Work crews have finished shoring up three old liquid waste disposal structures in danger of collapse at the Hanford Site in Washington state, the Department of Energy and contractor Central Plateau Cleanup Co. said Thursday.
“With this work completed, Hanford has ensured the stability of these structures and reduced risks to workers and the environment,” a DOE spokesman at Hanford said in an emailed statement. The structures are located near the former Plutonium Finishing Plant.
“The Z-9 crib and the Z-361 holding tank have been stabilized with engineered grout,” the spokesman said. “Additional assessments on the Z-2 crib demonstrate that the existing soil provides proper protection.”
A memo to employees from the president of Central Plateau Cleanup Co., Scott Sax, went into a bit more detail on the Z-2 crib. “When this additional soil was considered in the revised risk analysis, it was determined that this thicker layer of soil provides proper protection in the event of a crib collapse,” Sax said.
“We will continue to monitor all three structures to ensure they remain stable,” until a longer-term solution is implemented.
In early 2020, DOE told the Environmental Protection Agency it wanted to move quickly on the stabilization project. The newest of the three structures stopped taking waste in the 1970s, and all are contaminated with plutonium and are in danger of failure, DOE said at the time. DOE said it wanted to prevent another accident similar to the May 2017 partial collapse of Tunnel 1 at Hanford’s Plutonium Uranium Extraction (PUREX) Plant.
The DOE has said shoring up the three underground vaults or cribs, while not an emergency, was time sensitive. The prior cleanup prime, CH2M Hill Plateau Remediation, issued a $3.9 million subcontract to White Shield, of Pasco, Wash., in April 2020 to design and install the engineered grout at the three sites.
In its final scorecard, CH2M Hill Plateau Remediation earned 78% of the fee available to it for about four months of work at the Department of Energy’s Hanford Site in Washington state.
Altogether, the Jacobs subsidiary pocketed $6.36 million out of an available $8.16 million for the period from Oct. 1, 2020 through Jan. 24, 2021. On the subjective performance, it earned $2.8 million out of $4.08 million and on the objective grading it took home $3.55 million out of $4.08 million.
The bottom line is not dramatically different from CH2M’s recent performance reviews. It earned about 83% of its overall fee in its scorecard for fiscal 2020. Before that it took home 79% of its fee for fiscal 2019.
Central Plateau Cleanup Co., made up of Amentum, Fluor, and Atkins, took over as Hanford’s main solid waste contractor in January. The team won the potentially 10-year, $10 billion contract for remediation at Hanford’s Central Plateau in December 2019, but bid protests and a delayed transition due to the COVID-19 pandemic held up the switch from CH2M Hill.
CH2M Hill Plateau Remediation Co., had been on the job since October 2008 under a $6.4 billion contract.
In its final months on the job, CH2M “met or exceeded the majority of performance goals and objectives for the performance period,” according to the assessment from the DOE Office of Environmental Management.
The DOE credited CH2M with ensuring a smooth transition to the new contractor, an effective COVID-19 response and construction startup on the Waste Encapsulation Storage Facility Modification Project that is designed to support transfer of cesium and strontium capsules from wet to dry storage.
The “areas for improvement” include the quality and timeliness of nuclear safety documentation, performing required subcontractor audits and management of aging structures, according to the DOE document. The latter has been the subject of increased DOE emphasis at Hanford since May 2017 when a segment of Tunnel 1 at the Plutonium Uranium Extraction (PUREX) Plant was found partly collapsed. The agency started taking a look at other Hanford structures in danger of falling in, such as three old underground waste structures at the Plutonium Finishing Plant.
