The Plutonium Finishing Plant is another step closer to being torn down after decades of work to clean out the heavily contaminated facility at the Hanford Site in Washington state.
This week the Department of Energy announced that both of the 12-foot-tall glove boxes in the plant’s main processing building had been cut up, removed, and packed into boxes for eventual disposal at the Waste Isolation Pilot Plant in New Mexico.
They were the highest-hazard glove boxes in the main building of the plant. DOE and contractor CH2M Hill Plateau Remediation Co. have been working toward the start of demolition of the plant this spring to help meet a Tri-Party Agreement milestone to have the facility down to slab on grade by the end of the fiscal year.
Work has slowed some at the plant to ensure that employees are focused on safety and that not too much high-hazard work is undertaken simultaneously after worker and equipment contamination incidents during cleanup operations on the most challenging projects at the plant once used to prepare plutonium for use in nuclear weapons. If DOE is unable to meet a milestone it notifies regulators, and no notification has been sent. CH2M Hill says that demolition will have started before the end of the fiscal year.
“Removing the glove boxes brings the Department of Energy and our contractor a significant step closer to being ready to start demolishing the plant,” said Tom Teynor, project director for the DOE Richland Operations Office, in a statement.
Cleanup operations on the plant date to the 1990s when efforts began to stabilize plutonium in a liquid solution that remained after the end of the Cold War. In recent years work has focused on cleaning out and removing contaminated equipment and fixtures, including the plant’s 238 glove boxes.
CH2M Hill workers got to the two oversize glove boxes in June 2015. They were too large and too contaminated to be removed from the building in one piece. Workers finished size reduction and removal of HC-9B in August and finished removal of HA-9A this month. Both measured 8 feet wide and 3 feet deep.
Workers would conduct work at three operating levels at the boxes, converting the plutonium feed received at the plant into metal pucks or oxide powders.
Work on the glove boxes was challenging not only because of their size, but the amount of plutonium contamination within them, said Tom Bratvold, CH2M Hill acting vice president at the plant. Radiation levels were high, and workers were innovative in their application of lead blankets to provide shielding, he said. “They would almost daily reconfigure their shield walls – their blanket arrays – to minimize exposure,” he said.
Because the plutonium, particularly the plutonium fluoride remaining in the glove boxes, was easily airborne workers wore air-filled protective suits that have a higher pressure within the suits than outside them to help prevent worker contamination. The suits, which use supplied-air respirators, are reserved for some of the most hazardous work at the plant.
“This was some of the most hazardous work performed at the site and right up there with the most hazardous work performed at any of the DOE nuclear weapons production sites,” Teynor said.
The plant’s main building still has 13 smaller glove boxes that have been cleaned out, packaged, and staged for removal immediately before and during demolition. No more glove boxes in the main plant still must be cleaned out or removed in preparation for demolition, but “there are still a number of different aspects of the facility we need to attend to,” Bratvold said.
Work remaining in the main building includes addressing asbestos and other hazardous materials, removing duct work, and isolating and removing a vacuum transfer system that was used to move plutonium-rich material.
Removal of the HA-9A and HC-9B glove boxes was one of three high-hazard projects left to the end of cleanout of the plant. High-hazard work still must be done on two additions to the main processing area of the plant: the Plutonium Reclamation Facility and the Americium Recovery Facility.
Personnel recently completed grouting the floor of the canyon in the Plutonium Reclamation Facility. Next, workers will decontaminate the strong backs, or racks, that held the pencil tanks that once hung on the canyon walls. They also will decontaminate the canyon walls. The Plutonium Reclamation Facility has the last four glove boxes in the Plutonium Finishing Plant that still must be prepared for demolition. They are integral to the plant and its ventilation system, and work on the glove boxes will not be done while the ventilation system is still needed for work in the canyon.
Work at the Americium Reclamation Facility must be done by workers wearing the air-filled protective suits and the crew that size-reduced the glove boxes in the main building will be assigned to the work. Chemical tanks there must be prepared for removal.
