Methyl-hydrazine Deoxidize Tc(VII) in Nitric Acid in Presence of U(VI) and Behavior of Technetium in the U/Pu Splitting Stage of APOR Process

The reaction between methyl-hydrazine and Tc(VII) in nitric acid in present of U(VI) was studied in this paper, the influence of acidity, methyl-hydrazine concentration, and temperature on the reaction was investigated meanwhile. Results showed that U(VI) can accelerate this reaction distinctly. When U(VI) concentration is 80 g/l, Tc(VII) can be deoxidized in 1.5 hours, on the contrary, the reaction will last 6 hours if there is no U(VI) in the system. The behavior of technetium in the U/Pu splitting stage was investigated using a multistage mixer-setter. In this experiment about 90% Tc(VII) was deoxidized within 3 stages when contacting with the reducing regent and uranium. Finally nearly 99.9% of technetium went to plutonium stream.