Performance sensitivity analysis of the repository seals subsystem: Access drift study
This study conservatively assesses the sensitivity of radionuclide releases into repository shafts from access drifts backfilled with only crushed basalt, only 75% crushed basalt-25% bentonite, or a combination of these backfills. The parameters for which sensitivity was assessed are (1) lengths of drift segments backfilled with crushed basalt and crushed basalt bentonite, (2) hydraulic conductivities of crushed basalt backfill, crushed basalt-bentonite backfill and the damaged rock zone (DRZ), (3) radiogenic heat load, (4) container life, and (5) effects of groundwater pumping. Radionuclide flux ratio is selected as the basis of the performance goal by which drift seals performance is measured. Radionuclide flux ratio is defined as the mass of radionuclides entering the base of the shaft divided by the mass of radionuclides transported out of the two modeled waste emplacement rooms. The performance goal assigned to drift seals is to limit the radionuclide flux ratio to 1% or less. Although drifts backfilled from shaft to emplacement room with the 75% crushed basalt-25% bentonite mixture are shown to have the least radionuclide flux ratio, the performance of a 61-m (200-ft) length of backfilled drift, equally divided between drifts on opposite sides of the shaft, is substantially better than that required by the performance goal. Such backfilled drift segments are several orders of magnitude less permeable than drifts filled only with crushed basalt. 21 refs., 23 figs., 16 tabs.
- Research Organization:
- Rockwell International Corp., Richland, WA (USA). Rockwell Hanford Operations
- Sponsoring Organization:
- DOE/RW
- DOE Contract Number:
- AC06-77RL01030
- OSTI ID:
- 5201178
- Report Number(s):
- RHO-BWI-TI-322; ON: TI90005911
- Country of Publication:
- United States
- Language:
- English
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053000 -- Nuclear Fuels-- Environmental Aspects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BACKFILLING
BASALT
COMPILED DATA
CONTAINERS
DATA
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL TRANSPORT
FORECASTING
GROUND WATER
HANFORD RESERVATION
HIGH-LEVEL RADIOACTIVE WASTES
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
INFORMATION
MANAGEMENT
MASS TRANSFER
MATERIALS
MINE SHAFTS
NATIONAL ORGANIZATIONS
NUMERICAL DATA
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE MANAGEMENT
RADIOACTIVE WASTES
RADIOECOLOGICAL CONCENTRATION
RADIONUCLIDE MIGRATION
ROCKS
SEALS
SHAFT EXCAVATIONS
UNDERGROUND DISPOSAL
US DOE
US ERDA
US ORGANIZATIONS
VOLCANIC ROCKS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
WATER