Dissolution kinetics of UO sub 2 : Flow-through tests on UO sub 2. 00 pellets and polycrystalline schoepite samples in oxygenated, carbonate/bicarbonate buffer solutions at 25 degree C

Conference · Tue Oct 01 00:00:00 EDT 1991

OSTI ID:6021724

Nguyen, S N; Weed, H C; Leider, H R; Stout, R B

The modelling of radionuclide release from waste forms is an important part of the performance assessment of a potential, high-level radioactive waste repository. Since spent fuel consists of UO{sub 2} containing actinide elements and other fission products, it is necessary to determine the principal parameters affecting UO{sub 2} dissolution and quantify their effects on the dissolution rate before any prediction of long term release rates of radionuclides from the spent fuel can be made. As part of a complex matrix to determine the dissolution kinetics of UO{sub 2} as a function of time, pH, carbonate/bicarbonate concentration and oxygen activity, we have measured the dissolution rates at 25{degrees} C of: (1) UO{sub 2} pellets; (2) UO{sub 2.00} powder and (3) synthetic dehydrated schoepite, UO{sub 3}.H{sub 2}O using a single-pass flow through system in an argon-atmosphere glove box. Carbonate, carbonate/bicarbonate, and bicarbonate buffers with concentrations ranging from 0.0002 M to 0.02 M and pH values form 8 to 11 have been used. Argon gas mixtures containing oxygen (from 0.002 to 0.2 atm) and carbon dioxide (from 0 to 0.011 atm) were bubbled through the buffers to stabilize their pH values. 12 refs., 2 tabs.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6021724
• Report Number(s): UCRL-JC-107478; CONF-911109-3; ON: DE92002667
• Resource Relation: Conference: Fall meeting of the European Materials Research Society, Strasbourg (France), 5-8 Nov 1991
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
ACID CARBONATES
BUFFERS
DISSOLUTION
CHEMICAL REACTION KINETICS
OXYGEN
THERMODYNAMIC ACTIVITY
URANIUM DIOXIDE
LEACHING
PH VALUE
RADIONUCLIDE MIGRATION
SCHOEPITE
SPENT FUELS
WASTE FORMS
ACTINIDE COMPOUNDS
CHALCOGENIDES
ELEMENTS
ENERGY SOURCES
ENVIRONMENTAL TRANSPORT
FUELS
KINETICS
MASS TRANSFER
MATERIALS
MINERALS
NONMETALS
NUCLEAR FUELS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE MINERALS
REACTION KINETICS
REACTOR MATERIALS
SEPARATION PROCESSES
URANIUM COMPOUNDS
URANIUM MINERALS
URANIUM OXIDES
052002* - Nuclear Fuels- Waste Disposal & Storage
540130 - Environment
Atmospheric- Radioactive Materials Monitoring & Transport- (1990-)
053000 - Nuclear Fuels- Environmental Aspects