Crews at the Hanford Vitrification Plant have begun a series of complicated cooling panel installations in the low-activity waste vitrification (LAW) facility. Bechtel National Inc., Richland, Wash., is designing and building the facility, reported to be world’s largest radioactive waste treatment plant, for the U.S. Department of Energy at the Hanford site in southeastern Washington.
The $12.2 billion waste treatment and immobilization plant (WTP), also known as the vit plant, will immobilize radioactive liquid waste currently stored in 177 underground tanks using a process called “vitrification.” Vitrification involves blending the waste with molten glass and heating it to high temperatures. The mixture then is poured into stainless steel canisters for permanent storage. In this glass form, the waste is stable and impervious to the environment, and its radioactivity will dissipate over hundreds to thousands of years.
The cooling panels are being installed in the area of the facility where the 2,100°F (1,149°C) waste-glass mixture will be poured into the stainless steel containers. The panels will absorb the extreme heat emitted from the mixture, helping to keep the pour area at approximately 150°F (66°C). This temperature allows the containers to cool enough to be transported out of the facility and maintains the integrity of both the equipment and surrounding concrete, says Bechtel.
The cooling panels are specially treated to absorb heat and must be handled with care, as even the natural oils from human hands can compromise the treatment coating. During installation, the panels are covered in a polyurethane protective layer that will be removed, and workers must wear white cotton gloves.
The panels, which measure less than 0.75" thick, span a range of sizes from 4' wide a few feet long to panels the same width and 16' long. To keep them from bending during installation, they are fitted on custom-built installation frames. The installation process, which involves 60 panels that cover 2,900 ft2 in total, is expected to be complete in early 2011.
“Once the panels are installed, workers will connect piping that will transport chilled water to the panels," says Wes Hoover, assistant area superintendent for the LAW facility.
The WTP will cover 65 acres with four nuclear facilities - pretreatment, low-activity waste vitrification, high-level waste vitrification and analytical laboratory - as well as operations and maintenance buildings, utilities and office space. Construction began in 2001, and the plant will be operational in 2019.