DISSOLUTION OF POWER REACTOR FUEL CORES

Technical Report · Fri Aug 26 04:00:00 EDT 1960

OSTI ID:4837791

Blaine, H T

Molybdenum alloys of uranium are difficult to dissolve in nitric acid. At low acid concentrations, the molybdenum precipitates, carrying down significant amounts of uranium. However, the addition of ferric nitrate to low acid solutions prevents the precipitation of molybdenum. Also, above 13 M acid the molybdenum precipitate contains little uranium allowing the supernate to be processed in a conventional manner for uranium-plutonium recovery. The dissolution rate of uranium-3% molybdenum alloy is proportional to the second power of the nitrate ion concentration in the absence of ferric ion and to the third power of the nitrate concentration in the presence of ferric ion. Typical rates with ferric ion were 42 mils per hour at 3.9 M nitrate and 104 mils per hour at 6.0 M nitrate. Uranyl ion suppresses the dissolution rate of alloy. With 1.0 M uranyl nitrate, the dissolution rate is about one third the predicted rate. Uranium 3% molybdenum alloy dissolved in nitric acid-ferric nitrate solutions with the stoichiometry: U + 4.2HNO/sub 3/ + 0.95O/sub 2/ UO/sub 2/(NO/ sub 3/)/sub 2/ + 2.2NO/sub 2/ + 2.1 H/sub 2/O + 230 kcal. Uranium dissolve s in nitric acid at a rate proportional to the 2.7 power of the nitrate ion concentration. The rates range from 1.7 mils per hour at 4.4 M nitrate to 35 mils per hour at 13 M nitrate. Uranium dissolves in nitric acid-uranyl nitrate solutions with the stoichiometry: U + 4HNO/sub 3/ + O/sub 2/ UO/sub 2/(NO/sub 3/)/ sub 2/ + 2NO/sub 2/ + 2H/sub 2/O + 264 kcal. The dissolution rate of uranium dioxide 92% theoretical density sintered pellets is proportional to the 1.2 power of the nitric acid concentration and ranges from 6 mils per hour at 0.6 M acid to 70 mils per hour at 5.5 M acid. Uranium dioxide dissolves in nitric acid with the stoichiometry: UO/sub 2/ + 3HNO/sub 3/ + 0.25O/sub 2/ UO/sub 2/(NO/sub 3/)/ sub 2/ + NO/sub 2/ + 1.5H/sub 2/O + 17.2 kcal. The dissolution rat es of the four core materials are the same for recirculating and batch dissolvers. (auth)

• Research Organization: General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
• DOE Contract Number: AT(45-1)-1350
• NSA Number: NSA-15-032229
• OSTI ID: 4837791
• Report Number(s): HW-66320
• Country of Publication: United States
• Language: English

Related Subjects

CHEMISTRY
FUELS
IONS
IRON NITRATES
MOLYBDENUM ALLOYS
NITRIC ACID
PELLETS
PLUTONIUM
PRECIPITATION
PREPARATION
REACTOR CORE
RECOVERY
SINTERING
SOLUTIONS
URANIUM
URANIUM ALLOYS
URANIUM DIOXIDE
URANYL COMPOUNDS
URANYL NITRATES