Dissolution of COPRECAL mixed-oxide fuel
Conclusions based on this investigation of continuous coprecipitation-calcination (COPRECAL) mixed oxide (MOX) dissolution are as follows: (1) A large fraction of the COPRECAL MOX dissolved very rapidly in nitric acid alone. Appeoximately 95% of the powder tested dissolved in the first 5 to 6 minutes in boiling 8 to 12M nitric acid. The remainder dissolved much more slowly, with greater than 99% dissolved after 8 hours. The dissolution rate increased slightly as the nitric concentration was increased from 8 to 12M. (2) Of the fuel fabrication operations investigated, only the sintering operation had a significant effect on the dissolution rate. In tests with samples from a fuel fabrication run, the sintered pellet samples had approximately one-tenth as much residue remaining at the end of 6- and 12-hour tests in 12M nitric acid compared to the MOX powder starting material. (3) The presence of Pu and U in the nitric acid dissolvent had very little effect on the dissolution rate. In tests with Pu-U nitrate-nitric acid solution as the dissolvent, the final 5% of the COPRECAL sample dissolved slightly slower than it had in tests with nitric acid only as the dissolvent. (4) The plutonium-uranium ratio was higher in the final residue than in the starting material. At the end of a 6-hour dissolution test in 10M nitric acid the Pu-U ratio in the residue was 4 vs 0.25 in the starting material. (5) A final residue of undissolved oxide can be expected in the Wet Scrap Development Laboratory (WSDL) dissolver. As a way to minimize the buildup of undissolved MOX powder in the continuous dissolver, all scrap material could be subjected to high temperature sintering (e.g., approx. 1700/sup 0/C) prior to processing through WSDL.
- Research Organization:
- Hanford Engineering Development Lab., Richland, WA (USA)
- DOE Contract Number:
- AC14-76FF02170
- OSTI ID:
- 6076060
- Report Number(s):
- HEDL-SA-2327; CONF-810606-93; ON: DE81028205
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
050800* -- Nuclear Fuels-- Spent Fuels Reprocessing
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
ACTINIDE COMPOUNDS
CALCINATION
CHALCOGENIDES
CHEMICAL REACTIONS
COPRECIPITATION
DECOMPOSITION
DISSOLUTION
ENERGY SOURCES
FABRICATION
FUELS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MATERIALS
MIXED OXIDE FUELS
NITRIC ACID
NUCLEAR FUELS
OXIDES
OXYGEN COMPOUNDS
PLUTONIUM COMPOUNDS
PLUTONIUM OXIDES
PRECIPITATION
PYROLYSIS
REACTOR MATERIALS
REPROCESSING
SEPARATION PROCESSES
SOLID FUELS
SPENT FUELS
THERMOCHEMICAL PROCESSES
TRANSURANIUM COMPOUNDS
URANIUM COMPOUNDS
URANIUM OXIDES