High-temperature heat capacity and density of simulated high-level waste glass

Sugawara, Takuo; Katsuki, Junki; Shiono, Takashi; Yoshida, Satoshi; Matsuoka, Jun; Minami, Kazuhiro; Ochi, Eiji

doi:10.1016/j.jnucmat.2014.07.055

Cited by 11 publications

(19 citation statements)

References 58 publications

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“…All samples exhibited a ~25% increase in heat capacity with a 375°C increase in temperature. This was consistent with the literature and also indicated that the temperature range of measurement was below the Debye temperature . At the Debye temperature, all phonon modes would be active, and the relative heat capacity increase with temperature would drastically reduce.…”

Section: Discussionsupporting

confidence: 91%

“…Heat capacity values had a higher variability (± 5%) than found for thermal diffusivity, but the overall increase was still larger than the variability. The reported values were similar to those reported for other borosilicate waste glasses in the literature . Figure showed the heat capacity for the NBS glasses as a function of temperature.…”

Section: Resultssupporting

confidence: 85%

“…The specific heat capacity was calculated using the temperature rise of the measured specimen and the energy input of the laser pulse as shown in Equation ,

c_{p} = \frac{italicaAq}{m Δ T_{m}}

where a is the absorptivity of the sample face, A is the surface area of the samples, q is the energy density of the laser pulse, m is the mass of the sample, and Δ T m is the maximum temperature rise measured on the back face of the specimen. Aluminum, graphite, and a previously studied waste glass by Sugawara were used as calibration standards . Diffusivity measurements were within ±1% and heat capacity measurements were within ±5% of literature values.…”

Section: Methodsmentioning

confidence: 74%

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Thermal properties of sodium borosilicate glasses as a function of sulfur content

et al. 2020

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Sulfur trioxide (SO3) additions, up to 3.0 mass%, were systematically investigated for effects on the physical properties of sodium borosilicate glass melted in air, with a sulfur‐free composition of 50SiO2–10Al2O3–12B2O3–21Na2O–7CaO (mass%). Solubility measurements, using electron microscopy chemical analysis, determined the maximum loading to be ~1.2 mass% SO3. It was found that measured sulfur (here as sulfate) additions up to 1.18 mass% increased the glass transition temperature by 3%, thermal diffusivity by 11%, heat capacity by 10%, and thermal conductivity by 20%, and decreased the mass density by 1%. Structural analysis, performed with Raman spectroscopy, indicated that the borosilicate network polymerized with sulfur additions up to 3.0 mass%, presumably due to Na2O being required to charge compensate the ionic SO42- additions, thus becoming unavailable to form non‐bridging oxygen in the silicate network. It is postulated that this increased cross‐linking of the borosilicate backbone led to a structure with higher dimensionality and average bond energy. This increased the mean free paths and vibration frequency of the phonons, which resulted in the observed increase in thermal properties.

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Section: Discussionsupporting

confidence: 91%

Section: Resultssupporting

confidence: 85%

“…The specific heat capacity was calculated using the temperature rise of the measured specimen and the energy input of the laser pulse as shown in Equation ,

c_{p} = \frac{italicaAq}{m Δ T_{m}}

Section: Methodsmentioning

confidence: 74%

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Thermal properties of sodium borosilicate glasses as a function of sulfur content

et al. 2020

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“…Seven glasses were selected from a large database of potential Hanford waste glasses to represent the range of compositions likely to be produced in either the LAW or HLW vitrification plants: WTP LAW glasses with high soda (ORPLA20), intermediate soda (LAWA44 and ORPLD1), and lower soda (LAWB99) compositions; HLW glasses with high iron (HLW‐Ng‐Fe2), high alumina (HLW‐Al‐27), and intermediate (WTP‐C106) compositions. Because no waste glass thermal property reference standards exist, we selected two simulated Japanese HLW glasses (A and B in Table ) from a recent study by Sugawara et al in which careful C p measurements were made using multiple methods . Using both property reference standards, we repeated the measurements of the same glasses using our procedure to verify the results of our method.…”

Section: Methodsmentioning

confidence: 99%

“…While the thermal properties of glasses have been extensively studied, few studies of nuclear waste glasses have been conducted mainly because of the complex compositions of the waste glasses . The limited number of studies that have been published have reported significant uncertainties in the thermal properties because of difficulties involved in experimental measurements .…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of simulated Hanford waste glasses

et al. 2017

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The Hanford Tank Waste Treatment and Immobilization Plant will vitrify the mixed hazardous wastes generated from 45 years of plutonium production at the Hanford Site in Washington State. The molten glasses will be poured into stainless steel containers or canisters and subsequently cooled for storage and disposal. For appropriate facility design and operations to handle such highly energy‐consuming processes, knowledge of the material properties is required. The thermal properties (heat capacity, thermal diffusivity, and thermal conductivity) of representative high‐level and low‐activity waste glasses were studied as functions of temperature in the range of 200°C‐800°C (relevant to the cooling process). Simultaneous differential scanning calorimetry‐thermal gravimetry (DSC‐TGA), Xe‐flash diffusivity, pycnometry, and dilatometry were implemented. The study showed that simultaneous DSC‐TGA would be a reliable method for obtaining the heat capacity of various glasses in the temperature range of interest. Accurate thermal properties from this study were shown to provide a more realistic guideline for capacity and time constraints of the heat removal process when compared to the original conservative design‐basis engineering estimates. The estimates, though useful for design in the absence of measured physical properties, can now be supplanted and the measured thermal properties can be used in design verification activities.

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