Interactions of backfill materials with cesium in a bittern brine under repository conditions
The following potential backfill materials have been studied: phillipsite, clinoptilolite, mordenite, montmorillonites, vermiculites, chlorite, kaolinite, labradorite, and shales. Each of these was hydrothermally reacted with Cs/sub 2/MoO/sub 4/, a possible cesium phase in spent fuel elements, in the presence of a bittern brine at 200/sup 0/C for two months under a confining pressure of 300 bars. Analyses of the product solutions indicated that montmorillonites, vermiculites, and zeolites fixed (as determined by resistance to K+ washing) the greatest fractions of the added cesium while other minerals, labradorite, and shales fixed only about 10% of the added cesium. For example, montmorillonite from Arizona and phillipsite from California fixed 47 and 50%, respectively, of the cesium added. X-ray diffraction analysis of the solid products revealed that cesium was fixed in the interlayers of montmorillonite as indicated by the collapse of the c-spacing from 15.5 to 12.1 A. Cesium interaction with clinoptilolite and mordenite zeolites did not result in their alteration or in any new cesium minerals as observed by x-ray diffraction. The cesium aluminosilicate mineral, pollucite, was detected only with phillipsite-cesium interactions in brine unlike in the hydrothermal interaction of these materials with Cs/sub 2/MoO/sub 4/ in deionized water where the presence of pollucite was found earlier to be pervasive. Powellite, CaMoO/sub 4/, was the only new phase found in all these interactions by x-ray diffraction which resulted from the combination of calcium from brine with molybdenum from Cs/sub 2/MoO/sub 4/. Montmorillonites among clay minerals and zeolites such as clinoptilolite and mordenite seem to be the best backfill materials in salt.
- Research Organization:
- The Pennsylvania State University, Materials Research Laboratory, University Park, Pennsylvania 16802
- OSTI ID:
- 6993116
- Journal Information:
- Nucl. Technol.; (United States), Vol. 56:3
- Country of Publication:
- United States
- Language:
- English
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Hydrothermal reactions of clay minerals and shales with cesium phases from spent fuel elements
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Related Subjects
58 GEOSCIENCES
BACKFILLING
COMPARATIVE EVALUATIONS
MATERIALS TESTING
CESIUM COMPOUNDS
CHEMICAL REACTIONS
HYDROTHERMAL ALTERATION
CHLORITE MINERALS
CLINOPTILOLITE
KAOLINITE
MOLYBDATES
MONTMORILLONITE
MORDENITE
POLLUCITE
VERMICULITE
ZEOLITES
BRINES
POTASSIUM IONS
RADIOACTIVE WASTE DISPOSAL
UNDERGROUND DISPOSAL
WASTE-ROCK INTERACTIONS
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CESIUM SILICATES
CHARGED PARTICLES
CLAYS
COHERENT SCATTERING
DIFFRACTION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IONS
IRON COMPOUNDS
IRON SILICATES
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
MANAGEMENT
MATERIALS
MICA
MINERALS
MOLYBDENUM COMPOUNDS
OXYGEN COMPOUNDS
SCATTERING
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TESTING
TRANSITION ELEMENT COMPOUNDS
WASTE DISPOSAL
WASTE MANAGEMENT
052002* - Nuclear Fuels- Waste Disposal & Storage
580300 - Mineralogy
Petrology
& Rock Mechanics- (-1989)