Pellet fabrication development using thermally denitrated UO{sub 2} powder

Technical Report · Fri May 01 04:00:00 EDT 1992

DOI:https://doi.org/10.2172/10144382· OSTI ID:10144382

Davis, N C; Griffin, C W

Pacific Northwest Laboratory (PNL) has evaluted, on a laboratory scale, the characteristics and pellet fabrication properties of UO{sub 3} powder prepared by the thermal denitration process. Excellent quality, 96% TD (percent of theoretical density) pellets were produced from development lots of this powder. Apparently, the key to making this highly sinterable powder from uranyl nitrate is the addition of ammonium nitrate (NH{sub 4}NO{sub 3}) to the feed solution prior to thermal denitration. Powder lots were processed with and without the NH{sub 4}NO{sub 3} addition in the feed solution. The lots included samples from the ORNL laboratory rotary kiln and from a larger scale rotary kiln at National Lead of Ohio (NLO). In the PNL evaluation, samples of UO{sub 3} were calculated and reduced to UO{sub 2}, followed by conventional process procedures to compare the sinterability of the powder lots. The high density pellets made from the powder lots, which included the NH{sub 4}NO{sub 3} addition, were reduced to Fast Breeder Reactor (FBR) density range of 88 to 92% TD by the use of poreformers. The NH{sub 4}NO{sub 3} addition also improved the sinterability properties of uranium oxide powders that contain thorium and cerium. Thorium and cerium were used as ``stand-in`` for plutonium used in urania-plutonia FBR fuel pellets. A very preliminary examination of a single lot of thermally denitrated uranium-plutonium oxide powder was made. This powder lot was made with the NH{sub 3}NO{sub 3} addition and produced pellets just above the FBR density range.

• Research Organization: Pacific Northwest Lab., Richland, WA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 10144382
• Report Number(s): PNL--4305; ON: DE92014058
• Country of Publication: United States
• Language: English

Related Subjects

050700
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210500
AMMONIUM NITRATES
CALCINATION
CERIUM
DENITRATION
DENSITY
FABRICATION
FUEL PELLETS
FUELS PRODUCTION AND PROPERTIES
KILNS
LMFBR TYPE REACTORS
PLUTONIUM OXIDES
POWDERS
POWER REACTORS
BREEDING
SINTERING
THORIUM
URANIUM TRIOXIDE
URANYL NITRATES