Long-term performance of spent fuel waste forms

Technical Report · Tue Sep 01 04:00:00 EDT 1987

OSTI ID:5964976

Means, J L; Markworth, A J; McCoy, J K; Failey, M P; Stenhouse, M J; Kohli, R; Taylor, G C

This report investigates the leaching/dissolution characteristics of spent fuel in simulated groundwaters. Experiments evaluated the leaching of unirradiated UO/sub 2/ in simulated groundwaters both in the presence and absence of an external radiation field. Other experiments characterized the dissolution behavior of spent fuel under the same conditions as for UO/sub 2/. Leach data were interpreted in terms of rates and mechanisms of radionuclide release, thus providing insight on leach behavior under realistic repository conditions. Uranium release from both unirradiated and irradiated UO/sub 2/ appeared to be solubility controlled, with only minor leachate compositional effects on the uranium concentrations. When leached in the presence of a radiation field, unirradiated UO/sub 2/ produced elevated uranium concentrations only in the brine leachates. The leaching of both cesium and iodine from spent fuel was rapid and linear with the surface-area-to-volume (S/V) ratio. Similar to cesium and iodine, strontium release was nearly proportional to S/V. However, unlike cesium and iodine, strontium release was strongly affected by leachate composition, with greater release associated with lower pH. A model describing the kinetics of spent fuel/UO/sub 2/ dissolution was developed, complementing the experimental studies. For fixed values of the time constant and kinetic exponent, the model predicts that the effect of water chemistry on spent fuel dissolution is largely limited to affecting the saturation concentration of uranium in the aqueous solution. This result contrasts sharply with results obtained previously for glass dissolution. 59 refs., 34 figs., 13 tabs.

• Research Organization: Battelle Columbus Div., OH (USA); Nuclear Regulatory Commission, Washington, DC (USA). Div. of Engineering
• OSTI ID: 5964976
• Report Number(s): NUREG/CR-4954; BMI-2154; ON: TI88900069
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
053000 -- Nuclear Fuels-- Environmental Aspects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
510300 -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
DISSOLUTION
ENERGY SOURCES
ENVIRONMENTAL TRANSPORT
FUELS
GROUND WATER
HIGH-LEVEL RADIOACTIVE WASTES
HYDROGEN COMPOUNDS
LEACHING
MANAGEMENT
MASS TRANSFER
MATERIALS
NUCLEAR FUELS
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
RADIONUCLIDE MIGRATION
REACTOR MATERIALS
SEPARATION PROCESSES
SPENT FUEL STORAGE
SPENT FUELS
STORAGE
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE FORMS
WASTE MANAGEMENT
WASTES
WATER