U-10Mo/Zr Interface Modeling using a Microstructure-Based FEM Approach

Technical Report · Mon Apr 25 00:00:00 EDT 2016

DOI:https://doi.org/10.2172/1339915· OSTI ID:1339915

Soulami, Ayoub ^[1]; Xu, Zhijie ^[1]; Joshi, Vineet V. ^[1]; Burkes, Douglas ^[1]; Lavender, Curt A. ^[1]; McGarrah, Eric J. ^[1]

---

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

The U-10Mo in low enrichments (LEU) has been identified as the most promising alternative to the current highly enriched uranium (HEU) used in the United States’ fleet of high performance research reactors (USHPRRs). The nominal configuration of the new LEU U-10Mo plate fuel comprises a U-10Mo fuel foil enriched to slightly less than 20% U-235 (0.08” to 0.02” thick), a thin Zr interlayer/diffusion barrier (25 m thick) and a relatively thick outer can of 6061 aluminum. Currently, the Zr interlayer is clad by hot roll bonding. Previous studies and observations revealed a thinning of the zirconium (Zr) layer during this fuel fabrication process, which is not desirable from the fuel performance perspective. Coarse UMo grains, dendritic structures, Mo concentration segregation, carbides, and porosity are present in the as-cast material and can lead to a nonuniform UMo/Zr interface. The purpose of the current work is to investigate the effects of these microstructural parameters on the Zr coating variation. A microstructure-based finite-element method model was used in this work, and a study on the effect of homogenization on the interface between U-10Mo and Zr was conducted. The model uses actual backscattered electron–scanning electron microscopy microstructures, Mo concentrations, and mechanical properties to predict the behavior of a representative volume element under compressive loading during the rolling process. The model successfully predicted the experimentally observed thinning of the Zr layer in the as-cast material. The model also uses results from a homogenization model as an input, and a study on the effect of different levels of homogenization on the interface indicated that homogenization helps decrease this thinning. This model can be considered a predictive tool representing a first step for model integration and an input into a larger fuel fabrication performance model.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1339915
• Report Number(s): PNNL-25365; DN3001010; TRN: US1701483
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
BONDING
ROLLING
FINITE ELEMENT METHOD
MODERATELY ENRICHED URANIUM
MICROSTRUCTURE
INTERFACES
URANIUM 235
SCANNING ELECTRON MICROSCOPY
ZIRCONIUM
FUEL PLATES
RESEARCH REACTORS
PERFORMANCE
CARBIDES
DENDRITES
LAYERS
THICKNESS
SIMULATION
MECHANICAL PROPERTIES
FOILS
POROSITY
SEGREGATION
VARIATIONS
URANIUM BASE ALLOYS
MOLYBDENUM ALLOYS
BINARY ALLOY SYSTEMS
URANIUM-MOLYBDENUM FUELS
COATINGS
COMPRESSION
STATIC LOADS
FORECASTING