Published online by Cambridge University Press: 03 September 2012
Drip tests designed to replicate the synergistic interactions between wasteglass, repository groundwater, water vapor, and sensitized 304L stainlesssteel in the potential Yucca Mountain Repository have been ongoing in ourlaboratory for over ten years. Results will be presented from three sets ofthese drip tests: two with actinide-doped glasses, and one with afully-radioactive glass. Periodic sampling of these tests have revealedtrends in actinide release behavior that are consistent with theirentrainment in colloidal material when as-cast glass is reacted. Resultsfrom vapor hydrated glass show that initially the actinides are completelydissolved in solution, but as the reaction proceeds, the actinides becomesuspended in solution. Sequential filtering and alpha spectroscopy ofcolloid-bearing leachate solutions indicate that more than 80% of theplutonium and americium are bound to particles that are captured by a 0.1 μmfilter, while less than 10% of the neptunium is stopped by a 0.1 μm filter.Analytical transmission electron microscopy has been used to examineparticles from leachate solutions and to identify several actinide-bearingphases which are responsible for the majority of actinide release duringglass corrosion.