Study of Some Electrochemical Properties of Uranium in a Molten Fluoride Medium. Application to the Determination of the U(IV)/U(III) Ratio in the Fuel of a Fused Salt Breeder Reactor

摘要

The aim of this work is to check the possibility of determining the U(IV)/U(III) ratio by electrochemical techniques in the fused LiF-BeF sub 2 -ThF sub 4 mixture, solvent of a fused salt breeder reactor. The electrochemical properties of uranium systems were studied. The electrochemical reduction of U(IV) in LiF-BeF sub 2 -ThF sub 4 at 615 exp 0 C was studied by linear and cyclic potential variation voltamperometry, constant current voltamperometry and pulse voltamperometry (normal and derived mode). The results obtained at a molybdenum electrode show two successive electron transfers. The formation of U-Mo alloy is observed. The oxidation of U(IV) was observed at a vitreous carbon electrode. The results show that the uranium V formed is unstable, their interpretation suggesting that U(IV) dismutes into U(IV) and probably into gaseous UF sub 6 . In view of these results it was possible to determine the U(IV)/U(III) ratio by the use of the above electrochemical techniques. (Atomindex citation 11:521069)