Phase decomposition and bubble evolution in Xe implanted U₃Si₂ at 450°C

Journal Article · Thu Feb 07 00:00:00 EST 2019 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2019.02.004· OSTI ID:1530396

Miao, Yinbin ^[1]; Harp, Jason  ^[2]; Mo, Kun ^[1]; Mei, Zhi-Gang ^[1]; Xu, Ruqing ^[1]; Zhu, Shaofei ^[1]; Yacout, Abdellatif M. ^[1]

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1. Argonne National Lab. (ANL), Lemont, IL (United States)
2. Idaho National Lab. (INL), Idaho Falls, ID (United States)

We report on the microstructure investigations of a U₃Si₂ specimen implanted by 84 MeV Xe ions at 450°C. In the region that corresponds to the highest irradiation dose, U₃Si₂ was found to decompose into a Si-enriched nanocrystalline USi matrix phase and a U-enriched amorphous inclusion phase. Density functional theory (DFT) calculations were used to help understand the decomposition mechanism. Xe bubbles of different morphologies were observed in USi nano-grains, on USi grain boundaries, and phase boundaries. Original U₃Si₂ micro-grains were preserved on both sides of the irradiation damage peak region within the sample, implying a radiation dose threshold for decomposition of approximately 150 dpa at 450°C. In the preserved U₃Si₂ region beneath the irradiation damage peak, where critical amount of Xe ions were deposited, a monomodal size distribution of intragranular Xe bubbles with an average size of 2.68 nm formed. In both decomposed and preserved U₃Si₂, the size of Xe bubbles was found to be lower than 50 nm. Based on this observation, the fission gas behavior of U₃Si₂ is controllable and free of run-away swelling despite the occurrence of decomposition at this irradiation temperature. (C) 2019 Elsevier B.V. All rights reserved.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE); USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: AC02-06CH11357; AC07-051D14517; FOA-0001063
• OSTI ID: 1530396
• Alternate ID(s): OSTI ID: 1636089
• Journal Information: Journal of Nuclear Materials, Vol. 518, Issue C; ISSN 0022-3115
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
36 MATERIALS SCIENCE
U3Si2
accident tolerant fuel
fission gas behavior
ion irradiation
light water reactor (LWR)
microstructure characterization