Study on elemental distribution in the process of nuclear waste glass melting
EMSL Project ID
49174
Abstract
A large volume of low-activity waste (LAW) will be vitrified into borosilicate glass at the Hanford Tank Waste Treatment and Immobilization Plant. The LAW is typically an aqueous solution containing predominantly nitrates and nitrites with other salts/hydroxides. LAW glass feeds were prepared from a simulated liquid LAW and additives (boric acid, silica sand, etc.). Based on the current formulation of LAW glasses, we also designed a series of simplified sodium borosilicate glasses spiked with “problematic” elements such as Re (a nonradioactive surrogate of 99Tc, the primary volatile radionuclide), S, Cl, Cr, etc. Within the entire melting temperature range of ~300 – 1100°C, the partitioning and retention of those elements will be studied with different concentrations of nitrate, carbonate, and sulfate. The effects of different salts on elements partitioning into molten salts and the glass forming (borosilicate) melt in the batch-to-glass conversion (reactions) will be discussed. In order to analyze these extremely complicated batch reactions and investigate partitioning behaviors, elemental analysis will be necessary to profile the elemental distribution in micro-scale. Electron microprobe analysis (EMPA) and atom probe tomography (APT) are very powerful tools offering high-quality elemental distribution data, which will be decisive results for the reaction mechanism study. Those characterization methods will be instrumental in our efforts to understand the LAW glass melting process.
Project Details
Start Date
2015-10-26
End Date
2016-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members