Photochemical Oxidation of Neptunium(V) to Neptunium (VI) in Nitric Acid Solution Containing Reductants.

• WADA Yukio

  Nuclear Fuel Technology Development Division, Power Reactor and Nuclear Fuel Development Corporation

• MORIMOTO Kyouichi

  Nuclear Fuel Technology Development Division, Power Reactor and Nuclear Fuel Development Corporation

• GOIBUCHI Takayuki

  Nuclear Fuel Technology Development Division, Power Reactor and Nuclear Fuel Development Corporation

• TOMIYASU Hiroshi

  Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology

Abstract

The behavior of photochemical reactions of Np(V) in a nitric acid solution was studied under various test conditions as follows. As light sources, a mercury lamp and a semiconductor laser were used, and the light from the sources was irradiated on 2ml of neptunium nitric acid solutions in a quartz cell. The variables in these photochemical tests were the light irradiation rates (0.2 and 1.5W/cm²), the wavelength regions of the irradiation light (ultraviolet (UV) (250-400nm)), visible (400-600nm) and 980nm), the acidities of the nitric acid (1 and 3_M) and the kinds of addition reagents (hydroxylamine+hydrazine and urea). The photochemical changes in Np valences in the test solutions depending on the irradiation times were analyzed using a spectrophotometer. Based on these tests, the following results were obtained. <BR>• Neptunium(V) was photooxidized to Np(VI) by the irradiation of UV light on a nitric acid solution. <BR>• The higher the irradiation rate and the concentration of nitric acid, the easier the photo-oxidation reaction of Np(V) progressed. <BR>• The addition reagents influenced the oxidation reaction rate and the degrees of the progress in the photooxidation reaction of Np(V)→Np(VI). <BR>Based on the results of these tests, the quantitative control of the photooxidation reaction of Np(V) was found to have much potential for a valence adjustment by selecting the appropriate conditions of the UV irradiation rates, the acidity of HNO3 and the kinds of reductants.

Journal

• Journal of Nuclear Science and Technology

  Journal of Nuclear Science and Technology 32 (10), 1018-1026, 1995

  Atomic Energy Society of Japan

Keywords

• photochemical reactions
• nitric acid neptunium
• valence
• valence adjustment Purex process
• solvent extraction
• refining
• separation processes
• coextraction
• mercury lamp
• redox reactions
• photoexcitation
• photooxidation
• additives
• pH value

Details

• CRID: 1390282679072025216
• NII Article ID: 10002073400
• NII Book ID: AA00703720
• DOI: 10.3327/jnst.32.1018
• COI: 1:CAS:528:DyaK2MXpsValsrk%3D
• ISSN: 18811248
• ISSN: 00223131
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed