Post-irradiation examination of uranium–7wt% molybdenum atomized dispersion fuel

Leenaers, A.; Berghe, S. Van den; Koonen, E.; Jarousse, C.; Huet, François; Trotabas, M.; Boyard, M.; Guillot, Samuel; Sannen, L.; Verwerft, Marc

doi:10.1016/j.jnucmat.2004.07.004

Cited by 168 publications

(114 citation statements)

References 9 publications

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“…9 The development of this type of interaction layer that contains only U, Mo, and Al is unfavorable since the layer does not behave well during irradiation. 1 Due to the lack of development of Si-depleted phases in the interaction zones in this study, it can be concluded that the times at the various temperatures are not excessive such that the decomposition of U-7Mo could impact the development of the interaction zones in terms of causing formation of Si-depleted phases. Clearly, decomposed regions were present in the U-7Mo alloy in all the samples.…”

Section: Development Of Fmi Layers In Annealing Study Samplesmentioning

confidence: 70%

“…For U-Mo dispersion fuels with pure Al as the matrix, it has been observed that relatively large porosity can develop at the FMI layer/matrix interface during irradiation, and this porosity can link up and cause fuel plate failure. 1 To potentially remedy this phenomenon, it has been suggested that the addition of Si to the matrix of a dispersion fuel can influence the development of a FMI layer such that it will exhibit more stability during irradiation. 2 Irradiation experiments have shown that in fact U-7Mo dispersion fuel plates with enough Si added to the matrix do exhibit better irradiation behavior compared to irradiated fuel plates with pure Al matrix.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Annealing Treatments for Producing Si-Rich Fuel/Matrix Interaction Layers in Low-Enriched U-Mo Dispersion Fuel Plates Rolled at a Low Temperature

Keiser¹,

Jue²,

Woolstenhulme³

2010

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During fabrication of U-7Mo dispersion fuels, exposure to relatively high temperatures affects the final microstructure of a fuel plate before it is inserted into a reactor. One impact of this high temperature exposure is a chemical interaction that can occur between dissimilar materials. For U-7Mo dispersion fuels, the U-7Mo particles will interact to some extent with the Al or Al alloy matrix to produce interaction products. It has been observed that the final irradiation behavior of a fuel plate can depend on the amount of interaction that occurs at the U-7Mo/matrix interface during fabrication, along with the type of phases that develop at this interface. For the case where a U-7Mo dispersion fuel has a Si-containing Al alloy matrix and is rolled at around 500°C, a Si-rich interaction product has been observed to form that can potentially have a positive impact on fuel performance during irradiation. This interaction product can exhibit stable irradiation behavior and it can act as a diffusion barrier to additional U-Mo/matrix interaction during irradiation. However, for U-7Mo dispersion fuels with softer claddings that are rolled at lower temperatures (e.g., near 425°C), a significant interaction layer has not been observed to form. As a result, the bulk of any interaction layer that develops in these fuels happens during irradiation, and the layer that forms may not exhibit as stable a behavior as one that is formed during fabrication. Therefore, it may be beneficial to add a heat treatment step during the fabrication of dispersion fuel plates with softer cladding alloys that will result in the formation of a uniform, Si-rich interaction layer that is a few microns thick around the U-Mo fuel particles. This type of layer would have characteristics like the one that has been observed in dispersion fuel plates with AA6061 cladding that are fabricated at 500°C, which may exhibit increased stability during irradiation. This report discusses the result of annealing experiments that were performed using samples from fuel plates that were fabricated at 425°C that had Alloy 5052 cladding. As part of these experiments, samples with Al-Si matrices that had different Si contents were tested. The samples had Al-2Si, Al-4Si, Al-5Si, or Al-6Si as the matrix alloy. The heat treatment temperatures and times that were investigated were 450°C (4 hours), 475°C (4 hours), and 500°C (2 hours) for all the matrix alloy compositions and 525°C (1 hour) for just the Al-4Si and Al-6Si matrix alloy compositions. The results of these experiments showed that the initial interaction layers that form around the U-7Mo particles during fabrication at 425°C continue to grow in thickness and uniformity during each of the heat treatments, though the composition of the layers remains similar to that observed in the as-fabricated samples. The Al-6Si matrix sample annealed at 450°C for 4 hours and the Al-5Si and Al-6Si matrix samples annealed at 475°C for 4 hours formed fuel/matrix interaction layers most similar to those observed in fue...

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Section: Development Of Fmi Layers In Annealing Study Samplesmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Evaluation of Annealing Treatments for Producing Si-Rich Fuel/Matrix Interaction Layers in Low-Enriched U-Mo Dispersion Fuel Plates Rolled at a Low Temperature

Keiser¹,

Jue²,

Woolstenhulme³

2010

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“…IRIS-1 (U-7Mo) [12] FUTURE (U-7Mo) [13] KOMO-2 (lower T) [11] KOMO-2 (higher T) [11] Fig. 7 Pseudo-ternary diagram of U-Mo-Al-Si showing IL composition data from in-pile tests with pure Al matrix.…”

Section: Al-to-u Ratiomentioning

confidence: 99%

Improved performance of U-Mo dispersion fuel by Si addition in Al matrix.

Kim¹,

Hofman²

2011

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“…78 Another early paper describing characteristics of IL layers produced in-reactor found several layers, each with a different composition: one composition near (U,Mo)Al 3 and the other near (U,Mo)Al 4.4 . 55 Note that these early studies contained no real phase identification. 41 showed that U-10Mo dispersed in Al formed an IL when irradiated and, using NDA, identified the major phase in the IL as (U,Mo)Al 3 , and essentially no "higher" aluminides, like UMo 2 Al 20 or U 6 Mo 4 Al 43 , often observed in diffusion couple tests.…”

Section: Multi-layered Ilmentioning

confidence: 99%

Interaction Layer Characteristics in U-xMo Dispersion/Monolithic Fuels

Porter¹

2010

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SUMMARYPublished data concerning the interaction layer (IL) formed between U-xMo fuel alloy and aluminum (Al)-based matrix or cladding materials was reviewed, including the effects of silicon (Si) content in the matrix/cladding, molybdenum (Mo) content in the fuel, pre-irradiation thermal treatments, irradiation, and test temperature. The review revealed that tests conducted in the laboratory produce results different from those conducted in an irradiation environment. However, the laboratory testing relates well to thermal treatments performed prior to irradiation and helps in understanding the effects that these pre-irradiation treatments have on in-reactor performance. A small, Si-enriched IL, formed during a step in the fabrication process, seems to be stable during irradiation, helping to prevent the rapid growth of an irradiation-induced IL. Moreover, the Si-enriched IL seems to be important in delaying the onset of rapid growth of fission gas bubbles.Conclusions from irradiated fuels data have been repeated many times in the literature review. However, as related to the "Desired Characteristics of the IL" mentioned near the beginning of this report, several more conclusions can be drawn:1. An IL with phases akin to UAl 3 is desired for optimum fuel performance, but at low temperatures, and especially in an irradiation atmosphere, the desired (Al+Si)/(U+Mo) ratio of three is difficult to produce. When the fuel operating temperature is low, it is important to create a pre-irradiation IL enriched in Si. This pre-formed IL is relatively stable, performs well in terms of swelling resistance, and prevents rapid IL growth during irradiation. Fabrication-related heat treatments should be limited in order to maintain a thin, Si-enriched layer containing potentially beneficial phases.2. At higher operating temperatures (>150-170°C), IL formation in reactor may not be so dependent on pre-irradiation IL formation, especially at high burnup; a pre-fabricated IL seems to be less stable at high burnup and high operating temperature. Moreover, the (Al+SI)/(U+Mo) ratio of three occurs more often at higher temperature. For these two reasons, it is important at high operating temperature to also have a matrix with significant Si content to create an IL in-reactor with the right characteristics.3. Out-of-reactor testing seems to indicate that Si in the matrix material is required in some concentration (2%, 5%, ?) to provide for a thin, Si-enriched IL formed before irradiation of a fuel plate. It ensures that the IL contains beneficial phases or prevents formation of some known to promote poor fuel performance. Significant progress has been made in determining the desired characteristics of the IL.4. The use of a fuel with stable gamma phase appears to allow more predictable performance regarding both a beneficial pre-irradiation layer and the fuel performance (low swelling) to high burnup. Destabilization of the gamma phase may create problems with IL breakaway growth.5. A theory whereby prevention of the U 6 Mo 4 Al 43 comp...

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Post-irradiation examination of uranium–7wt% molybdenum atomized dispersion fuel

Cited by 168 publications

References 9 publications

Evaluation of Annealing Treatments for Producing Si-Rich Fuel/Matrix Interaction Layers in Low-Enriched U-Mo Dispersion Fuel Plates Rolled at a Low Temperature

Evaluation of Annealing Treatments for Producing Si-Rich Fuel/Matrix Interaction Layers in Low-Enriched U-Mo Dispersion Fuel Plates Rolled at a Low Temperature

Improved performance of U-Mo dispersion fuel by Si addition in Al matrix.

Interaction Layer Characteristics in U-xMo Dispersion/Monolithic Fuels

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