Vitrification des déchets radioactifs

Advocat, T.; Dussossoy, Jean-Luc; Petitjean, V.

doi:10.51257/a-v1-bn3664

Cited by 6 publications

(6 citation statements)

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“…The greatest change was observed for the C15 glass (Figure 13B), which reached an η R of 1.35 after 8 h. The gross increase for this condition was from 9.2 to 12.3Pa.s, which is negligible in the context of the vitrification process. 72 The results suggest that the increase in viscosity was mainly due to evaporation, as only an increase of about 3% would be expected due to crystallization.…”

Section: Rheological Behaviormentioning

confidence: 89%

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Precipitation of cerianite crystals and its effect on the rheology of a simplified nuclear glass melt

Jiusti,

Regnier,

Machado

et al. 2023

Int J of Appl Glass Sci

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In France, high‐activity level wastes resulting from nuclear fission are conditioned in a homogeneous sodium‐aluminoborosilicate glass by high‐temperature vitrification. The tolerance of even a small fraction of crystals could enable an increase in the waste loadings, in addition to promoting process flexibility. If the waste loading were to be increased in French nuclear glass, cerianite (CeO2) crystals could precipitate. In this study, we investigated the cerianite crystallization in a simplified nuclear glass melt at different temperatures, Ce2O3 wt%, and shear conditions. Furthermore, the evolution of the viscosity along with cerianite precipitation was followed. It was found that Ce2O3 is highly soluble in the glass melt, as even for a Ce2O3 wt% as high as 10% wt, the cerianite fraction in dynamic conditions at 1100°C after 8 h of crystallization was less than 1% vol. In addition, shear strongly accelerates cerianite crystallization and a high Ce2O3 content can engender the precipitation of highly branched dendrites. The evolution of the cerianite fraction did not significantly affect the viscosity of the glass melt. Finally, unlike what has been observed in the well‐known platinum group metal (PGM)‐bearing melts, a glass melt containing .8 vol% of cerianite crystals remains Newtonian.

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Section: Rheological Behaviormentioning

confidence: 89%

“…To summarize, our results show that such a small cerianite crystal fraction will not affect the operation of the vitrification process due to viscosity changes. 72 A study on the settling of cerianite crystals in static and dynamic conditions would be the next step to verify its effect on the process.…”

Section: Rheological Behaviormentioning

confidence: 99%

Precipitation of cerianite crystals and its effect on the rheology of a simplified nuclear glass melt

Jiusti,

Regnier,

Machado

et al. 2023

Int J of Appl Glass Sci

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“…The material used in this study was a simulated nuclear glass containing 3 wt.% of PGM particles. The glass was produced in the full-scale pilot unit installed at CEA Marcoule [20].…”

Section: Methodsmentioning

confidence: 99%

Influence of platinum group metal particle aggregation on the rheological behavior of a glass melt

Machado

Pereira

Neyret

et al. 2022

Journal of Nuclear Materials

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“…The borosilicate glass containing PGM particles used in this work was elaborated on a fullscale pilot unit installed at CEA Marcoule [4]. The unit follows the two step calcinationvitrification protocol and was equipped with a cold-crucible melter working at 1200°C..…”

Section: Methodsmentioning

confidence: 99%

“…The vitrification technology is based on the use of induction, in the crucible (hot crucible melter) or directly in the glass (cold crucible melter [1]). The nuclear glass is then poured into metal containers and then stored in wells before their future storage in deep geological formations [4].…”

Section: Introductionmentioning

confidence: 99%

Thixotropic behavior of a glass melt of nuclear interest containing platinum group metal particles

et al. 2022

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Contrary to some other elements such as Iron, Nickel and Chromium, the Platinum Group Metals particles (PGM) are not incorporated chemically in molten glasses. These particles are generally found in nuclear borosilicate glasses resulting from the melting, at 1200°C, of a glass precursor and fission products issued from spent fuel reprocessing. During the melting step, the presence of theses metals as suspended particles of a few microns has an impact on the rheological properties of the material, leading to a Non-Newtonian behavior. Their impact on the process is the object of characterization and modeling of many studies that have established that the melt presents a shear-thinning and thixotropic behavior. At high shear rate, the glass behaves as a suspension of individual particles, whose rheological behavior is controlled by the viscosity of the vitreous matrix. On the other hand, at low shear rate, below a stress threshold, and above a certain volume fraction in PGM particles, the formation of aggregates composed of needle-like Ru/RuO2 chains and Pd-Rh-Te spherical particles, strongly influences the viscosity of the glass. In this work, a deeper analysis of the thixotropic behavior of a simulated nuclear glass melt containing 3.0 wt% (1.02 vol%) of PGM particles will be presented. Steady and transient state measurements were performed over a wide shear rate range using an imposed-stress rheometer at temperatures ranging from 1100 to 1250 °C. Using Houska model, this work shows that it is possible to predict the transient behavior of the sample from their steady-state rheological behavior.

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Vitrification des déchets radioactifs

Cited by 6 publications

References 0 publications

Precipitation of cerianite crystals and its effect on the rheology of a simplified nuclear glass melt

Precipitation of cerianite crystals and its effect on the rheology of a simplified nuclear glass melt

Influence of platinum group metal particle aggregation on the rheological behavior of a glass melt

Thixotropic behavior of a glass melt of nuclear interest containing platinum group metal particles

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