Development of backfill material as an engineered barrier in the waste package system- Interim topical report
A backfill barrier, emplaced between the containerized waste and the host rock, can both protect the other engineered barriers and act as a primary barrier to the release of radionuclides from the waste package. Attributes that a backfill should provide in order to carry out its required function have been identified. Primary attributes are those that have a direct effect upon the release and transport of radionuclides from the waste package. Supportive attributes do not directly affect radionuclide release but are necessary to support the primary attributes. The primary attributes, in order of importance, are: minimize (retard or exclude) the migration of ground water between the host rock and the waste canister system; retard the migration of selected chemical species (corrosive species and radionuclides) in the ground water; control the Eh and pH of the ground water within the waste-package environment. The supportive attributes are: self-seal any cracks or discontinuities in the backfill or interfacing host geology; retain performance properties at all repository temperatures; retain peformance properties during and after receiving repository levels of gamma radiation; conduct heat from the canister system to the host geology; retain mechanical properties and provide resistance to applied mechanical forces; retain morphological stability and compatibility with structural barriers and with the host geology for required period of time. Screening and selection of candidate backfill materials has resulted in a preliminary list of materials for testing. Primary emphasis has been placed on sodium and calcium bentonites and zeolites used in conjunction with quartz sand or crushed host rock. Preliminary laboratory studies have concentrated on permeability, sorption, swelling pressure, and compaction properties of candidate backfill materials.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 5839515
- Report Number(s):
- PNL-3873; ON: DE82000937; TRN: 82-001606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
RADIOACTIVE WASTE DISPOSAL
BACKFILLING
ENGINEERED SAFETY SYSTEMS
BENTONITE
COMPARATIVE EVALUATIONS
GEOLOGIC DEPOSITS
GROUND WATER
PERMEABILITY
PH VALUE
QUARTZ
RADIONUCLIDE MIGRATION
ROCKS
SORPTIVE PROPERTIES
SWELLING
TESTING
UNDERGROUND DISPOSAL
ZEOLITES
CHALCOGENIDES
ENVIRONMENTAL TRANSPORT
HYDROGEN COMPOUNDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MANAGEMENT
MASS TRANSFER
MATERIALS
MINERALS
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
SURFACE PROPERTIES
WASTE DISPOSAL
WASTE MANAGEMENT
WATER
052002* - Nuclear Fuels- Waste Disposal & Storage
360603 - Materials- Properties