Identification of secondary phases formed during unsaturated reaction of UO{sub 2} with EJ-13 water

Conference · Mon Dec 31 04:00:00 EST 1990

OSTI ID:138170

Bates, J K; Tani, B S; Veleckis, E; Wronkiewicz, D J ^[1]

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1. Argonne National Lab., IL (USA)

A set of experiments, wherein UO{sub 2} has been contacted by dripping water, has been conducted over a period of 182.5 weeks. The experiments are being conducted to develop procedures to study spent fuel reaction under unsaturated conditions that are expected to exist over the lifetime of the proposed Yucca Mountain repository site. One half of the experiments have been terminated, while one half are ongoing. Analyses of solutions that have dripped from the reacted UO{sub 2} have been performed for all experiments, while reacted UO{sub 2} surfaces have been examined for the terminated experiments. A pulse of uranium release from the UO{sub 2} solid, combined with the formation of schoepite on the surface of the UO{sub 2}, was observed between 39 and 96 weeks of reaction. Thereafter, the uranium release decreased and a second set of secondary phases was observed. The latter phases incorporated cations from the EJ-13 water and include boltwoodite, uranophane, sklodowskite, compreignacite, and schoepite. The experiments are continuing to monitor whether additional changes in solution chemistry or secondary phase formation occurs.

• Research Organization: Materials Research Society, Pittsburgh, PA (United States)
• OSTI ID: 138170
• Report Number(s): CONF-891129--
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
BOLTWOODITE
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
COMPREIGNACITE
DROPLETS
HIGH-LEVEL RADIOACTIVE WASTES
LEACHING
MOISTURE
RADIOACTIVE WASTE DISPOSAL
RADIONUCLIDE MIGRATION
SCHOEPITE
SITE CHARACTERIZATION
SKLODOWSKITE
SPENT FUELS
SURFACE AREA
TUFF
URANIUM DIOXIDE
URANOPHANE
VOLUME
WATER SATURATION
YUCCA MOUNTAIN
Yucca Mountain Project