Constituent redistribution modeling in U-Zr fast reactor fuel

Journal Article · Sat Dec 31 04:00:00 EST 1994 · Transactions of the American Nuclear Society

OSTI ID:89085

Hayes, S L ^[1]; Hofman, G L ^[2]

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

Constituent redistribution in U-Zr metallic fuel is observed at elevated fuel operating temperatures. The restructured fuel is typically characterized by a three-zone radial structure. This structure consists of an outermost zone that extends from the fuel surface radially inward and retains the as-fabricated composition, an innermost zone that extends from the fuel center radially outward and is enriched in zirconium above the as-fabricated level and an intermediate zone that is depleted in zirconium. These three zones have been shown to be consistent with three distinct phase fields within the miscibility gap on the uranium-rich side of the U-Zr phase diagram: the outermost zone that retains the as-fabricated composition is composed of the two-phase mixture {alpha} + {gamma}{sub 2}, the zirconium-depleted intermediate zone of {beta} + {gamma}{sub 2}, and the zirconium-enriched innermost zone of {gamma}{sub 1} + {gamma}{sub 2} or pure {gamma}. Experimental evidence suggests that the zirconium enrichment of the {gamma} zone occurs rapidly prior to reaching a zirconium content corresponding to the triple-point at {approximately}42 at.% Zr but proceeds above this zirconium level more slowly. The process is assumed to be a thermotransport phenomenon due to the radial fuel thermal gradient, with the thermodynamics of the {gamma}-U phase controlling the process. Modeling efforts by Ogawa et al. and Ishida. et al. have yielded results that are inconsistent with experimental observations. This paper presents a redistribution model that is more consistent with experimental results.

• OSTI ID: 89085
• Report Number(s): CONF-941102--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 71; ISSN 0003-018X; ISSN TANSAO
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
ALLOY NUCLEAR FUELS
DIFFUSION
FAST REACTORS
IRRADIATION
MATHEMATICAL MODELS
PHASE TRANSFORMATIONS
TRANSITION HEAT
URANIUM ALLOYS
ZIRCONIUM ALLOYS