As part of the waste treatment process, workers at Bechtel’s Hanford Vit Plant are installing components in a key safety system for the Low-Activity Waste (LAW) Vitrification Facility glass melters, the off-gas treatment system.
The off-gas treatment system is used to protect workers, the public, and the environment by removing contaminants from the melter exhaust.
The LAW Facility has two melters that will be used to solidify the bulk of the 56 million gallons of liquid radioactive waste stored in underground tanks at Hanford. Each melter will have a wet electrostatic precipitator (WESP) as part of its primary off-gas treatment system.
As part of the assembly process, workers are installing electrodes into collector bundles, which are internal components in the WESP.
Each WESP vessel is about 21 feet tall by 10 feet in diameter. The stainless steel vessels have 123 collector tubes running lengthwise with a seven-foot electrode running down the center of each collector tube.
The filtering process works by statically charging the inside of the collector tubes, or plates, which attract particulates from the humid off-gas flowing over the plates. The collector plates are cleaned periodically using a flushed-water system, which is treated elsewhere.
Once all the electrodes are assembled in the collector bundles, the bundle assemblies will be installed in the WESP vessels later this fall.
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A Vit Plant worker adjusts one of the newly installed electrodes in the collector bundle, part of the wet electrostatic precipitators, a primary component in the off-gas treatment system for the Low-Activity Waste Vitrification Facility melters.
The stainless steel electrodes in the wet electrostatic precipitators are electrically charged to remove contaminants in the melter off-gas. The precipitators are part of a safety system that protects workers and the public from toxic off-gas generated as part of the waste solidification process.
There are two wet electrostatic precipitators in the Low-Activity Waste Vitrification Facility, one for each waste/glass melter. Pictured, a Vit Plant worker inserts one of 123, 7-foot-long, stainless steel electrodes into the wet electrostatic precipitator collector bundle.