The Hanford Advisory Board is recommending that the Department of Energy take a conservative approach as it prepares to make plans to clean up the innermost 10 square miles of the Hanford nuclear reservation.
Unlike much of the rest of the 586 square miles of Hanford, the inner 10 square miles is expected to be off limits to the public even after active environmental cleanup concludes.
The land at the center of Hanford was used during weapons plutonium production to chemically process irradiated fuel and dispose of waste. Most of Hanford’s major production and waste disposal facilities, except those located in the area along the Columbia River, are clustered there.
“A lot of hard decisions are left to come,” said board member Shelley Cimon, as the advisory board discussed the issue at its Richland meeting last week.
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Central Hanford includes burial grounds with 42 miles of trenches, some of them over ponds used for waste disposal, she said. The PUREX tunnels are there, with high level radioactive waste sealed inside. Other waste was disposed of in underground caissons, she said. The area also has contaminated soil under waste storage tanks that have leaked.
Cleanup of the innermost area could be a decade or more in the future. But as much of the work to clean up land along the Columbia River at Hanford is being completed, DOE and its regulators are preparing to make plans for cleanup of the inner area. Officials want plans in place when the Hanford budget allows work to be done there.
DOE has come up with some tentative guidelines for the start of planning. Along with the Environmental Protection Agency and Washington’s Department of Ecology, DOE has discussed the guidelines with the Hanford Advisory Board over several months and asked for input.
The development of guidelines is commendable, the advisory board said in a letter sent late last week to the three agencies. But the board is concerned that the proposed guidelines do not fully characterize, quantify or address the risk to future generations.
“These guidelines underestimate the potential for failure in cleanup, and they ignore the real, long-term costs of institutional controls,” the board said in the letter. Institutional controls are the means — from fences to deed restrictions — by which DOE would keep the public out of areas where hazardous materials may remain far into the future.
The cleanup standard planned for the central 10 square miles is industrial, which assumes that no one would live there but that work might be done there during the day. The inner area is planned to be used long term for waste management.
It includes Hanford’s lined landfill for low-level radioactive waste. It also could include the shells of the site’s 177 underground waste tanks, with residual waste left after they are emptied, if the decision is made to bury them in place.
Cleanup decisions have not been made for most of Hanford’s large chemical processing plants in central Hanford. But cleanup could follow the plan for the first one to be tackled, the 810-foot-long U Plant. The U Plant plan calls for placing equipment in the plant’s below-deck cells, then partially collapsing and covering its walls.
The advisory board wants DOE and its regulators, collectively called the Tri-Party Agencies, to evaluate future risk there based on a broader scenario than industrial use as it sets environmental cleanup standards.
The region’s Native American tribes and DOE disagree on whether treaty rights for activities such as gathering food extend to all of Hanford, including central Hanford, where land will continue to be used for waste management. Until the issue is settled by the courts or Congress, DOE should consider assessing risk based on tribal activities, according to notes summarizing early advisory board discussions.
DOE has floated the idea of studying the cleanup of contaminants down to 10 feet below the ground surface in addition to studying cleanup down to 15 feet deep.
There are pipelines used to move waste deeper than 10 feet underground, Cimon said. There also are junction boxes where leaks occurred. They were covered with asphalt to protect workers so plutonium production could continue with little interruption, she said.
Setting a depth for cleanup is not reasonable without a better understanding of the type and quantities of waste and an understanding of contamination in the soil and in the groundwater in central Hanford, the board said in its letter. The board also is concerned that studies have shown native plants, such as old growth sage, may have roots that reach more than 10 to 15 feet underground, Cimon said.
The board recommends that the same observational approach used on contaminant cleanup closer to the Columbia River be used. Near the river digging continued until cleanup requirements were met or there was no technology left that made further cleanup possible, Cimon said.
The board said it was concerned about the lack of focus on contaminants in soil from near the surface down to groundwater.
In time some areas of undisturbed sagebrush might be excluded from the proposed 10-square-mile footprint of the inner area, requiring less acreage to be monitored and maintained as an industrial area, the board said.