Determination of microgram masses of plutonium in spent fuel solutions by the method of coulometry with potential scanning

Coulometric method of direct remote determination of microgram masses of plutonium in spent fuel solutions is suggested. The analysed solution with nitric acid content of 1.5-3.0 mol/l is subjected to preliminary electrolysis for stabilizing the background current, then plutonium is reduced to plutonium (3) and then its oxidation to plutonium (4) is conducted at linear potential scanning with 0.2 mV/s speed. Calculation of plutonium mass in electrochemical cell is conducted according to the value of the maximal current of its oxidation. The relative standard deviation doesn't exceed 0.03 and 0.02 when determining 9 and 18 μg of plutonium respectively in spent fuel solutions. The lower boundary of the range of determined plutonium masses in the cell during the analysis of pure plutonium solutions is equal to 0.2 μg, during the analysis of spent fuel solutions - (0.4-0.5) μg