Immobilization of krypton-85 in zeolite 5A and porous glass
This report demonstrates the technical and economic feasibility for immobilizing krypton-85 by high pressure/high temperature encapsulation in zeolite 5A or thirsty Vyco porous glass. Data are presented to show how process conditions affect the encapsulation and how to compact the zeolite beads with glass frit or other additives to form a fused mass with low dispersibility potential. Krypton specific loadings of 30 and 50 m/sup 3/ STP gas per m/sup 3/ solid are readily achieved at 100 MPa in porous glass at 900/sup 0/C and zeolite 5A at 700/sup 0/C. Krypton is encapsulated by a sintering process where the porous glass and zeolite 5A voids are sealed. With zeolite 5A, the initial water concentration has a catalytic effect on the sintering, resulting in a transition from crystalline zeolite 5A to an amorphous aluminosilicate. Krypton leakage experiments are used to predict leakage rates from glass or zeolite of less than 0.03% and 0.3% for 10-y storage at 300 and 400/sup 0/C, respectively. Heating the loaded zeolite at 600 to 700/sup 0/C for 4 h removes 0.1% of the total krypton which is loosely held and reduces the subsequent leakage rates at 300 to 400/sup 0/C. Zeolite 5A is chosen as the preferred material to immobilize krypton-85. A preconceptual design and cost estimate is given for a facility to encapsulate 110% of the krypton production of a 2000 metric ton of heavy metal per year reprocessing plant, or 230 m/sup 3/ of gas containing 19 MCi of krypton-85. A hot isostatic press (HIP) with an isolated work zone of 8 or 16 L capacity is required to operate for 600 or 300 cycles per year, respectively. Existing HIP technology uses work zones from 1 to 3500 L capacity at similar production rates. A preliminary safety evaluation shows that an incredible worst case accident could be contained and the maximum off-site dose would be well below accident protective action guidance levels.
- Research Organization:
- Exxon Nuclear Idaho Co., Inc., Idaho Falls (USA)
- DOE Contract Number:
- AC07-79ID01675
- OSTI ID:
- 5258470
- Report Number(s):
- ENICO-1102; ON: DE82011257; TRN: 82-012925
- Resource Relation:
- Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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Preliminary safety evaluation of a commercial-scale krypton-85 encapsulation facility
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11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
FUEL REPROCESSING PLANTS
OFF-GAS SYSTEMS
KRYPTON 85
ENCAPSULATION
COST
DESIGN BASIS ACCIDENTS
FEASIBILITY STUDIES
HEATING
LEAKS
POROUS MATERIALS
RADIATION DOSES
SAFETY
VYCOR
ZEOLITES
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BETA DECAY RADIOISOTOPES
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EVEN-ODD NUCLEI
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INORGANIC ION EXCHANGERS
INTERMEDIATE MASS NUCLEI
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ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KRYPTON ISOTOPES
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MINERALS
NUCLEAR FACILITIES
NUCLEI
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YEARS LIVING RADIOISOTOPES
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