Ceramic phases for immobilization of /sup 129/I. [Sodalite and boracite]
Materials for ultimate disposal of /sup 129/I have been studied. At present, iodide-sodalite, though not ideal, appears to be the best material for /sup 129/I immobilization from the aspects of ease of preparation, thermal stability, cost of materials, and leach resistance. Good consolidation of the material was achieved by sintering in air at 1000 to 1200/sup 0/C, but the iodine content was significantly below stoichiometric expectations. Hot aqueous media preferentially removed iodine, apparently by OH/sup -/ substitution in near-neutral solutions, and I reversible reaction Cl/sup -/ exchange occurred in brine. Alternation of the sodalite also took place. Soxhlet leach rates were about 5 x 10/sup -4/ g/cm/sup 2/-day by total weight loss, but physical weathering contributed significantly to this value. Moderate doses of radiation had no observable deleterious structural effects. Iodoboracites seemingly cannot be prepared by ceramic or nonhydrothermal wet chemical techniques. Fe-iodoboracite has inferior thermal stability to iodide-sodalite and was completely altered to hematite after treatment at 200/sup 0/C in deionized water. Silver zeolites retained some iodine in the form of crystalline ..cap alpha..-AgI at temperatures up to 1300/sup 0/C even though heating above approx. 700/sup 0/C altered the alumino-silicate framework. However, some of the iodine appeared to be present as soluble iodine, even in heated materials. Treatment at 200/sup 0/C in deionized water or 2M NaCl significantly decreased the crystallinity of the aluminosilicate framework and the ..cap alpha..-AgI reflections in the x-ray patterns were enhanced. Mild ..gamma.. irradiations (approx. 50 MR) affected the x-ray diffraction patterns of some of the zeolites. Various lead oxyhalides had very poor thermal stability.
- Research Organization:
- Rockwell International Corp., Canoga Park, CA (United States). Energy Systems Group; Pennsylvania State Univ., University Park (USA). Materials Research Lab.
- DOE Contract Number:
- AC09-79ET41900
- OSTI ID:
- 6354429
- Report Number(s):
- DOE/ET/41900-9; ESG-DOE-13354; ON: DE81026067; TRN: 81-014946
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
IODINE 129
LEACHING
MINERALS
RADIATION EFFECTS
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE PROCESSING
SINTERING
SOLIDIFICATION
ZEOLITES
ALUMINIUM SILICATES
BORATES
CERAMICS
IODIDES
MAGNESIUM COMPOUNDS
SILVER COMPOUNDS
SODIUM SILICATES
VERY HIGH TEMPERATURE
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BORON COMPOUNDS
DISSOLUTION
FABRICATION
HALIDES
HALOGEN COMPOUNDS
INORGANIC ION EXCHANGERS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE COMPOUNDS
IODINE ISOTOPES
ION EXCHANGE MATERIALS
ISOTOPES
MANAGEMENT
MATERIALS
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PROCESSING
RADIOISOTOPES
SEPARATION PROCESSES
SILICATES
SILICON COMPOUNDS
SODIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTE PROCESSING
YEARS LIVING RADIOISOTOPES
052001* - Nuclear Fuels- Waste Processing
052002 - Nuclear Fuels- Waste Disposal & Storage
360605 - Materials- Radiation Effects
360206 - Ceramics
Cermets
& Refractories- Radiation Effects