Characterizing Radiation-Induced Chromium Redox Chemistry

Conference · Wed Aug 31 00:00:00 EDT 2022

OSTI ID:2282645

Danaher, Emma Grace ^[1]; Horne, Gregory P ^[1]; Conrad, Jacy Kathleen ^[1]

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1. Idaho National Laboratory

The redox behavior of Cr(III) and Cr(VI) in nuclear environments were studied by analyzing aqueous irradiated chromium ions using UV-Visible spectroscopy. The formation of different chromium oxidation states can occur through gamma radiolysis of chromium solutions. Characterization of radiation-induced chromium is not well understood, and yet important as chromium can make its way into the primary coolant of reactors because of the corrosion of stainless steel reactor components. Furthermore, Cr(VI) is toxic and not suitable for environmental release, therefore Cr speciation is important. Fricke dosimetry was performed to collect doses rates, specific extinction coefficients were obtained from various analytical methods for the two oxidation states of chromium. Chromium samples--conditioned at various pH's and concentration to understand the effects--were then irradiated using a Coblat-60 gamma irradiator. Three optical spectroscopy analytical methods were used , including direct oxidation state measurements and complexation by either EDTA or DPC. Complexation by EDTA was found to not be a reliable method. Radiolytic oxidation of Cr(III) to Cr(VI), and reduction of Cr(VI) to Cr(III) were clearly seen, except for Cr(III) samples were a pH less than or equal to 2, where no change occurred.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: 70
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 2282645
• Report Number(s): INL/EXP-22-68458-Rev000
• Conference Information: SULI Poster Presentation, Virtual, 08/31/2022 - 08/31/2022
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
Chromium
Gamma Irradiation
Oxidation States
Redox Behavior