Influence of redox environments on the geochemical behavior of radionuclides

Conference · Wed Jan 01 04:00:00 EST 1986 · Mater. Res. Soc. Symp. Proc.; (United States)

OSTI ID:5474157

Bidoglio, G; Avogadro, A; De Plano, A

Studies were carried out on the effect of redox conditions on the release from simulated vitrified HLW of Np-237, Pu-238 and Tc-99 and their migration through columns packed with site-specific porous material representative of clay and salt aquifers. Results obtained under oxic and anoxic conditions are compared. The release rates of Np, Pu and Tc were found to be lower in the absence of air than with oxygenated groundwaters. Speciation studies showed that neptunium and technetium were released in the oxidized forms Np(V) and Tc(VII) even under the investigated anoxic conditions where reduced species are thermodynamically more stable. In spite of that, a stronger interaction was observed when the leachate was passed through the column in the absence of air. A surface reduction process accounts for the observed behavior. Under more reducing conditions, plutonium appears to be present in the tetravalent state in colloidal form.

• Research Organization: Commission of the European Communities, Ispra, Italy
• OSTI ID: 5474157
• Report Number(s): CONF-850995-
• Conference Information: Journal Name: Mater. Res. Soc. Symp. Proc.; (United States) Journal Volume: 50
• Country of Publication: United States
• Language: English

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ACTINIDE ISOTOPES
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ALPHA DECAY RADIOISOTOPES
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BETA-MINUS DECAY RADIOISOTOPES
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INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
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SALT DEPOSITS
SOILS
SOLID WASTES
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UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
YEARS LIVING RADIOISOTOPES