Magnetic resonance as a structural probe of a uranium (VI) sol-gel process

Conference · Sun Dec 31 04:00:00 EST 1989

OSTI ID:10164513

King, C M; Thompson, M C; Buchanan, B R ^[1]; King, R B ^[2]; Garber, A R ^[3]

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1. Westinghouse Savannah River Co., Aiken, SC (United States)
2. Georgia Univ., Athens, GA (United States). Dept. of Chemistry
3. South Carolina Univ., Columbia, SC (United States). Dept. of Chemistry

NMR investigations on the ORNL process for sol-gel synthesis of microspherical nuclear fuel (UO{sub 2}), has been useful in sorting out the chemical mechanism in the sol-gel steps. {sup 13}C, {sup 15}N, and {sup 1}H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C{sub 6}H{sub l2}N{sub 4}) has revealed near quantitative stability of this adamantane-like compound in the sol-Gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. {sub 17}0 NMR of uranyl (UO{sub 2}{sup ++}) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, [(UO{sub 2}){sub 3}({mu}{sub 3}-O)({mu}{sub 2}-OH){sub 3}]{sup +}, induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results show that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH{sup +} is occluded as an ``intercalation`` cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH{sub 4}){sub 2}[(UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}] {center_dot} 8H{sub 2}0. This compound is the precursor to sintered U0{sub 2} ceramic fuel.

• Research Organization: Westinghouse Savannah River Co., Aiken, SC (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC09-89SR18035
• OSTI ID: 10164513
• Report Number(s): WSRC-RP--89-1285; CONF-900466--107; ON: DE92017909
• Country of Publication: United States
• Language: English

Related Subjects

050700
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
36 MATERIALS SCIENCE
360201
665100
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMINES
AMMONIUM URANATES
CARBON 13
CHEMICAL REACTION KINETICS
FUELS PRODUCTION AND PROPERTIES
HYDROGEN
HYDROLYSIS
MICROSPHERES
NITROGEN 15
NUCLEAR MAGNETIC RESONANCE
NUCLEAR TECHNIQUES IN CONDENSED MATTER PHYSICS
OXYGEN 17
PREPARATION AND FABRICATION
SOL-GEL PROCESS
SYNTHESIS
URANIUM DIOXIDE
URANYL COMPOUNDS
URANYL NITRATES