Conversion of Nuclear Waste to Molten Glass: Cold‐Cap Reactions in Crucible Tests |
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| Authors: | Kai Xu Pavel Hrma Jarrett A Rice Michael J Schweiger Brian J Riley Nicole R Overman Albert A Kruger |
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| Affiliation: | 1. Pacific Northwest National Laboratory, Richland, Washington;2. U.S. Department of Energy, Office of River Protection, Richland, Washington |
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| Abstract: | The feed‐to‐glass conversion, which comprises complex chemical reactions and phase transitions, occurs in the cold cap during nuclear waste vitrification. To investigate the conversion process, we analyzed heat‐treated samples of a simulated high‐level waste feed using X‐ray diffraction, electron probe microanalysis, leaching tests, and residual anion analysis. Feed dehydration, gas evolution, and borate phase formation occurred at temperatures below 700°C before the emerging glass‐forming melt was completely connected. Above 700°C, intermediate aluminosilicate phases and quartz particles gradually dissolved in the continuous borosilicate melt, which expanded with transient foam. Knowledge of the chemistry and physics of feed‐to‐glass conversion will help us control the conversion path by changing the melter feed makeup to maximize the glass production rate. |
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| Keywords: | nuclear waste glass reaction path |
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