Investigation of the Neptunium Behavior in the Electrolytic Reduction Separation of Uranium and Plutonium.

摘要

The electrolytic behavior of Np(V)-Np(V1) in HNO(sub 3) media was investigated. It was demonstrated experimentally that the electrolytic process is reversible. The reduction of Np(V) has very high overpotential. In double (region) compartment single stage electrolytic cell* with cathode potential of 700 mV (S.C.E), Np(V1) can be quantitatively reduced to Np(V) in 10 minutes. In the medium of 1.50 mol/1 HNO(sub 3), the reaction half-time for the electrolytic reduction of Np(V1) is about 1.5 minutes. It can be foreseen that the neptonium in the mixing-settling cell (M-S battery) is in the tetravalent state. The purpose, design and trial test of the electrolytic reduction mixing-settling cell with anode cathode co-chamber and the cold running of uranic acid are discussed. Such a cell was used in carry out the trial run of co-existing uranium, plutonium and neptonium, emphasizing the behavior of neptonium during the uranium and plutonium separation process. Experimental results indicate that the Pu recovery (yield) is 99.90-99.99%, the separation coefficient for Pu from U is 3900 (approximately)33000 and material balance of U, Pu, and acid is good. There is serious accumulation and inside recycling of neptonium in the cell. The neptonium in the cell is mainly in the tetravalent state. Under the conditions for U-Pu separation in 1B cell, it is very unlikely to recover neptonium quantitatively from the single product fluent.