A small dc arc melter was designed and constructed to run bench-scale investigations on various aspects of development for high-temperature (1,500-1,800°C) proccssing of simulatcd transuranic-contaminatcd waste and soil located at the Radioactive Waste Management Complex (RWMC). Several recent system design and treatment studies have shown that high-tempcrature melting is the preferred treatment. The small arc melter is needed to establish techniques and procedures (with surrogates) prior to using a similar melter with the transuranic-contaminatcd wastes in appropriate facilities at the site. This report documents the dcsign and construction, starting and heating procedures, and tests evaluating the mclter's ability to process several waste types stored at the RWMC. lt is found that a thin graphite strip provides reliable starting with initial high current capability for partially melting the soil/waste mixture. The heating procedure includes (1) the initial high current-low voltage mode, (2) a low current-high voltage mode that " commences after some slag has tbrmed and arcing dominates ovcr the receding graphite conduction path, and (3) a predominantly Joule heating mode during which thc currcnt can bc increased within the limits to maintain relatively quiescent operation. Scvcral experiments involving the melting of simulated wastes arc discussed. Energy balancc, slag tcmpcraturc, and electrode wear mcasurements are presented. Recommendations for further refinements to enhance its processing capabilities are identified. Future studies anticipated with the arc melter include waste form processing development; dissolution, retention, volatilization, and collection for transuranic and low-levcl radionuclides, as well as high vapor prcssure metals; clcctrode material development to minimize corrosion and erosion; refractory corrosion and/or skull formation effects; crucible or melter geometry; metal oxidation; and desirable melt reduction/oxidation (redox) conditions.

This report describes a simple automated system for measuring interfacial tension using the pendant or sessile drop method. The size and shape of a transparent or opaque drop of one fluid immersed in a second, transparent, fluid is recorded with a CCD video camera and digitized and stored by a computer-controlled system. Custom software determines various droplet shape factors and computes the interfacial tension. A limited number of video frames can be stored on disc, or longer runs can be stored on video tape for later digitization. Alternately, only the shape factor and interfacial tension data are stored to reduce demands on the storage medium.

No abstract

No abstract

This report describes the INEL Research Center (IRC) arc melter facility and its recent modifications. The arc melter can now be used to study volatilization of toxic and high vapor ' pressure metals and the effects of reducing and oxidizing (redox) states in the melt. The modifications include adding an auger feeder, a gas flow control and monitoring system, an offgas sampling and exhaust system, and a baghouse filter system, as well as improving the electrode drive, slag sampling system, temperature measurement and video monitoring and recording methods, and oxidation lance.