Dr. John S. McCloy, Professor and Director of the School of Mechanical & Materials Engineering and Lindholm Endowed Chair in Materials Engineering at Washington State University will give a seminar titled "Structure and Chemistry of F-, Cl-, and SO42- in Crystals, Melts, and Glasses: Nuclear Waste Vitrification and Other Applications" to the interested faculty and students at Discovery Park.

Abstract

The modern world requires more and more energy to power computers, vehicles, and everything in between. One globally important energy source is nuclear power. The state of Washington has a long history with nuclear technology dating back to the Manhattan project. Activities at the Hanford site in southeastern Washington state from the 1940s-1980s resulted in a legacy ~56 million gallons of radioactive and highly complex chemical waste, now currently in remediation by the US Department of Energy. Vitrification in borosilicate glass is the accepted baseline immobilization technology, and glass compositions are designed to maximize waste loading and glass production rate, while maintaining predictable properties and processing envelopes. Several physical phenomena limit waste loading in Hanford glass, including formation of a molten salt layer containing alkali, sulfate, and halide, which is deleterious to melter operations and waste form durability.

In addition to nuclear waste vitrification, anions in silicate melts, including F-, Cl-, and SO42-, play a vital role in volcanism, optical materials, bioglasses, molten salt reactors, and electrowinning. Structure and crystal chemistry of sulfate, fluoride, and chloride anions will be discussed through a study of 1) the structure in pure ionic glasses and as additives to oxide glasses, 2) the structure in molten salt liquids, 3) crystallization in multicomponent melts and glasses, and 4) insight from mineralogy. Understanding and predicting these structures in glasses and liquids gives insight into salt formation, phase separation, and crystallization phenomena.

Bio

Dr. John S. McCloy is Professor and current Director (Department Head) of the School of Mechanical & Materials Engineering and Lindholm Endowed Chair in Materials Engineering at Washington State University (WSU) in Pullman, WA. His professional career includes stints in academia (11 y), national laboratory (5 y), and industry (10 y) – a professor at WSU since 2013, a research scientist at Pacific Northwest National Laboratory (where he retains a joint appointment as Chief Scientist), and a Raytheon multi-disciplined engineer in Tucson. At WSU, he leads the Nuclear, Optical, Magnetic, & Electronic (NOME) Materials Lab and the Crystals and SemiConductors (CASC) groups, both within the Institute of Materials Research (IMR). Together these scientists and engineers develop materials solutions for energy, environment, and security applications. Over his career, he has worked on diverse engineering problems, including cryogenics, composite structures, telescopes, optical ceramics, magnetic nanoparticles, ancient materials technologies, nuclear fuels, single crystal growth, and glass development for immobilization of radioactive waste. His main interests in materials lie within crystal chemistry and solid-state physics, as well as advanced characterization techniques. He holds a BS degree in Materials Science & Engineering (MSE) from the Massachusetts Institute of Technology, an MA in Cultural Anthropology and an MS and PhD in MSE from the University of Arizona. He is an author or co-author of over 200 journal articles, plus over 50 more book chapters, conference proceedings, public reports, and patents. He is a Fellow of the American Ceramic Society, a member of the Washington State Academy of Sciences, a senior member of SPIE, and a Fulbright Scholar.