A new route to the stable capture and final immobilization of radioactive cesium

Yang, Joon-Eon; Han, Ah‐Reum; Yoon, Joo Young; Park, Hwan-Seo; Cho, Yung-Zun

doi:10.1016/j.jhazmat.2017.05.062

Cited by 30 publications

(6 citation statements)

References 41 publications

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“…Materials that have been used for ion exchange of Cs + from aqueous environments include glasses (e.g., refs − ), clay minerals (e.g., refs − ), microporous materials (e.g., refs , − ), and other materials and methods (e.g., refs − ). One concern with microporous materials is their relatively low thermal stability, a potential problem with high-temperature interactions in nuclear reactors and around uncooled spent nuclear fuel pellets. , The molecular H 2 O typically dehydrates out of zeolitic structures around 400 °C, often leading to instability.…”

Section: Introductionmentioning

confidence: 99%

In Situ Cs and H Exchange into Gaidonnayite and Proposed Mechanisms of Ion Diffusion

Celestian

Lively

2019

Inorg. Chem.

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The microporous mineral gaidonnayite Na 2 ZrSi 3 O 9 •2H 2 O was studied to better understand its ion-exchange mechanisms, specifically for Cs + and H + ions. In situ Raman spectroscopy, in situ X-ray diffraction (XRD), simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), and in situ X-ray fluorescence were used to determine the exchange processes involved. The Raman spectra contain strong peaks that can be attributed to the vibrational modes for the 3MR symmetric stretch at 500 cm −1 , Si−O−Zr−O chain stretches at 938 cm −1 , and Si−O stretching in the 1000−1100 cm −1 range. The most prominent Raman shift during ion exchange is found near the 520 cm −1 peak, which corresponds to distortions of the 3MR substructure of gaidonnayite. In all instances of this study, the 3MR exhibited the highest amount of distortion during ion exchange, and the evolution of this distortion is compared to unit-cell changes as measured from XRD data and elemental changes via XRF. The correlations between the Raman, XRD, and XRF data show rapid deformation of the 3MR during the onset of H + ion exchange in the Na form of gaidonnayite. Even when unit-cell volume changes were small (<3 Å 3 ) as in the cases for Cs + into Na-gaidonnayite and Cs + into H-gaidonnayite, significant changes in the ≈520 cm −1 peak were measured. By comparing XRD data and Raman data, and verifying the cation uptake by XRF, we were able to identify and confirm conformational changes and distortions in the crystal structure before, during, and after Cs + and H + exchange. Cs exchange occurred the fastest and with the greatest capacity when starting in the H-form at room temperature, and at elevated temperatures when starting in the Na-form.

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Section: Introductionmentioning

confidence: 99%

In Situ Cs and H Exchange into Gaidonnayite and Proposed Mechanisms of Ion Diffusion

Celestian

Lively

2019

Inorg. Chem.

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“…Waste/Waste Form. Cs nuclides are volatilized during the high-temperature heat treatment process of the nuclide management process and then captured using aluminosilicate-based adsorbents, which are primarily composed of Al 6 Si 2 O 13 (mullite) + 4SiO 2 [5,6]. Cs nuclides are captured in the form of Cs-pollucite (CsAlSi 2 O 6 ) and generated as waste [13], which is subsequently fabricated as a ceramic waste in the form of Cs-pollucite by pelletizing and sintering the waste.…”

Section: Characterization Of Csmentioning

confidence: 99%

“…Similar to the Sr nuclide waste, the radiological properties of the Sr waste form were governed by the content of Sr nuclides, which exhibited high specific radioactivity and a high heat generation rate. Hence, high specific radioactivity (∼10 [11][12] Bq/g) and high heat generation rate (∼10 [5][6] W/m 3 ) were obtained even when a small quantity of Sr nuclides was included in the waste form. e Sr waste form is expected to exhibit a high heat generation rate; therefore, the centerline temperature of the waste form can be increased based on the waste loading, which may adversely affect the thermal durability.…”

Section: Characterization Of Srmentioning

confidence: 99%

“…e spent nuclear fuel is converted to the U 3 O 8 phase through medium-temperature heat treatment between 500 °C-600 °C, where Tc-99 and Se-79 nuclides are volatilized and captured in a Ca-based absorbent [1][2][3], which is generated as waste to be manufactured in waste form. In the subsequent high-temperature heat treatment process operated between 1,400 °C and 1,500 °C [4], Cs-135/ 137 and I-129, which are semivolatile and volatile nuclides, respectively, are volatilized and captured by each adsorbent [5][6][7], which is generated as waste to be manufactured in a waste form.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Waste Generated from Nuclide Management Process in Waste Burden Minimization Technology for Spent Nuclear Fuel

Choi

Lee

et al. 2022

Science and Technology of Nuclear Installations

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To reduce the environmental burden caused by the disposal of spent nuclear fuel, waste burden minimization technology is currently being developed at the Korea Atomic Energy Research Institute. The technology includes a nuclide management process that can maximize disposal efficiency by selectively separating and collecting major nuclides in spent nuclear fuel. To manufacture a waste form of high durability, the characteristics of the waste generated during the process should be evaluated. In this study, the physical, radiological, and thermal characteristics of the waste and waste forms for major nuclides (Cs, Sr, I, transuranic/rare earth, and Tc/Se) generated in the nuclide management process were analyzed. In the case of Cs nuclides, characterization was conducted according to the capture rate of the adsorbent in the high-temperature heat treatment process; meanwhile, in the case of Sr nuclides, characterization was performed by considering the ratio of similar nuclides in the chlorination process. For I nuclide, analysis was performed based on the available waste form, and for TRU/RE and Tc/Se nuclides, analysis was performed by considering chlorination and mid-temperature heat treatment. The radioactivity and heat generation rate of each waste and waste form were evaluated over a period of 1,000 years. The results of this study could be used to derive the centerline temperature for the thermal stability evaluation of waste forms and for the feasibility evaluation of each disposal system considered in the waste burden minimization technology.

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“…Growing nuclear safety problems require more effective solutions for retaining radionuclides. Currently, a significant amount of low and intermediate-level radioactive waste has been accumulated (~24 million m 3 ) [1,2]. One of the most hazardous radionuclides is radioactive cesium ( 137 Cs).…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Cs Immobilization within a Sodalite Framework: The Role of Alkaline Cations and the Si/Al Ratio

Kasprzhitskii,

Ermolov,

Mischinenko

et al. 2023

IJMS

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Conditioning of radioactive waste generated from the operation of medical institutions, nuclear cycle facilities, and nuclear facilities is important for the safety of the environment. One of the most hazardous radionuclides is radioactive cesium. There is a need for more effective solutions to contain radionuclides, especially cesium (Cs+). Geopolymers are promising inorganic materials that can provide a large active surface area with adjustable porosity and binding capacity. The existence of nanosized zeolite-like structures in aluminosilicate gels was shown earlier. These structures are candidates for immobilizing radioactive cesium (Cs+). However, the mechanisms of their interactions with the aluminosilicate framework related to radionuclide immobilization have not been well studied. In this work, the influence of alkaline cations (Na+ or K+) and the aluminosilicate framework structure on the binding capacity and mechanism of interaction of geopolymers with Cs+ is explored in the example of a sodalite framework. The local structure of the water molecules and alkaline ions in the equilibrium state and its behavior when the Si/Al ratio was changed were studied by DFT.

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A new route to the stable capture and final immobilization of radioactive cesium

Cited by 30 publications

References 41 publications

In Situ Cs and H Exchange into Gaidonnayite and Proposed Mechanisms of Ion Diffusion

In Situ Cs and H Exchange into Gaidonnayite and Proposed Mechanisms of Ion Diffusion

Characterization of Waste Generated from Nuclide Management Process in Waste Burden Minimization Technology for Spent Nuclear Fuel

Mechanism of Cs Immobilization within a Sodalite Framework: The Role of Alkaline Cations and the Si/Al Ratio

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