This paper describes preliminary results from the first demonstration of the Transportable Vitrification System (TVS) on actual mixed waste. The TVS is a fully integrated, transportable system for the treatment of mixed and low-level radioactive wastes. The demonstration was conducted at Oak Ridge's East Tennessee Technology Park (ETTP), formerly known as the K-25 site. The purpose of the demonstration was to show that mixed wastes could be vitrified safely on a 'field' scale using joule-heated melter technology and obtain information on system performance, waste form durability, air emissions, and costs.
The Transportable Vitrification System (TVS) is a large scale, fully integrated, vitrification system for the treatment of low-level and mixed wastes in the form of sludges, soils, incinerator ash, and many other waste streams. It was demonstrated on surrogate waste at Clemson University and at the Oak Ridge Reservation (ORR) prior to treating actual mixed waste. Treatment of a combination of dried B and C Pond sludge and CNF sludge was successfully demonstrated at ORR in 1997. The demonstration produced 7,616 kg of glass from 7,328 kg of mixed wastes with a 60% reduction in volume. Glass formulations for the wastes treated were developed using a combination of laboratory crucible studies with the actual wastes and small melter studies at Clemson with both surrogate and actual wastes. Initial characterization of the B and C Pond sludge had not shown the presence of carbon or fluoride, which required a modified glass formulation be developed to maintain proper glass redox and viscosity. The CNF sludge challenges the glass formulations due to high levels of phosphate and iron. The demonstration was delayed several times by permitting problems, a glass leak, and electrical problems. The demonstration showed that the two wastes could be successfully vitrified, although the design glass production rate was not achieved. The glass produced met the Universal Treatment Standards and the emissions from the TVS were well within the allowable permit limits.
The Transportable Vitrification System (TVS) is a large-scale, fully-integrated, transportable, vitrification system for the treatment of low-level nuclear and mixed wastes in the form of sludges, soils, incinerator ash, and similar waste streams. The TVS was built to demonstrate the vitrification of actual mixed waste at U.S. Department of Energy (DOE) sites. Currently, Westinghouse Savannah River Company (WSRC) is working with Lockheed Martin Energy Systems (LMES) to apply field scale vitrification to actual mixed waste at Oak Ridge Reservation's (ORR) K-25 Site. Prior to the application of the TVS to actual mixed waste it was tested on simulated K-25 B and C Pond waste at Clemson University. This paper describes the results of that testing and preparations for the demonstration on actual mixed waste.
The US DOE through the Mixed Waste Integrated Program, has identified a need to move mixed waste vitrification technology from the laboratory to the field as rapidly as possible. A great deal of work over the last few years has shown the feasibility of immobilizing selected hazardous waste streams in a vitrified product. Lab-scale work has been extended to pilot-scale tests, usually with surrogates of the actual waste. DOE felt that the technology was mature enough to allow demonstration in the field, on actual wastes, with units that would be prototypic of full sized waste treatment equipment. To this end, DOE's Office of Technology Development sponsored the Westinghouse Savannah River Company (WSRC) to specify, procure, test, and operate a field scale demonstration using mobile equipment. Oak Ridge Reservation was chosen as the initial location for the field demonstration and Martin Marietta Reservation was chosen as the initial location for the field demonstration and Martin Marietta Energy Systems (MMES) tasked with all permitting, site preparation, and field support activities. During September 1993, WSRC used a ''Vendor Forum'' to solicit preliminary proposals for the Transportable Vitrification System (TVS). A number of quality proposals were received and evaluated. A vendor was selected and detailed negotiations were completed in August 1994, at which time a contract was signed for the TVS. In parallel, WSRC opened a dialogue with MMES to explore candidate waste streams at the Oak Ridge Reservation for the first TVS vitrification campaign. After some preliminary work, a group of waste water sludges were selected. The first of these to be demonstrated with the TVS will be the West End Treatment Facility (WETF) sludge. This paper describes the development of the specification for the TVS, the design and construction activities to date, and ongoing efforts for permitting and site support. The schedule for field application is also discussed.
Two highly variable mixed (radioactive and hazardous) waste sludges were simultaneously vitrified in an EnVitCo Transportable Vitrification System (TVS) deployed at the Oak Ridge Reservation. The TVS was the result of a cooperative effort between the Westinghouse Savannah River Company and EnVitCo to design and build a transportable melter capable of vitrifying a variety of mixed low level wastes. The two waste streams for the demonstration were the dried B and C Pond sludges at the K-25 site and waste water sludge produced in the Central Neutralization Facility from treatment of incinerator blowdown. Large variations occurred in the sodium, calcium, silicon, phosphorus, fluorine and iron content of the co- blended waste sludges: these elements have a significant effect on the process ability and performance of the final glass product. The waste sludges were highly reduced due to organics added during processing, coal-pile runoff (coal and sulfides), and other organics, including wood chips. A batch-by-batch process control model was developed to control glass viscosity, liquidus, and reduction/oxidation, assuming that the melter behaved as a Continuously Stirred Tank Reactor.
The stabilization and disposal of mixed wastes, which contain both hazardous and radioactive materials, is a significant waste management challenge to the DOE complex.
Surrogate Oak Ridge Reservation West End Treatment Facility (WETF) sludge was vitrified in a pilot-scale EnVitCo melter at the Clemson University Environmental Systems Engineering Department (ESED) Vitrification Facility. Although much smaller than the Transportable Vitrification System (TVS) melter, this melter is similar in design to the one in the TVS. The TVS was built by EnVitCo for the Savannah River Technology Center (SRTC) for the treatment of low level and mixed wastes. A total of three tests were done by ESED personnel with guidance from SRTC TVS personnel. The purpose of these tests was to determine what problems might occur during the vitrification of WETF sludge feed in the TVS. The demonstration was successfully completed and the glasses produced passed the TCLP tests for all the hazardous waste components (Ba, Cd, Cr, Pb, and Ni). An overview of these tests and experimental results on glass container testing, glass pouring, glass product characterization, electrode and refractory wear, and offgas composition and particulate measurements will be given.
The Transportable Vitrification System (TVS) was a large-scale vitrification system for the treatment of mixed wastes. The wastes contained both hazardous and radioactive materials in the form of sludge, soil, and ash. The TVS was developed to be moved to various United States Department of Energy (DOE) facilities to vitrify mixed waste as needed. The TVS consists of four primary modules: (1) Waste and Additive Materials Processing Module; (2) Melter Module; (3) Emissions Control Module; and (4) Control and Services Module. The TVS was demonstrated at the East Tennessee Technology Park (ETTP) during September and October of 1997. During this period, approximately 16,000 pounds of actual mixed waste was processed, producing over 17,000 pounds of glass. After the demonstration was complete it was determined that it was more expensive to use the TVS unit to treat and dispose of mixed waste than to direct bury this waste in Utah permitted facility. Thus, DOE had to perform a Resource Conservation and Recovery Act (RCRA) closure of the facility and find a reuse for as much of the equipment as possible. This paper will focus on the following items associated with this successful RCRA closure project: TVS site closure design and implementation; characterization activities focused on waste disposition; pollution prevention through reuse; waste minimization efforts to reduce mixed waste to be disposed; and lessons learned that would be integrated in future projects of this magnitude.
The Mixed Waste Focus Area (MWFA) has chartered the Savannah River Technology Center (SRTC) to design and fabricate a Transportable Vitrification System (TVS) to demonstrate treatment of Low-Level Mixed Waste (LLMW). This system will be used to demonstrate the feasibility of vitrification on several LLMW streams. The first stream to be demonstrated will be the Oak Ridge Reservation (ORR) K-25 B & C Pond sludge. Before the demonstrations in the TVS can take place, a surrogate sludge vitrification demonstration had to be performed in the EV-16 melter located at the DOE Industrial Center for Vitrification Research (Center) at the Environmental Systems Engineering Department at Clemson University. During the demonstration at the Center, a 50 wt% B & C sludge glass composition was tested to determine any processing problems. A total of 1510 pounds (686 kg) of glass were produced from 9328 pounds (4240 kg) of surrogate feed. The resulting glass product was homogeneous and very durable.
