Physical properties of an alumino-silicate waste form for cesium and strontium

Nuclear fuel reprocessing will be required to sustain nuclear power as a baseload energy supplier for the world. New reprocessing schemes offer an opportunity to develop a better strategy for recycling elements in the fuel and preparing stable waste forms. Advanced strategies could create a waste stream of cesium, strontium, rubidium, and barium. Some physical properties of a waste form containing these elements sintered into bentonite clay were evaluated. We prepared samples loaded to 27% by mass to a density of approximately 3 g/cm(3). Sintering temperatures of up to 1000 degrees C did not result in volatility of cesium. Instead, the crystallinity noticeably increased in the waste form as temperatures increased from 600 to 1000 degrees C. Assemblages of silicates were formed, Significant water evolved at approximately 600 degrees C but no other gases were generated at higher temperatures. (C) 2009 Elsevier B.V. All rights reserved.