DISSOLUTION OF BeO-AND Al$sub 2$$O$$sub 3$-BASE REACTOR FUEL ELEMENTS. PART I

Technical Report · Wed Feb 14 00:00:00 EST 1962

DOI:https://doi.org/10.2172/4809878· OSTI ID:4809878

Warren, K S; Ferris, L M; Kibbey, A H

Aqueous methods for recovering uranium from BeO- and Al/sub 2/O/sub 3/- base gas-cooled-reactor fuel elements are being evaluated. Two methods for processing Hastelloy-X--clad pelletized BeO-base fuels containing 60 to 70% UO/ sub 2/, such as the GCRE and MGCR, seem feasible. One method involves mechanical stripping or chopping of the cladding followed by leaching of the uranium from the fuel pellets with boiling 6-l3M HNO/sub 3/. In the other method the cladding and UO/sub 2/ are dissolved in boiling 2M HNO/sub 3/-4M HCl. In either case, most of the BeO matrix remains as an undissolved residue. Pellets containing 70% UO/sub 3/ dissolved completely in less than 20 hr in boiling 8M HNO/sub 3/ containing either 2M H/sub 2/SO/sub 4/ or 0.5M HF, producing solutions containing 4 g of uranium per liter. Fuels of high BeO content, e.g. BeO--5% UO/sub 2/, dissolved only slowly in boiling aqueous reagents. Highest initial rates were in sulfuric acid solutions, log (Rate, mg min/sup -1/cm/sup -2/) = 0.223 (H/sub 2/SO/ sub 4, M) - 2.8l and in HF--NH/sub 4/F solutions. ln boiling 5-8M NH/sub 4/F the initial dissolution rate increased from 0.07 to 3.5 mg min/sup -1/cm/sup -2/ as the HF concentration increased from 0 to 20M. Leaching, with boiling l0M HNO/sub 3/, of uranium from UO/sub 2/--Al/sub 2/O/sub 3/ fuel pellets was studied briefly. In 4 hr leaching uranium recoveries from pellets containing l0- mu grains of UO/ sub 2/ dispersed in an Al/sub 2/O/sub 3/ matrix decreased from 99.99 to 11.6% when the Al/sub 2/O/sub 3/content of the pellets increased from 3.7 to 61.1%. The uranium concentration was l.0M in the case of complete dissolution. (auth)

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-16-010101
• OSTI ID: 4809878
• Report Number(s): ORNL-3220(Pt.I)
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-62
• Country of Publication: United States
• Language: English

Related Subjects

CHEMISTRY
ALUMINUM OXIDES
AMMONIUM COMPOUNDS
BERYLLIUM OXIDES
BOILING
CANNING
COATING
COOLING
FUEL ELEMENTS
HYDROCHLORIC ACID
HYDROFLUORIC ACID
HYDROXIDES
LEACHING
NITRIC ACID
PELLETS
PLATING
REACTORS
RECOVERY
REPORT
REPROCESSING
SEPARATION PROCESSES
SOLUTIONS
SOLVENT EXTRACTION
SULFURIC ACID
URANIUM DIOXIDE