Workers at the Hanford Site’s Waste Treatment and Immobilization Plant, also known as the Vit Plant, have begun removing the first three of 18 temporary startup heaters, the Department of Energy announced on September 12. The startup heaters were used to raise the first of two 300-ton glass melters in the plant’s Low-Activity Waste Facility to its operating temperature of 2,100°F.
Once operational, the melters will be used to immobilize Hanford’s radioactive and chemical tank waste, turning it into a stable glass form through vitrification. About 56 million gallons of waste is stored in underground tanks at the site near Richland, Wash., the byproduct of defense-related plutonium production.
The process: Vit Plant workers began adding glass beads, or frit, to the melter in August, following a monthlong process of heating the melter to its operational temperature. Once a pool of molten glass was formed in the melter, crews were able to begin removing the startup heaters and initiating Joule heating, which passes electrical current through the molten glass to produce heat.
Once removed, the startup heaters will be replaced with bubblers, which circulate the molten glass using air to maintain a consistent mixture and temperature. The remaining startup heaters will be removed and replaced with bubblers after the final molten glass level is reached.
During Hanford’s direct-feed low-activity waste operations, tank waste will be heated inside the plant’s melters and mixed with glass-forming materials. The mixture then will be poured into stainless steel containers to cool before being disposed of in a specially engineered landfill on the Hanford Site called the Integrated Disposal Facility.
Transportation testing: According to the DOE, during the Vit Plant’s nearly yearlong cold commissioning and testing phase, Hanford Site contractor Washington River Protection Solutions will prepare for shipping vitrified radioactive waste by transporting containers of nonradioactive glass to an off-site disposal facility.
Using a specially designed truck and trailer, the containers of test glass will be transported to Chemical Waste Management, an industrial and hazardous waste landfill in Arlington, Ore., about 125 miles from Hanford. Eventually, the same truck and trailer will be used to ship vitrified radioactive waste from the Vit Plant to Hanford’s Integrated Disposal Facility.
“This is another achievement that brings us a step closer to immobilizing Hanford’s tank waste,” said Delmar Noyes, assistant manager for Hanford’s Tank Farms Project. “This process allows Hanford Site contractors to test their mission readiness and make any adjustments needed to procedures or processes before commissioning of the facility begins.”
During this testing phase, more than 350 containers will be filled with frit to begin with, and ultimately with tank waste simulants and frit to mimic the process that will be used during actual operations. Shipments to the off-site landfill during this period will range from once or twice a week, to as often as daily, the DOE said.