High energy X-ray diffraction measurement of residual stresses in a monolithic aluminum clad uranium–10wt% molybdenum fuel plate assembly

Brown, Donald W.; Okuniewski, Maria A.; Almer, Jonathan; Balogh, Levente; Clausen, B.; Okasinski, John; Rabin, B. H.

doi:10.1016/j.jnucmat.2013.05.064

Cited by 14 publications

(31 citation statements)

References 22 publications

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“…However, in the cases where a high dislocation density was present in the bare foil, the dislocation density decreased significantly during bonding. That is to say, worked foils recovered during the bonding step, consistent with previous studies [9]. It is important to recognize that the flow strength of the U-10Mo fuel foil evolves throughout processing as evidenced by the changing dislocation density.…”

Section: Microstructural Evolution During Claddingsupporting

confidence: 87%

“…In the context of this work, we will interpret the peak breadth as indicative of dislocation density, as discussed in past work [9]. Without going into detail, the  1 profile parameter incorporated in the GSAS TOF profile function 1 [20] is related to the root mean square strain, [20], where C is the diffractometer constant determined from the instrumental calibration and  i is the instrumental broadening, determined in this case from the scattering from the annealed copper foil.…”

Section: 33dislocation Densitymentioning

confidence: 99%

“…Acceptable reference samples were not available for the aluminum or the U-10Mo because it was not possible to fabricate a reference sample without sending it through the identical thermomechanical procedures. For instance, it is known that the Mo content changes during the HIP'ing procedure as -U precipitates [9,25]. The reference lattice parameters of the U-10Mo and Al were determined by forcing the normal component of the stress ( 33 ) to zero near the center of the plate, far from any boundary.…”

Section: Residual Stressmentioning

confidence: 99%

“…Microstructural studies of as-processed clad monolithic fuel foils are to be found in the literature but tend to focus on phases formed at the interfaces [4][5][6] or residual stresses between the fuel, diffusion prevention layer, and cladding [7][8][9][10]. Previous high energy X-ray and neutron diffraction studies report a strong in-plane compressive stress in the U-10Mo foil in a clad fuel plane and observed a significant reduction of dislocation density following the HIP bonding step [9,10]. The residual stresses in the final full size plates are important because they could potentially cause distortion during use resulting in blocking of the relatively narrow water flow channels between fuel plates creating a local hot spot.…”

Section: Introductionmentioning

confidence: 99%

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Neutron diffraction measurement of residual stresses, dislocation density and texture in Zr-bonded U-10Mo “mini” fuel foils and plates

Brown

Okuniewski

Sisneros

et al. 2016

Journal of Nuclear Materials

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Al clad U-10Mo fuel plates are being considered for conversion of several research reactors from high-enriched to low-enriched U fuel. Neutron diffraction measurements of the textures, residual phase stresses, and dislocation densities in the individual phases of the mini-foils throughout several processing steps and following hot-isostatic pressing to the Al cladding, have been completed. Recovery and recrystallization of the bare U-10Mo fuel foil, as indicated by the dislocation density and texture, are observed depending on the state of the material prior to annealing and the duration and temperature of the annealing process. In general, the cladding procedure significantly reduces the dislocation density, but the final state of the clad plate, both texture and dislocation density, depends strongly on the final processing step of the fuel foil. In contrast, the residual stress state of the final plate is dominated by the thermal expansion mismatch of the constituent materials.

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Section: Microstructural Evolution During Claddingsupporting

confidence: 87%

Section: 33dislocation Densitymentioning

confidence: 99%

Section: Residual Stressmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Neutron diffraction measurement of residual stresses, dislocation density and texture in Zr-bonded U-10Mo “mini” fuel foils and plates

Brown

Okuniewski

Sisneros

et al. 2016

Journal of Nuclear Materials

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“…Some fuel plates (MURR, HFIR, and ATR) are then cold-formed after HIP-bonding. The microstructural evolution of the foil during processing may be important, as cracking, preferential deformation, localized residual stresses, large inclusions, or differences in local phase stability may contribute to failure during fuel plate fabrication [15][16][17][18][19][20] or in-service. To date, apart from large inclusions that have been problematic during processing [16], specific microstructural characteristics have not been linked to inservice failures.…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution of a uranium-10 wt.% molybdenum alloy for nuclear reactor fuels

Clarke

McCabe

et al. 2015

Journal of Nuclear Materials

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Low-enriched uranium-10 wt.% molybdenum (LEU-10wt.%Mo) is of interest for the fabrication of monolithic fuels to replace highly-enriched uranium (HEU) dispersion fuels in high performance research and test reactors around the world. In this work, depleted uranium-10wt.%Mo (DU-10wt.%Mo) is used to simulate the solidification and microstructural evolution of LEU-10wt.%Mo. Electron backscatter diffraction (EBSD) and complementary electron probe microanalysis (EPMA) reveal significant microsegregation present in the metastable γ-phase after solidification. Homogenization is performed at 800 and 1000 °C for times ranging from 1 to 32 h to explore the time-temperature combinations that will reduce the extent of microsegregation, as regions of higher and lower Mo content may influence local mechanical properties and provide preferred regions for γ-phase decomposition. We show for the first time that EBSD can be used to qualitatively assess microstructural evolution in DU-10wt.%Mo after homogenization treatments. Complementary EPMA is used to quantitatively confirm this finding. Homogenization at 1000 °C for 2 to 4 h reduces the regions that contain 8 wt.% Mo or lower, whereas homogenization at 1000 °C for longer than 8 h effectively saturates Mo chemical homogeneity, but results in substantial grain growth. The appropriate homogenization time will depend upon additional microstructural considerations, such as grain growth and intended subsequent processing. Higher carbon LEU-10wt.%Mo generally contains more inclusions within the grains and at grain boundaries after solidification. The effect of these inclusions on microstructural evolution (e.g. grain growth) during homogenization and as potential γ-phase decomposition nucleation sites is unclear, but likely requires additional study.

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Residual Stress Measurements in Extreme Environments for Hazardous, Layered Specimens

et al. 2022

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Background In nuclear fuel plates of low-enriched U-10Mo (LEU) clad with aluminum by hot isostatic pressing (HIP), post-irradiation stresses arising during reactor shutdown are a major concern for safe reactor operations. Measurement of those residual stresses has not previously been possible because the high radioactivity of the plates requires handling only by remote manipulation in a hot cell. Objective The incremental slitting method for measuring through-thickness stress profiles was modified, and a system for automated, remote operation was built and tested. Methods Experimental modifications consisted of replacing electric-discharge machining (EDM) with a small end mill and strain-gauge measurements with cantilever displacement measurements. The inverse method used to calculate stresses was the pulse-regularization method modified to allow discontinuities across material interfaces. The new system was validated by comparing with conventional slitting on a depleted U-10Mo (DU) fuel plate. Results The new system was applied to two measurements each on six as-fabricated (pre-irradiation) LEU miniature fuel plates. Variations between the measurements at two locations in the same plate were strongly correlated with measured geometrical heterogeneity in the plate—a tilt in the fuel foil. Compressive stresses in the U-10Mo were shown to increase from 20 to 250 MPa as the ratio of aluminum thickness to U-10Mo thickness increased causing increased constraint during cooling. Faster cooling rates during processing also increased stress magnitudes. Conclusions The measurements trends agreed with data in the literature from similar plates made with DU, which further validates the method. Because other methods are impractical in a hot cell, the modified slitting method is now poised for the first measurements of post-irradiation stresses.

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High energy X-ray diffraction measurement of residual stresses in a monolithic aluminum clad uranium–10wt% molybdenum fuel plate assembly

Cited by 14 publications

References 22 publications

Neutron diffraction measurement of residual stresses, dislocation density and texture in Zr-bonded U-10Mo “mini” fuel foils and plates

Neutron diffraction measurement of residual stresses, dislocation density and texture in Zr-bonded U-10Mo “mini” fuel foils and plates

Microstructural evolution of a uranium-10 wt.% molybdenum alloy for nuclear reactor fuels

Residual Stress Measurements in Extreme Environments for Hazardous, Layered Specimens

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