Work has begun to dig up the waste burial grounds around H Reactor, a relic of the Cold War near the Columbia River at the Hanford nuclear reservation.
The start of work complies with a legally binding Tri-Party Agreement deadline to begin cleanup of the grounds by Oct. 31. H Reactor irradiated fuel to produce plutonium for the nation’s nuclear weapons program, and tested processes and equipment. Much of the waste from the reactor was disposed of in unlined trenches, starting during the reactor’s construction in 1948 and continuing through its closure in 1965.
To meet environmental standards, the U.S. Department of Energy expects to retrieve 276,000 tons of waste from sites near the reactor and river. The work is being done by Federal Engineers & Constructors under a $9 million subcontract awarded by Washington Closure Hanford, which holds the DOE contract for Hanford cleanup along the Columbia.
With at least some cleanup work done at burial grounds near seven other reactors, workers have an idea of what to expect. They will dig up waste and soil contaminated with radioactive isotopes and hazardous chemicals, which could include lead, asbestos, mercury, PCBs and acid. Items could include reactor hardware, process equipment and waste, laboratory equipment and waste, metals, and construction debris.
Thorough records of what was disposed of in burial grounds near the reactor were not kept.
But “we’re ready to safely handle any anomalies we may encounter or items not on existing inventory logs,” said Mark Buckmaster, project manager for Washington Closure.
That includes being prepared to find pieces of irradiated fuel which will be too radioactively hot for workers to approach. The first pieces of spent fuel found when excavation of reactor burial grounds began were a surprise, since fuel was supposed to be carefully inventoried. But Hanford workers have found about 66 whole and partial fuel pieces. The pieces, as long as 8 inches, have radiation levels up to 200,000 times the exposure limit set by the Department of Energy, according to the Washington State Department of Ecology, a Hanford regulator.
To protect workers, the pieces are identified and handled by remotely operated equipment.
Most of the debris and contaminated soil to be unearthed near H Reactor will be sent to the Environmental Restoration Disposal Facility, a lined landfill in central Hanford for low-level radioactive waste. Any fuel pieces will require disposal at a federal repository, likely Yucca Mountain, Nev.
With work that started this week to dig up the clean soil above the H Reactor burial grounds, DOE is working on retrieval of waste in two reactor areas – the 100 H Area, and the 100 D and DR Area.
“We’re happy they are working on two at the same time,” said John Price, of the Department of Ecology. “The concurrent work should allow DOE to increase the rate of waste being shipped.”
DOE is required by the Tri-Party Agreement to have the first burial ground near the H Reactor excavated by the end of 2009, three excavated by the end of 2010 and all five by the end of 2011.