(18g) Millimeter-Wave High and Low Level Activity Waste Glass Research

Millimeter-wave (MMW) technologies are being co-developed by SRNL, MIT, and PNNL to provide robust on-line monitoring tools for high temperature vitrification of the nuclear wastes at the Defense Waste Processing Facility (DWPF) at the Savannah River Site and the Waste Treatment Plant (WTP) under construction at Hanford. MMW passive and active radiometry techniques are being developed to measure surface and melt pool temperatures, surface emissivity, salt and foam layer formation, surface fluctuations, and melt pour rates. MMW prototypes have been built at MIT and SRNL that use a 137 GHz heterodyne receiver with wavelengths long enough to penetrate the optical obscure views of a slurry-fed melter like the one used at DWPF. The wavelengths are still short enough to provide spatially resolved measurements and profiles. An overview of the MMW research done to date will be presented.