Preliminary assessment of radionuclide vapor phase transport in unsaturated tuff

Conference · Fri Aug 01 04:00:00 EDT 1986

OSTI ID:59995

Smith, D M; Updegraff, C D; Bonano, E J

The possibility of radionuclide migration in the vapor phase for unsaturated tuff has been investigated. Radionuclide movement could be the result of either aerosol migration or convection/diffusion of volatile species. A diffusion model for supersaturation of air in tuff groundwater indicates that there is no possibility of aerosol formation under expected repository conditions. An assessment of migration due to convection/diffusion requires solution of the coupled heat transfer-vapor flow-liquid flow problem around a waste canister. The TOUGH code has been used to calculate spatial and temporal distributions of liquid and vapor velocity, saturation and temperature for typical tuff formation properties. These distributions have been used to calculate the relative transport rates due to convection in the vapor phase as compared to the liquid phase. An analogous mobility ratio when diffusion dominates radionuclide transport has also been calculated. As a first order approximation, the maximum ratio of transport in the vapor phase to that in the liquid phase (irregardless of transport mechanism) is given by 1000K/sub w/ where K/sub w/ is the vapor-liquid distribution coefficient for the particular radionuclide.

• Research Organization: Pacific Northwest Lab., Richland, WA (United States); Univ. of New Mexico, Albuquerque
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 59995
• Report Number(s): NUREG/CP--0079; PNL-SA--13796; CONF-8505180--; ON: TI87002232
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
AQUIFERS
COMPUTER CODES
DIFFUSION
FLOW MODELS
FLOW RATE
GAS FLOW
GROUND WATER
HEAT TRANSFER
MATHEMATICAL MODELS
RADIOACTIVE WASTE FACILITIES
RADIONUCLIDE MIGRATION
TUFF
TWO-PHASE FLOW
VAPOR PRESSURE
VELOCITY
Yucca Mountain Project