Preparation and melting of uranium from U 3O 8

Abstract

In this paper, we report on the preparation and melting of uranium in association with a spent nuclear fuel conditioning process. U 3O 8 powder was electrochemically reduced in a mixture of molten LiCl–Li 2O (∼3 wt.% of Li 2O in LiCl) at 650 °C resulting in the formation of uranium and Li 2O with a yield of >99%. When the powder of uranium with a residual LiCl–Li 2O salt was heated in order to melt the metal, the uranium oxidation to UO 2 due to the reaction with Li 2O was observed. We were able to synthesize FeU 6 by using a Fe based cathode during the U 3O 8 reduction procedure. FeU 6 could be melted to below the temperatures where the oxidation of uranium by Li 2O occurred. The idea of compound formation and melting is applicable to the melting and casting of a spent nuclear fuel which contains oxidative residual salts due to its conditioning in a molten salt.