The Department of Energy should not delay work to clean up the highly radioactive spill from a hot cell in a Hanford building just north of Richland, the Hanford Advisory Board said Friday.
DOE and its regulators, the Washington State Department of Ecology and the Environmental Protection Agency, have proposed revised deadlines to the legally binding Tri-Party Agreement.
They include extending the deadline for tearing down the 324 Building, where concentrated cesium and strontium spilled into the soil beneath it, for three years past the current deadline of September 2015.
The deadline had been set before workers discovered the highly contaminated soil in 2010. The lining of a sump at the bottom of a hot cell in the building had cracked, allowing radioactive material to leak into the soil, possibly when a large spill of cesium and strontium happened in the hot cell in 1986.
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Radioactivity has been measured at 8,900 rad per hour, which would be about 10 times the lethal dose on contact, according to Hanford officials.
"This is extremely high radiation. Nothing else compares in the river corridor," said Mark French, DOE project director for environmental cleanup in the river corridor, when the spill was discovered. The river corridor encompasses 75 square miles of the nuclear reservation along the Columbia River.
Now radiation from the spill is shielded by the building above it and there is no evidence the spill has reached the groundwater, which is about 42 feet below the bottom of the hot cell. The worst of the contaminated soil is believed to be 5 to 6 feet beneath the hot cell.
However, there is a concern that two water lines have broken near the contaminated soil, said Pam Larsen, who represents the city of Richland on the board.
Although the water is not believed to have hit the spill, if it did it could have spread the cesium and strontium toward the groundwater. The 324 Building is 1,000 feet from the Columbia River.
"There is a risk. It is very near town," Larsen said.
The board also is concerned that leaving the 324 Building standing with the leak beneath it will further delay completion of the cleanup and closure of the Hanford 300 Area just north of Richland, which had been planned to be finished in 2015.
"Having a building there puts a screeching halt to cleanup of the 300 Area," said Dick Smith, who represents the city of Kennewick on the board.
Given the already tight Hanford budget, the board said DOE should seek additional money to clean up the contaminated soil.
Chances of getting the money are slim, but the board still should be on record as requesting it, Smith said.
Other changes to Tri-Party Agreement deadlines also have been proposed because of other newly discovered contamination, such as extensive chromium contamination down to groundwater near the river, and to build experience before tackling some challenging central Hanford work.
The board did not object to the other proposed deadline changes.
"Although the board does have some concerns about an established pattern of delaying cleanup activities through changes to the Tri-Party Agreement, we recognize that the modifications contained within this proposed change package represent the reality of where we are today," the board said in a document to be sent to DOE and its regulators.
"While milestones are the very backbone that supports strategically planned cleanup work and tracks progress as the cleanup activities continue to completion, the ultimate goal is safe and effective Hanford cleanup," it said.