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Title: Diffusional Interaction between U-10 wt.% Zr and Fe at 903K, 923K and 953K (630°C, 650°C, and 680°C)

U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced Sodium-Cooled Fast Reactor (SFR) that can recycle the U-Zr fuels and minimize the long-lived actinide waste. To understand the complex fuel-cladding chemical interaction between the U-Zr metallic fuel with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt.% Zr vs. pure Fe diffusion couples were assembled and annealed at temperatures, 903, 923 and 953K for 96 hours. Development of microstructure, phase constituents, and compositions developed during the thermal anneals were examined by scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy. Complex microstructure consisting of several layers that include phases such as U6Fe, UFe2, ZrFe2, α-U, β-U, Zr-precipitates, Χ, ε and λ were observed. Multi-phase layers were grouped based on phase constituents and microstructure, and the layer thicknesses were measured to calculate the growth constant and activation energy. The local average compositions through the interaction layer were systematically determined, and employed to construct semi-quantitative diffusion paths on isothermal U-Zr-Fe ternary phase diagrams at respective temperatures. The diffusion paths were examined to qualitatively estimate the diffusional behavior of individual components and their interactions. Furthermore, selected area diffraction analysesmore » were carried out to determine, for the first time, the exact crystal structure and composition of Χ, ε and λ-phases. The Χ, ε and λ-phases were identified as Pnma(62) Fe(Zr,U), I4/mcm(140) Fe(Zr,U)2, and I4/mcm(140) U3(Zr,Fe), respectively.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [4]
  1. Univ. of Central Florida, Orlando, FL (United States). Advanced Materials Processing and Analysis Ctr.
  2. Northwestern Univ., Evanston, IL (United States)
  3. Kyungpook National Univl, Daegu (Korea, Republic of)
  4. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Publication Date:
OSTI Identifier:
1177615
Report Number(s):
INL/JOU--13-29741
Journal ID: ISSN 1073-5623; TRN: US1500052
DOE Contract Number:
DE-AC07-05ID14517
Resource Type:
Journal Article
Resource Relation:
Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science; Journal Volume: 46; Journal Issue: 1
Publisher:
ASM International
Research Org:
Idaho National Laboratory (INL), Idaho Falls, ID (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; TETRAGONAL LATTICES; ORTHORHOMBIC LATTICES; DIFFUSION; FUEL-CLADDING INTERACTIONS; Ternary Alloy Systems; Temperature Range 0400-1000 K; SCANNING ELECTRON MICROSCOPY; Fast Reactors; SODIUM COOLED REACTORS; Reprocessing; Radioactive Waste Management; Minimization; Chemical Composition; Crystal Structure; Space Groups; TRANSMISSION ELECTRON MICROSCOPY; ALLOY NUCLEAR FUELS; PHASE DIAGRAMS; X RADIATION; CLADDING; ELECTRON DIFFRACTION; MICROSTRUCTURE; ACTIVATION ENERGY; IRON ALLOYS; ANNEALING; LAYERS; PRECIPITATION; SOLIDS; THICKNESS; X-RAY SPECTROSCOPY; Experimental Data Fuel-Cladding Chemical Interactions; Interdiffusion; Transmission Electron Microscopy