The Department of Energy’s solid-waste cleanup contractor at the Hanford Site in Washington state now recommends tearing down the above-ground portion of the decaying 324 Building before digging up radioactively-contaminated soil under the structure’s B cell.
In an Aug. 23 presentation to the Hanford Advisory Board, Central Plateau Cleanup Co. President John Eschenberg said he now favors deactivation of the 324 Building, demolishing the structure down to slab, followed by construction of a new “containment superstructure” and lastly remediation of the contaminated soil located less than 1,000 feet from the Columbia River.
The proposed change could delay final cleanup of the building and its immediate environs by three years or more, Hanford Advisory Board members said during last week’s meeting. The changes also need the blessing of Hanford’s state and federal regulators, who said during the meeting they need to hear more details.
Under the Tri-Party agreement that governs cleanup at Hanford, DOE is supposed to remove the contaminated soil by 2025 and take down the 324 building by 2030, a U.S. Environmental Protection Agency (EPA) spokesperson told Exchange Monitor in July. The agency, along with DOE and Washington state, are the three parties to the agreement.
Eschenberg said the change is necessary for multiple reasons: recent discovery that soil contamination is much worse than earlier thought; troubles encountered in drilling under the building and the radiological risk and safety hazards posed by the deteriorating structure that is more than a half-century old.
Since at least 2018, DOE has planned to cut below the B cell floor and remove highly-contaminated soil using equipment with remotely-controlled arms.
But “the size of the waste site is much larger” than what was modeled more than a decade ago, Eschenberg said. “The remote excavator arms are no longer a viable approach to removing all of the radioactive soil beneath the B cell” because the remote arms can only reach about 25% of the contamination, Eschenberg said.
“The proposed four-phase approach is safer for workers, protective of the Columbia River, and effective in demolishing the 324 Building and remediating the soil beneath,” Eschenberg said.
“We are working with DOE and EPA to assess the next steps within the CERCLA [Comprehensive Environmental Response, Compensation, and Liability Act] process,” a contractor spokesperson said by email Sunday.
The 324 Building was used for research on highly radioactive materials between 1966 and 1996 and for part of its last years was not particularly well-maintained, Eschenberg told the board. Some cranes relied upon at the building have experienced operational issues, he added.
Sen. Patty Murray (D-Wash.) has said 324 cleanup should be a priority.
