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Title: Synthesis of phase-pure U 2N 3 microspheres and its decomposition into UN

Uranium mononitride (UN) is important as a nuclear fuel. Fabrication of UN in its microspherical form also has its own merits since the advent of the concept of accident-tolerant fuel, where UN is being considered as a potential fuel in the form of TRISO particles. But, not many processes have been well established to synthesize kernels of UN. Therefore, a process for synthesis of microspherical UN with a minimum amount of carbon is discussed herein. First, a series of single-phased microspheres of uranium sesquinitride (U 2N 3) were synthesized by nitridation of UO 2+C microspheres at a few different temperatures. Resulting microspheres were of low-density U 2N 3 and decomposed into low-density UN. The variation of density of the synthesized sesquinitrides as a function of its chemical composition indicated the presence of extra (interstitial) nitrogen atoms corresponding to its hyperstoichiometry, which is normally indicated as α-U 2N 3. Average grain sizes of both U 2N 3 and UN varied in a range of 1–2.5 μm. In addition, these had a considerably large amount of pore spacing, indicating the potential sinterability of UN toward its use as a nuclear fuel.
Authors:
 [1] ;  [1] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 54; Journal Issue: 1; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; uranium nitride kernels; uranium sesquinitride; uranium mononitride
OSTI Identifier:
1265341

Silva, Chinthaka M., Hunt, Rodney Dale, Snead, Lance Lewis, and Terrani, Kurt A.. Synthesis of phase-pure U2N3 microspheres and its decomposition into UN. United States: N. p., Web. doi:10.1021/ic502457n.
Silva, Chinthaka M., Hunt, Rodney Dale, Snead, Lance Lewis, & Terrani, Kurt A.. Synthesis of phase-pure U2N3 microspheres and its decomposition into UN. United States. doi:10.1021/ic502457n.
Silva, Chinthaka M., Hunt, Rodney Dale, Snead, Lance Lewis, and Terrani, Kurt A.. 2014. "Synthesis of phase-pure U2N3 microspheres and its decomposition into UN". United States. doi:10.1021/ic502457n. https://www.osti.gov/servlets/purl/1265341.
@article{osti_1265341,
title = {Synthesis of phase-pure U2N3 microspheres and its decomposition into UN},
author = {Silva, Chinthaka M. and Hunt, Rodney Dale and Snead, Lance Lewis and Terrani, Kurt A.},
abstractNote = {Uranium mononitride (UN) is important as a nuclear fuel. Fabrication of UN in its microspherical form also has its own merits since the advent of the concept of accident-tolerant fuel, where UN is being considered as a potential fuel in the form of TRISO particles. But, not many processes have been well established to synthesize kernels of UN. Therefore, a process for synthesis of microspherical UN with a minimum amount of carbon is discussed herein. First, a series of single-phased microspheres of uranium sesquinitride (U2N3) were synthesized by nitridation of UO2+C microspheres at a few different temperatures. Resulting microspheres were of low-density U2N3 and decomposed into low-density UN. The variation of density of the synthesized sesquinitrides as a function of its chemical composition indicated the presence of extra (interstitial) nitrogen atoms corresponding to its hyperstoichiometry, which is normally indicated as α-U2N3. Average grain sizes of both U2N3 and UN varied in a range of 1–2.5 μm. In addition, these had a considerably large amount of pore spacing, indicating the potential sinterability of UN toward its use as a nuclear fuel.},
doi = {10.1021/ic502457n},
journal = {Inorganic Chemistry},
number = 1,
volume = 54,
place = {United States},
year = {2014},
month = {12}
}