Hanford workers have pulled the largest plutonium-tainted glovebox yet out of the Plutonium Finishing Plant.
The two-story glovebox, weighing 10 tons and stretching almost the width of the room where it stood, needed to come out of the plant to allow gloveboxes in the room behind it to be removed.
"It was absolutely wonderful to watch," said Jerry Long, vice president of the Plutonium Finishing Plant closure project for Department of Energy contractor CH2M Hill Plateau Remediation Co.
DOE has called the Plutonium Finishing Plant the most complex and hazardous facility at Hanford. It operated for 40 years starting in 1949, taking plutonium that had been chemically separated from Hanford's irradiated fuel rods and producing metal buttons the size of hockey pucks.
The buttons were shipped off Hanford to be fabricated for use in the nation's nuclear weapons program.
Now the plant is being prepared for demolition. DOE has a legal deadline under the Tri-Party Agreement to have the plant torn down to slab on grade by fall 2016 and would like to have it torn down a year earlier.
Some 177, or about 76 percent, of the gloveboxes have been removed. But work started with smaller and less-complex gloveboxes to help workers gain experience, leaving challenging work ahead.
The gloveboxes, which had leaded glass windows and portals with heavy gloves attached, protected workers as they reached into the boxes with their hands in the gloves to perform work with radioactive material.
The two-story glovebox just removed "is one of the most complex gloveboxes we have worked on to date," said Larry Romine, DOE project director for the plant, in a statement.
It was part of the Remote Mechanical A Line and was used for plutonium storage, Long said.
After the large glovebox was disconnected from electrical and ventilation systems, and decontaminated to the extent possible, workers installed steel rods inside it to be used for lifting the box.
Then the 240 bolts that attached the top story of the stainless steel box to the bottom story were cut.
The glovebox then was encased in a double layer of yellow plastic sleeves to contain radioactive contamination, with first one end and then another to fit the plastic around it.
Then steel covers were placed over each piece and sealed before the upper and lower stories of the glovebox were removed separately.
"It was something else," Long said. "Workers had near-flawless execution."
Workers had practiced on a mockup in an uncontaminated building starting in January with a wooden box built to match the glovebox's dimensions, if not its weight.
Two cranes were purchased for the project, and they were assembled at the mockup for several dry runs, then taken apart and reassembled in the close quarters of the Plutonium Finishing Plant that held the real and highly contaminated glovebox. The glovebox is 16 feet long.
The two pieces of the glovebox will be moved to Perma-Fix Northwest in Richland to be taken apart. Some parts will have enough plutonium contamination remaining that they will need to be packaged and shipped for disposal to the Waste Isolation Pilot Plant, a national repository in New Mexico.
Other parts may be less contaminated and can be disposed of as low-level radioactive waste at the Environmental Restoration Disposal Facility in central Hanford.
More large gloveboxes remain among the 55 yet to be removed. In addition, workers also have other high-contamination work remaining to prepare the plant for demolition. The plant still has pencil tanks, the Americium Recovery Facility, ventilation ducting, the process vacuum line and the process transfer lines.
-- Annette Cary: 582-1533; firstname.lastname@example.org