Thermal-gradient migration of brine inclusions in salt

Conference · Mon Feb 01 04:00:00 EST 1982

OSTI ID:5361750

Yagnik, S K

It has been proposed that the high level nuclear waste be buried deep underground in a suitable geologic formation. Natural salt deposits have been under active consideration as one of the geologic formations where a nuclear waste repository may be built in future. The salt deposits, however, are known to contain a small amount (about 0.5 vol.%) of water in the form of brine inclusions which are dispersed throughout the medium. The temperature gradients imposed by the heat generating nuclear waste will mobilize these brine inclusions. It is important to know the rate and the amount of brine accumulating at the waste packages to properly evaluate the performance of a nuclear waste repository. An extensive experimental investigation of the migration velocities of brine inclusions in synthetic single crystals of NaCl and in polycrystalline natural salt crystals has been conducted. The results show that in a salt repository the brine inclusions within a grain would move with the diffusion controlled velocities. The brine reaching a grain boundary may be swept across, if the thermal gradient is high enough. Grain boundaries in polycrystalline rock salt are apparently quite weak and open up due to drilling the hole for a waste canister and to the thermal stresses which accompany the thermal gradient produced by the heat generating waste. The enhanced porosity allows the water reaching the grain boundary to escape by a vapor transport process.

• Research Organization: Lawrence Berkeley Lab., CA (USA); California Univ., Berkeley (USA). Dept. of Nuclear Engineering
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5361750
• Report Number(s): LBL-14080; CONF-820359-1; ON: DE82013007
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
58 GEOSCIENCES
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
BRINES
CRYSTAL STRUCTURE
DIFFUSION
GEOLOGIC DEPOSITS
GRAIN BOUNDARIES
HIGH-LEVEL RADIOACTIVE WASTES
MANAGEMENT
MATERIALS
MICROSTRUCTURE
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTES
SALT DEPOSITS
TEMPERATURE EFFECTS
TEMPERATURE GRADIENTS
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES