Abstract
U3Si2 is a candidate fissile phase for use in accident tolerant fuel systems because of its higher fissile density, higher thermal conductivity when compared to uranium dioxide. It is also expected to have acceptable performance in contact with high temperature water (e.g., a leaker event from breached cladding) and in regards to interaction with different cladding materials. In high temperature water, U3Si2 is expected to form a protective SiO2 coating. However, the resistance of U3Si2 to corrosion under light water reactor service conditions has been previously unknown. In this study, the corrosion tests of sintered U3Si2 discs were conducted in pressurized water at 300°C in an autoclave. The exposure times to corrosion were 6 hours and 24 hours. Detailed composition and microstructural analysis were carried out using a combination of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) equipped with energy dispersive X-ray spectroscopy (EDS). Only slight weight change of U3Si2 discs can be detected in corrosion tests up to 24 hours. A layered structure of corrosion products formed on U3Si2, with a glassy silicon oxide layer at the top followed by a nanocrystalline UO2 layer, a Sirich oxide layer and then a mixture oxide layer of U and Si. A diffusion couple of U3Si2 in contact with Zircaloy-4 has been tested at 800°C up to 100 hours. The resulting microstructure and interdiffusion has been studied with SEM/EDS. Some limited interdiffusion has been observed in these tests, and a layer containing Zr and Si forms between the U3Si2 disc and the Zircaloy-4 disc.
Original language | English |
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Title of host publication | Top Fuel 2016 |
Subtitle of host publication | LWR Fuels with Enhanced Safety and Performance |
Publisher | American Nuclear Society |
Pages | 1341-1346 |
Number of pages | 6 |
ISBN (Electronic) | 9780894487309 |
State | Published - 2016 |
Externally published | Yes |
Event | Top Fuel 2016: LWR Fuels with Enhanced Safety and Performance - Boise, United States Duration: Sep 11 2016 → Sep 15 2016 |
Publication series
Name | Top Fuel 2016: LWR Fuels with Enhanced Safety and Performance |
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Conference
Conference | Top Fuel 2016: LWR Fuels with Enhanced Safety and Performance |
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Country/Territory | United States |
City | Boise |
Period | 09/11/16 → 09/15/16 |
Funding
This work was supported by the U.S. Department of Energy, Office of Nuclear Energy. This work is also part an collaboration lead by Westinghouse Electric Company comprising several national laboratories, vendors, and universities awarded in response to the DE-FOA-0000712 funding opportunity.
Keywords
- Accident tolerant fuels
- Corrosion
- Diffusion