ACCURATE DETERMINATION OF PLUTONIUM CONTENT IN PLUTONIUM SULFATE TETRAHYDRATE BY CONTROLLED POTENTIAL COULOMETRY

The accurate determination of Pu content in plutonium sulfate tetrahydrate by controlled potential coulometry is described. The plutonium sulfate tetrahydrate is dissolved in 2.5 mol/l HNO_3. A solution of l mol/l nitric acid is used as the electrolyte and netted gold as the working electrode. The Pu (Ⅳ) is reduced to Pu (Ⅲ) by maintaining the control potential at 0. 455 V (SCE), and then oxidation of Pu (Ⅲ) to Pu (Ⅳ) is accomplished by maintaining the control potential at 0.895 V (SCE) until the cell current level dropped down to less 20 μA. The amount of plutonium to be assaied is about 6 mg and the method shows a precision of 0.046% relative standard deviation, RSD, with no significant bias.