F Reactor Cocooning Complete

Release Date: December 18, 2003

RICHLAND, WA-Cocooning has been completed at F Reactor, well ahead of the September 2004 Tri-Party Agreement milestone. Finishing the paperwork is all that remains for the interim safe storage of F Reactor to be declared officially complete.

"Meeting this milestone is another significant advancement in reducing risk to workers, the public and the environment," said Beth Bilson. "We're certainly on a roll - three cocooned and two more to be finished in the next two years is great cleanup progress." Bilson is Assistant Manager for the River Corridor at the U.S. Department of Energy's Richland Operations Office.

F Reactor is the third Hanford plutonium production reactor to be placed in interim safe storage - called cocooning - by the Bechtel Hanford-led Environmental Restoration Project team.

Cocooning involves demolishing the reactor building down to the three-foot-thick concrete shield walls surrounding the reactor core. All openings in the remaining structure are sealed and a new roof is installed.

Temperature and moisture sensors are used to remotely monitor conditions inside the sealed reactor building. Once every five years, workers will enter the structure to conduct inspections and make any needed repairs.

With the exception of building the new roof, most of the work involves demolition. "Demolition work is dangerous under the best of circumstances," said Mike Mihalic, Bechtel task lead for the cocooning project.

"When you add radioactive and hazardous materials to the mix, it becomes even more challenging. The fact that F Reactor and the two previously cocooned reactors were safely completed ahead of schedule and under budget is a testament to the team and the workers commitment to excellence," Mihalic said.

C Reactor cocooning was completed in 1998 and DR Reactor cocooning was completed in 2002. Some aspects of F Reactor cocooning were more challenging than the two previous reactor cocooning projects.

F Reactor operated from February 1945 to June 1965. When it was deactivated, all but three feet of water was removed from the 20-foot-deep spent fuel storage basin and workers filled the basin with river cobble and other debris. What remained was a radioactive sludge and, as it turned out, 17 spent fuel elements and some fragments, underneath 20 feet of fill material.

Knowing there might be fuel elements and other radioactive debris in the basin, workers spent nearly a year cleaning out the basin using a remotely controlled excavator.

A second challenge for the environmental restoration team was what to do about several species of bats that inhabited the reactor. Although not endangered, the bats are listed in the State of Washington's Priority Species List. Workers constructed a one-way door so the bats could exit the facility but not return. Eight commercial bat houses that can hold up to 100 bats each were installed around the reactor building to replace lost habitat.

Employees also had to work around a Great Horned Owl until her brood left the nest.

The last major piece of work in the cocooning project was to install the new roof. Thompson Mechanical installed the roofs on DR and F reactors. The experience they gained on DR Reactor allowed roof installation on F Reactor to proceed ahead of schedule. Roof installation was finished in August 2003, completing the physical work of cocooning at F Reactor.

Two additional reactor cocooning projects are under way. D Reactor is 90 percent complete and scheduled to be finished in 2004. H Reactor is 56 percent complete and scheduled to be finished in 2005. The cocooned reactors could remain in interim safe storage for up to 75 years.

"Hanford has made significant progress cleaning up the old reactors and associated water effluent sites," said Bechtel Hanford President Tom Logan. "Work is complete or underway on more than half of Hanford's nine surplus production reactors. In addition, nearly 50 percent of the contaminated soil has been moved away from the Columbia River," said Logan.

"That work represents significant progress toward DOE's goal of accelerated cleanup of the river corridor. And, cocooning of F Reactor marks completion of a major milestone for the ER Project team," he said.

"Additional funding provided by Congress in past years was instrumental in keeping the reactor cocooning project on track," said Logan. "Those funds helped save jobs and preserve technical expertise required for D and H reactor cocooning, which is underway now.

The U.S. Department of Energy's 586-square-mile Hanford Site is located in southeastern Washington state. Bechtel Hanford and subcontractors CH2M Hill Hanford and Eberline Services Hanford manage the Environmental Restoration Project for DOE.

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High Resolution Photo

Hanford's F Reactor was one of three constructed during the Manhattan Project to manufacture plutonium for World War II. Construction began December 1943. The reactor operated from February 1945 to June 1965. Reactor cocooning began in November 1997 and was completed in August 2003. (Photo dated July 12, 1965.)

High Resolution Photo

This photo taken in August 2003, shows all that remains of Hanford's F Reactor. Reactor cocooning was completed in August. It entails demolishing the reactor down to the three-foot-thick shield walls that surround the reactor core, sealing all openings and constructing a new roof.

High Resolution Photo High Resolution Photo

Several bat species roost in Hanford's abandoned buildings, including the surplus plutonium reactors. Before cocooning of F Reactor was complete, workers created alternate habitat for roosting Pallid bats, which are listed on the State of Washington's Priority Species List.