The Leaching of Pu, Am, Np and Tc from High-Level Waste Glasses in Clay Media

Lemmens, Karel; Iseghem, P. Van; Wang, L.

doi:10.1557/proc-294-147

Cited by 8 publications

(5 citation statements)

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“…For these systems under irradiation, the measured pH is around 0.5-1 pH unit lower than that those measured in the reference experiment leachates; however, once the silicon releases are stabilized, the pH values also remain stable over time. This acidification of the irradiated glass leachates has already been observed in pure water in previous studies [36][37][38] and under environmental conditions 39,40 . This could be due to radiolysis effects, mainly air radiolysis, which is known to induce nitric acid production in solution 36 .…”

Section: Introductionsupporting

confidence: 82%

Alpha dose rate and decay dose impacts on the long-term alteration of HLW nuclear glasses

et al. 2021

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In the prospect of deep geological disposal, the long-term behavior of high-level nuclear glasses has to be investigated regarding alpha radiation induced by long-life minor actinides. The present study focuses on the effects of alpha radiation on the long-term chemical reactivity of R7T7-type glasses, by separately considering the alpha dose rate and the alpha decay dose. Old SON68 glasses doped with 238/239PuO2 or 244CmO2 were studied to simulate high alpha dose rates corresponding to an early water ingress and a high level of alpha decay doses corresponding to long-term disposal conditions. A part of the 238/239Pu-doped glass block was annealed to fully recover the irradiation-induced damage accumulated since the glass was fabricated and to dissociate the effect of the alpha dose rate from that of the alpha decay dose. The glasses were then leached under static conditions at 90 °C for several years. The results showed that the residual alteration rate is not affected by the alpha dose rate over a wide range of dose rate values expected under disposal conditions: this glass remained relatively insensitive to the alpha radiolysis phenomena at the glass–water interface. However, over the duration of the experiments, the residual alteration rate of the damaged 238/239Pu-doped glass was enhanced compared to that of the annealed glass. This result is in agreement with those obtained on the 244Cm-doped glass and with reported values in the literature on simplified externally irradiated glasses, indicating that the ballistic effects of the recoil nuclei are responsible for this increase in the residual alteration rate.

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Section: Introductionsupporting

confidence: 82%

Alpha dose rate and decay dose impacts on the long-term alteration of HLW nuclear glasses

et al. 2021

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“…Leach tests in a slurry of Boom clay showed retention of Np and Pu in layers formed on R7T7 glass and on a Pamela glass SM513, but a third glass, Pamela SM527, did not generate an alteration layer and did not retain these elements [268]. Technetium was not retained by the layers.…”

Section: Effects Of Other Materials On Actinide Dispositionmentioning

confidence: 92%

“…The Pu and Am released from the glass was strongly sorbed onto the clay, while the Tc and Np were only partially sorbed onto the clay. The plutonium and americium had attained steady-state concentrations after two years of reaction (both below 2 x 10-9 M), while neptunium was present at about 2 x 10-6 M and technetium at about 4x10-7 M. Further, addition of Fe 2 03 to the tests slowed the corrosion of all three glasses by at least a factor of 68 [268].…”

Section: Effects Of Other Materials On Actinide Dispositionmentioning

confidence: 96%

The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

Ebert

1995

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Argonne National Lahoratory. wi1th facilitie, in the states of liiinois and Idaho. is owned by the united States govern lent, and operated by The Un diversity of Chicago under the provisions of a contract with thie department of Enery. DISCLAIM ER THE FFFECTS OF THE GLASS SURFACE AREA/SOLUTION VOLUME RATIO ON GLASS CORROSION: A CRITICAL REVIEW William L. Ebert ABSTRACTThis report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution ok corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SAN ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Corrosion of borosilicate waste glasses results in the dissolution of soluble components and the accumulation of sparingly soluble components in a layer on the surface of the corroding glass. Laboratory tests performed to distinguish the effects of the solution chemistry and the surface layer on the glass corrosion rate have shown the rate to be controlled primarily by the solution chemistry. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SAN are discussed with regard to the effects of SAN on the solution chemistry. The effects of the SA/V ratio observed in static tests can be understood based on the effects of the solution chemistry on glass corrosion behavior. Test results show several remaining issues with regard to the long-term glass corrosion behavior: Can the SAN ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times? Is the alteration of the glass surface the same in tests conducted at different SAN, and in tests conducted with monolithic and crushed glass samples? What are the effects of the SAN and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. I 2 SUMMARYThis report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume ratio (SA/V) on the corrosion behavior of borosilicate waste glasses. The effects of the SA/ occur through dilution of corrosion products and through the effects of the corrosion products on the glass corrosion mechanism and rate. Therefore, the effects of the SA/V on glass corrosion are discussed in terms of the various effects of t...

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“…A few studies performed the static leaching experiments to examine the leaching behavior of 99 Tc in 99 Tc doped borosilicate glass in disposal environment (Lemmens & Wang, 1992;Pirlet et al, 2002Pirlet et al, , 2004. A mixture of clay with synthetic pore water was used as the leachant to simulate the actual interstitial pore water.…”

Section: Solubility Of Tc and Re From Glass Waste Formsmentioning

confidence: 99%

Technetium (Tc)/Rhenium (Re) solubility and leaching behavior from waste forms: An overview

et al. 2023

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Technetium-99 (99Tc), a radionuclide generated from nuclear industry is a great environmental concern because of its long half-life (2.13 × 105 years) and high mobility in environment. Therefore, apposite management of 99Tc is imperative to control its hazardous radiological impact on humans and other livings. So far, the major strategy implementation has been the solidification and immobilization of 99Tc radioactive waste in various matrices as waste forms and disposal in deep geological repository. However, by passing the time, 99Tc may leach out/solubilize from the waste forms under different geochemical/environmental conditions. In this minireview, we discuss some key contributions towards the solubility of 99Tc and rhenium (Re; a well-known surrogate of 99Tc) from different waste forms. Specifically, we review the solubility of 99Tc from glass, cement, ceramic, and geopolymer waste forms. The final section (conclusion) presents a short summary and future challenges need be addressed to impede the solubility of 99Tc from the designed waste forms. We believe this minireview will be beneficial to provide a significant insight on the solubility of 99Tc from aforementioned waste forms and in the design of robust matrices to minimize/prevent 99Tc migration in various environments.

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The Leaching of Pu, Am, Np and Tc from High-Level Waste Glasses in Clay Media

Cited by 8 publications

References 0 publications

Alpha dose rate and decay dose impacts on the long-term alteration of HLW nuclear glasses

Alpha dose rate and decay dose impacts on the long-term alteration of HLW nuclear glasses

The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

Technetium (Tc)/Rhenium (Re) solubility and leaching behavior from waste forms: An overview

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