Review of sintering and densification in nuclear fuels: Physical mechanisms, experimental results, and computational models

Greenquist, Ian; Tonks, Michael; Zhang, Yongfeng

doi:10.1016/j.jnucmat.2018.03.046

Cited by 24 publications

(6 citation statements)

References 137 publications

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“…Pressing at 1 atm and sintering are used to manufacture nuclear fuel based on U [149] and with additions of Th, Pu, and minor actinides (Np, Am, and Cm) [150,151]. The process takes place above 1500 • C in a reducing/inert environment.…”

Section: Influence Of Synthesis Conditions On the Structure Of Zircon...mentioning

confidence: 99%

“…The advantages of sintering are simple equipment suitable for obtaining ceramic and glass ceramic samples of various sizes. CPS is used for sintering UO 2 [149] and MOX fuel with Th, Pu, Np, Am, and Cm [150,151] at 1600-1750 • C for 4-24 h in an inert or reducing (4% H 2 /Ar) environment. Based on the CPS method, a technology for obtaining pyrochlore matrices with Pu was created in the USA [66,103,105,147].…”

Section: Technologies For Fabrication Of Zirconolite Wasteformsmentioning

confidence: 99%

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Zirconolite Matrices for the Immobilization of REE–Actinide Wastes

et al. 2023

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The structural and chemical properties of zirconolite (ideally CaZrTi2O7) as a host phase for separated REE–actinide-rich wastes are considered. Detailed analysis of both natural and synthetic zirconolite-structured phases confirms that a selection of zirconolite polytype structures may be obtained, determined by the provenance, crystal chemistry, and/or synthesis route. The production of zirconolite ceramic and glass–ceramic composites at an industrial scale appears most feasible by cold pressing and sintering (CPS), pressure-assisted sintering techniques such as hot isostatic pressing (HIP), or a melt crystallization route. Moreover, we discuss the synthesis of zirconolite glass ceramics by the crystallization of B–Si–Ca–Zr–Ti glasses containing actinides in conditions of increased temperatures relevant to deep borehole disposal (DBD).

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Section: Influence Of Synthesis Conditions On the Structure Of Zircon...mentioning

confidence: 99%

Section: Technologies For Fabrication Of Zirconolite Wasteformsmentioning

confidence: 99%

Zirconolite Matrices for the Immobilization of REE–Actinide Wastes

et al. 2023

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“…A uniform particle size was selected because it facilitates a relatively high interface width, which in turn allows for a coarser mesh and lower computational cost. This decision should not significantly affect the sintering results because the initial particle size distribution only negligibly affects the sintering behavior [11]. The particles were sized at 700 nm in diameter to match the average diameter of particles sintered in the experimental portion of this project.…”

Section: Simulation Setupmentioning

confidence: 99%

“…The thermodynamics and kinetics of the process are complex and governed by the interactions between point defects, grain boundaries (GBs), surfaces, pressure, and temperature. Furthermore, sintering is highly sensitive to relatively small changes in factors such as the O/U ratio of the fuel, the sintering atmosphere, and the presence of minor impurities (e.g., dopants or taggants) [11]. The porosity and grain size distribution that sintering creates affects the performance of UO2 during reactor operation, and the largest effect is on FGR.…”

Section: Introductionmentioning

confidence: 99%

Phase Field Sintering Simulations of Tagged UO<sub>2</sub>

Greenquist¹,

Cheniour²,

Tash³

et al. 2023

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Isotopic taggants are being considered as an additive for UO2 manufacturing to improve nuclear security. Before taggants can be adopted, it must be determined whether taggants have any effect on the fuel microstructure or performance. As part of this effort, a grand potential formulation of the phase field method was used to model untagged, Cr-tagged, and Fe-tagged UO2. The simulations were compared to determine whether the taggants had any effect on fuel density or grain size. The results suggest that the taggants will not affect the density or grain size, but these findings may not be reliable because of high uncertainty. Causes of the uncertainty were discussed, and future work is proposed to reduce the model uncertainty.

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“…Sintering is a process through which a powder is transformed into solid or porous mass by heating and avoiding liquefaction. Sintering has long been used in the fabrication of nuclear fuel converting UO 2 powders to a densified pellet (Greenquist et al, 2018). Traditional sintering can take hours to perform, however the process can be accelerated through several means.…”

Section: Sinteringmentioning

confidence: 99%

Review of recent developments in iodine wasteform production

et al. 2022

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Radioiodine capture and immobilization is not only important to consider during the operation of reactors (i.e., I-131), during nuclear accidents (i.e., I-131 and I-129) or nuclear fuel reprocessing (i.e., I-131 and I-129), but also during disposal of nuclear wastes (i.e., I-129). Most disposal plans for I-129-containing waste forms (including spent nuclear fuel) propose to store them in underground repositories. Here, iodine can be highly mobile and, given its radiotoxicity, needs to be carefully managed to minimize long-term environmental impacts arising from disposal. Typically, any process that has been used to capture iodine from reprocessing or in a reactor is not suitable for direct disposal, rather conversion into a wasteform for disposal is required. The objectives of these materials are to use either chemical immobilization or physical encapsulation to reduce the leaching of iodine by groundwaters. Some of the more recent ideas have been to design capture materials that better align with disposal concepts, making the industrial processing requirements easier. Research on iodine capture materials and wasteforms has been extensive. This review will act as both an update on the state of the research since the last time it was comprehensively summarized, and an evaluation of the industrial techniques required to create the proposed iodine wasteforms in terms of resulting material chemistry and applicability.

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Review of sintering and densification in nuclear fuels: Physical mechanisms, experimental results, and computational models

Cited by 24 publications

References 137 publications

Zirconolite Matrices for the Immobilization of REE–Actinide Wastes

Zirconolite Matrices for the Immobilization of REE–Actinide Wastes

Phase Field Sintering Simulations of Tagged UO<sub>2</sub>

Review of recent developments in iodine wasteform production

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