Title

Diffusional Interaction Between U-10 wt pct Zr and Fe at 903 K, 923 K, and 953 K (630 A degrees C, 650 A degrees C, and 680 A degrees C)

Authors

Authors

Y. Park; K. Huang; A. P. Y. Puente; H. S. Lee; B. H. Sencer; J. R. Kennedy;Y. H. Sohn

Comments

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Abbreviated Journal Title

Metall. Mater. Trans. A-Phys. Metall. Mater. Sci.

Keywords

U-ZR; METALLIC FUELS; URANIUM; INTERDIFFUSION; REACTORS; BEHAVIOR; ALLOYS; IRON; Materials Science, Multidisciplinary; Metallurgy & Metallurgical; Engineering

Abstract

U-Zr metallic fuels cladded in Fe-alloys are being considered for application in an advanced sodium-cooled fast reactor 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 fuels with Fe-alloys, a systematic multicomponent diffusion study was carried out using solid-to-solid diffusion couples. The U-10 wt pct Zr vs pure Fe diffusion couples were assembled and annealed at temperatures, 903 K, 923 K, and 953 K (630 A degrees C, 650 A degrees C, and 680 A degrees C) 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, alpha-U, beta-U, Zr-precipitates, chi, epsilon, and lambda 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 electron diffraction analyses were carried out to determine, for the first time, the exact crystal structure and composition of chi, epsilon, and lambda-phases. The chi, epsilon, and lambda-phases were identified as Pnma(62) Fe(Zr,U), I4/mcm(140) Fe(Zr,U)(2), and P42/mnm(136) U-3(Zr,Fe), respectively.

Journal Title

Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science

Volume

46A

Issue/Number

1

Publication Date

1-1-2015

Document Type

Article

Language

English

First Page

72

Last Page

82

WOS Identifier

WOS:000346788600013

ISSN

1073-5623

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