Redox equilibrium of U 4+/U 3+ in molten NaCl-2CsCl by UV-Vis spectrophotometry and cyclic voltammetry

Takayuki Nagai, Akihiro Uehara, Toshiyuki Fujii, Osamu Shirai, Nobuaki Sato, Hajimu Yamana

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42 Citations (Scopus)


In order to investigate the redox equilibrium of uranium ions in molten NaCl-2CsCl, UV-Vis absorption spectrophotometry measurements were performed for U 4+ and U 3+ in molten NaCl-2CsCl at 923 K under simultaneous electrolytic control of their ratio. Prominent absorption bands at 480 and 570 nm were assigned to U 3+, and their molar absorptivities were determined to be 1,260±42 and 963±32 mol -1./.cm -1 respectively. From the dependence of the rest potential of the melt on the spectrophotometrically determined ratio of [U 4+]/[U 3+], the standard redox potential of the couple U 4+/U 3+ at 923K was determined to be -1.481±0.004V vs. Cl 2/Cl -. Cyclic voltammetry measurements were carried out for the couple U 4+/U 3+, and the results agreed well with this standard redox potential value. By the results of cyclic voltammetry, a temperature dependence of the standard redox potential was found to be -2.094+6.639×10 -4T (7=823-923 K).

Original languageEnglish
Pages (from-to)1025-1031
Number of pages7
Journaljournal of nuclear science and technology
Issue number12
Publication statusPublished - 2005 Dec


  • Absorption spectrophotometry
  • Cesium chloride
  • Cyclic voltammetry
  • Dry reprocessing
  • Electro-winning method
  • Molar absorptivity
  • Molten salt
  • Redox potential
  • Sodium chloride
  • Uranium ion

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering

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