces uranium from the UF6 hydrolysis solution with stannous chloride, and the hydrofluorination of a solid uranium dioxide. In this work we are introducing a third and a dry way route, mainly utilized to the recovery of uranium from the liquid effluents generated in the uranium hexafluoride reconversion process, at IPEN/CNEN-SP. Working in the liquid phase, this route comprises the recuperation of ammonium fluoride by NH4HF2 precipitation. Working with the solid residues, the crystallized bifluoride is added to the solid UO2, which comes from the U miniplates recovery, also to its conversion in a solid state reaction, to obtain UF4. That returns to the process of metallic uranium production unity to the U3Si2 obtention. This fuel is considered in IPEN-CNEN/SP as the high density fuel phase for IEA-R1m reactor, which will replace the former low density U3O8-Al fuel. (author)