Study on elemental distribution in the process of nuclear waste glass melting
EMSL Project ID
49954
Abstract
The objective is to profile the distribution of particular elements in different stages of the glass melting process. Melting of nuclear waste glass is a complex process because there are over 20 different elements from the mixture of nuclear waste and glass forming and modifying additives, and large amounts of salts cause extensive gas evolving. The partitioning between different phases (molten salt and early glass forming melt) of some critical elements (radionuclides) is a key to understand the mechanism of volatile loss of those elements. We prepared samples by heating dried feed at different melting stages. The nuclear waste glass feeds were prepared by mixing low activity wastes (LAW) simulant (water solutions with high concentrations of nitrates, nitrites and other salts) and quartz, boric acid and other minerals. Samples at different melting stages (heated to different temperatures) were mounted in epoxy resin and polished. High quality elemental mapping is a powerful tool to get the elemental distribution in micro-scale, by which we can further profile the partitioning of elements at different temperatures during the melting. However, our Scanning Electron Microscopy with X-ray microanalysis (SEM-EDS) units at APEL are not capable to analyze light elements especially boron and nitrogen and electron probe microanalysis (EPMA) has been out of work for a while. Preliminary secondary ion mass spectroscopy (SIMS) results have successfully shown the capability to obtain mapping. In order to move this study forward, we request ~ 250 hours of SIMS time (located in 1200 EMSL) in FY 2017-18.
Project Details
Start Date
2017-06-22
End Date
2017-09-30
Status
Closed
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Principal Investigator
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