From start to finish, the decontamination and demolition of Hanford's 308 Building just north of Richland may have required the most work of any building yet at Hanford in the area along the Columbia River.
But Wednesday, Washington Closure Hanford announced the building had been reduced to rubble.
The building was one of the larger ones along the Columbia River at 71,000 square feet. But it wasn't the demolition with heavy equipment that was difficult, but what had to be addressed inside that made the project a challenge.
The building housed 52 glove boxes where workers would look through windows and reach into ports with attached gloves to do work with radioactive materials. Most glove boxes were 8 to 12 feet long and weighed about 1,200 pounds.
In addition, the glove boxes and exhaust system were heavily contaminated with plutonium.
"It's flighty," and contamination can spread easily, said Gary Snow, director of Washington Closure's decontamination and demolition organization.
The building, called the Plutonium Fabrication Pilot Plant and later the Fuels Development Laboratory, was built in 1960 for the development of reactor fuel that contained plutonium. Later that decade it began to be used for development or testing of many exotic fuels, with more than 2,000 fuel configurations produced before 1976, Snow said.
It also was used to prepare and test fuel for Hanford's Fast Flux Test Facility.
The building was known for the high-bay, called the 308A Building, added in 1971 that would cover one of the six small test reactors housed at different times in the 300 Area just north of Richland. Those reactors were in addition to the nine larger reactors along the Columbia River previously used to produce weapons plutonium.
The Training, Research, Isotopes, General Atomics, or TRIGA, reactor in the 308A buildings was used in a program to look for defects in fuel elements and fuel jackets.
The 308A Building came down in 2011, although the TRIGA reactor remains and is covered with shielding blocks.
Preparations for taking down the main building started with decontamination efforts. Some equipment contaminated in a fire and explosion in 1965 had been removed earlier and stored in central Hanford.
Rather than cut up glove boxes to prepare the building for demolition, Washington Closure chose to pull them out intact and then sendthem to Perma-Fix in Richland to be cut into smaller pieces and to be packaged in containers.
Some could be disposed of as low-level radioactive waste at Hanford's Environmental Restoration Disposal Facility and others have enough plutonium contamination to require them to be shipped to the Waste Isolation Pilot Plant in New Mexico for disposal.
Most of the glove boxes were disconnected, cleaned and wrapped before they were removed. Those on the second floor were placed on a cart and rolled to a loading dock to be lifted down with a crane.
The first glove boxes were removed in late 2008, and demolition of the 308 Building started two months ago.
Phoenix Enterprises NW of Richland has been awarded a subcontract to remove the TRIGA reactor and the only other test reactor remaining at the Hanford 300 Area, the Plutonium Recycle Test Reactor, which sat under the iconic dome at Hanford just north of Richland.
Phoenix is expected to remove the 350-ton Plutonium Recycle Test Reactor this summer. The dome was removed early last year.
By late summer or early fall, Phoenix should be ready to remove the 250-ton TRIGA reactor. Both reactors will be shipped to the Environmental Restoration Disposal Facility in central Hanford.
The Department of Energy's goal is to complete most environmental cleanup at Hanford along the Columbia River by 2015, and demolition of the 308 Building is a major step toward that, Snow said.
-- Annette Cary: 582-1533; firstname.lastname@example.org