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Title: Instability of U3Si2 in pressurized water media at elevated temperatures

Journal Article · · Communications Chemistry

Following the Fukushima Daiichi accident, significant efforts from industry and the scientific community have been directed towards the development of alternative nuclear reactor fuels with enhanced accident tolerance. Among the proposed materials for such fuels is a uranium silicide compound (U3Si2), which has been selected for its enhanced thermal conductivity and high density of uranium compared to the reference commercial light water reactor (LWR) nuclear fuel, uranium oxide (UO2). To be a viable candidate LWR fuel, however, U3Si2 must also demonstrate that, in the event of this fuel coming in contact with aqueous media, it will not degrade rapidly. In this contribution, we report the results of experiments investigating the stability of U3Si2 in pressurized water at elevated temperatures and identify the mechanisms that control the interaction of U3Si2 under these conditions. Our data indicate that the stability of this material is primarily controlled by the formation of a layer of USiO4 (the mineral, coffinite) at the surface of U3Si2. The results also show that these layers are destabilized at T > 300 °C, leading to the complete decomposition of U3Si2 and its pulverization due to its full oxidation to UO2.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE; USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
Grant/Contract Number:
89233218CNA000001; AC05-00OR22725
OSTI ID:
1797894
Report Number(s):
LA-UR--20-27557
Journal Information:
Communications Chemistry, Journal Name: Communications Chemistry Journal Issue: 1 Vol. 4; ISSN 2399-3669
Publisher:
Springer NatureCopyright Statement
Country of Publication:
United States
Language:
English

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