Preliminary Results of Voloxidation Processing of Kilogram Quantities of Used Nuclear Fuel
- ORNL
Advanced nuclear fuel processing methodologies are being studied as part of the Advanced Fuel Cycle Initiative (AFCI) program at ORNL. To support this initiative, processes and equipment were deployed at ORNL to perform all steps in the recycle process on actual used nuclear fuels, ranging from used fuel receipt to production of products and waste forms at the kilogram-scale (with capacity to process 20 kg of used fuel per year in up to four campaigns). In the first campaign, approximately 4 kg of used fuel was processed. As previously reported, the head-end processing was completed using saw-segmented Dresden fuel in lab-scale equipment in multiple batches. The second processing campaign used a new single pin shear and a new bench-scale voloxidizer to perform the dry head-end treatment prior to fuel dissolution. Approximately ~5 kg of used fuel (heavy metal basis) was processed in the second campaign. Two different fuels were oxidized in three separate batches to provide a range of processing conditions. The material used for each batch and general processing conditions are summarized in Table 1. Progress of the oxidation reaction was monitored continuously by two primary measurements; the concentration of oxygen in the effluent stream which was depressed as the oxygen was consumed, and the concentration of krypton-85 in the effluent stream as measured by a gamma counter on the off-gas pipeline. Table 1. Voloxidation test conditions for second campaign. Batch Fuel Source Burnup (GWd/MT)Batch size (kg*)/(kg**)Segment Length (in) Oxidation GasOperation Temperature ( C) 1Surry-2361.223/1.7041.0Air500 2North Anna63 702.071/2.8850.88Air600 3North Anna63 702.012/2.8030.88Oxygen600 * Heavy metal basis. ** Total fuel (oxide + cladding) basis. Fission product gases evolved from the fuel during the oxidation process were trapped for subsequent chemical and radiochemical analysis. The series of traps included a bed of molecular sieves to recover tritium (as HTO), silver-substituted zeolite to capture iodine (e.g. as AgI), a caustic scrubber to collect carbon dioxide (including 14CO2), a hydrogen-substituted mordenite to capture krypton (e.g. 85Kr) by cryogenic temperature swing adsorption, and a silver-substituted mordenite to capture xenon by cryogenic temperature swing absorption. The quantities of these volatile gases collected were compared to ORIGEN calculations to estimate the effectiveness of the voloxidation process to separate the volatiles from the used fuel. This paper will describe the voloxidation system and present preliminary results from the second processing campaign.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 963919
- Resource Relation:
- Conference: 33rd Annual Actinide Separations Conference, Tahoe City, CA, USA, 20090518, 20090521
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
ACTINIDES
CARBON DIOXIDE
FISSION PRODUCTS
FUEL CYCLE
HEAVY METALS
KRYPTON 85
MOLECULAR SIEVES
MORDENITE
NUCLEAR FUELS
OXIDATION
OXYGEN
PROCESSING
RADIOCHEMICAL ANALYSIS
VOLOXIDATION PROCESS
WASTE FORMS