Mechanism of unirradiated UO{sub 2} (s) dissolution in NaCl and MgCl{sub 2} brines at 25 C
- Univ. Politecnica de Catalunya, Barcelona (Spain). Dept. of Chemical Engineering
The dissolution of unirradiated UO{sub 2} (s) has been studied in NaCl and MgCl{sub 2} brines under both reducing and oxidizing conditions. The initial uranium release under reducing conditions has been attributed to the dissolution of an initial oxidized layer. The final uranium concentrations have been modeled by using the PHRQPITZ computer program giving the solubility of the solid phase UO{sub 2} (s). Under oxidizing conditions, the initial release is the sum of the oxidized layer dissolution and the oxidation/dissolution of the UO{sub 2}. The release rates calculated are 1.4 {times} 10{sup {minus}5} mol/m{sup 2} in NaCl-brine and 3.6 {times} 10{sup {minus}5} mol/m{sup 2} in MgCl{sub 2}-brine. After the initial release, uranium concentration in the NaCl-brine reaches a constant value, which has been attributed to the formation of a secondary solid phase. In MgCl{sub 2}-brine, the uranium concentration increases slowly indicating, in this case, no control by secondary phase formation.
- OSTI ID:
- 377965
- Report Number(s):
- CONF-941075--; ISBN 1-55899-253-7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
COMPUTERIZED SIMULATION
CORROSIVE EFFECTS
DISSOLUTION
EXPERIMENTAL DATA
HYDROGEN PEROXIDE
MAGNESIUM CHLORIDES
P CODES
PARTICLE SIZE
PH VALUE
RADIOACTIVE WASTE DISPOSAL
RADIOLYSIS
RADIONUCLIDE MIGRATION
REDOX REACTIONS
SODIUM CHLORIDES
SPENT FUELS
UNDERGROUND DISPOSAL
URANIUM DIOXIDE