Investigation of alpha-radiation effect on valence state of actinoids

The spectrophotometric method was applied to study radiation-chemical oxidation of plutonium (3) in nitric acid solutions depending on nitric acid concentration (0.12-2.9 mole/l) and initial plutonium concentration (1.4-1. mole/l). Dose rate (3.2 Gy/s) of intense internal α-radiation was created by cerium-244 introduction into the solution. Plutonium (3) oxidation in subacid solutions is stated to take place only partially and to be followed by formation of plutonium (4) peroxide complex. Increase of nitric acid concentration results in increase of plutonium (3) oxidation rate and completeness. At nitric acid concentration > 0.5 mole/l formation of the peroxide complex is not observed, and the process of oxidation becomes autocatalytic. Nitric acid is shown to produce essential effect on kinetics of plutonium (3) oxidation