Workers at the Hanford Site in Washington state successfully transferred the first batch of highly radioactive sludge out of underwater storage in the K West Reactor Basin late Tuesday afternoon. The Department of Energy had a Tri-Party Agreement deadline, reset most recently in 2015, to start removing sludge from the basin by the end of this fiscal year.
Workers have been preparing for the transfer since 2009, following the consolidation of the sludge from underwater containers in the K East Reactor Basin into the K West Reactor Basin. The sludge was the result of irradiated fuel that was stored in the K Reactor basins at the end of the Cold War rather than being processed to remove plutonium. Before the fuel was removed from the basins in 2004, it degraded and mixed with dirt in the pools to form 35 cubic yards of sludge. The sludge contains fuel corrosion particles, bits of metal, and dirt.
“The sludge is some of the most hazardous material at Hanford, so moving it away from the river to safe storage in a robust engineered facility in the center of the site significantly reduces risk,” Doug Shoop, manager of the DOE Richland Operations Office at Hanford, said in a statement Wednesday.
Space in the large Maintenance and Storage Facility at the nuclear cleanup site was used to create a mock-up of the K West Basin and the sludge transfer annex. Equipment designed and fabricated for the transfer was tested there; workers practiced on the equipment, providing feedback for improvements.
“I’m pleased with the amount of planning, training and engineering that has gone into this sludge transfer,” said Rod Lobos, an environmental engineer with the Environmental Protection Agency, a Hanford regulator. “So far, so good. I hope this continues.”
The 13-minute initial transfer Tuesday went better than expected, said Ray Geimer, vice president of K Basin operations for cleanup contractor CH2M Hill Plateau Remediation Co. CH2M had anticipated moving 200 to 300 pounds of sludge in a slurry that was 95 percent water in the first transfer. But workers were able to move a mixture of up to 14.5 percent solids through shielded transfer lines from the basin to the annex to get 650 pounds of solids moved in the initial transfer. “It went flawlessly,” said Mark French, DOE project director.
Plans call for allowing solids to settle in a transport and storage container inside the annex after each transfer. Some excess water can then be removed and more sludge added to the container. Several feet of water will be left at the top of the container to provide shielding for workers as they disconnect transfer hoses from the containers.
The first container, which is inside a shielded cask, is expected to be ready to be trucked the 12 miles to T Plant in central Hanford during the last week of June. About 18 to 24 containers, each 10 feet tall, are due to be filled and transported to T Plant, which was once used to chemically process irradiated fuel to remove plutonium. They will be delivered through a tunnel to the plant’s below-ground cells for storage. Safety features include secondary containment basins and leak detectors.
The Energy Department is required by the Tri-Party Agreement to transfer all the sludge to T Plant by the end of 2019. Treatment technology to prepare the waste for disposal must be selected by 2022, and the basin demolished by September 2023. Both the K West and K East reactors are required to be cocooned, or placed in interim storage, by 2024.
