Hydrothermal Studies of Simulated Defense Waste Glass Plus Basalt

Abstract

AbstractThe Basalt Waste Isolation Project (BWIP) is conducted for the U.S. Department of Energy (DOE) by Rockwell Hanford Operations (Rockwell). The BWIP has undertaken an experimental program to test the behavior of defense waste glass under conditions relevant to a repository in basalt. Three autoclave experiments utilizing a nonradioactive simulated waste glass (Savannah River Laboratory (SRL) Type 131/TDS-3A) have been completed. Monolithic discs and crushed glass particles were reacted with crushed basalt and synthetic basalt groundwater for ∼1 yr at temperatures of 90 °C to 150 °C. The crushed qlass proved considerably more reactive than the monoliths at similar temperatures. Raising the temperature from 90 °C to 150 °C produced a striking increase in the extent of glass alteration. At 150 °C, essentially all of the boron and most of the sodium in the glass particles were released. The major reaction products in all three experiments were smectite clay and zeolites. The two tests utilizing crushed glass also yielded analcime. Nickel, cesium, and strontium, important elements in defense waste, were released from the glass in small quantities. The nickel was incorporated into the clay, while the cesium was incorporated into the analcime.