After a nine-month pause, testing is scheduled to start again next week at the Integrated Waste Treatment Unit, contractor officials said.
The first 10-day test run will examine the effectiveness of a modified auger grinder — a piece of machinery designed to chew up the solid radioactive waste that comes out of the treatment process. The component clogged and seized up during previous tests.
Twenty-day and 50-day test runs will follow to study other recent improvements made at the 53,000-square-foot facility, but officials aren’t yet sure when those tests will begin. DOE and contractor officials have stopped offering a timeline when the facility will be operational.
“The schedule is built on success,” Fluor Idaho President Fred Hughes said in a recent interview.
Officials remain hopeful that Fluor, which took over in June, can make headway on the problem-plagued facility where previous contractor CH2M-WG Idaho failed. Under the terms of its contract, Fluor was allowed to take a more methodical approach on starting up the plant, conducting off-site testing in Colorado and bringing in experts from around the country to help.
The facility was built to treat 900,000 gallons of radioactive sodium-bearing waste by 2012, but has been unable to get past the testing phase. It is more than $200 million over budget, and DOE continues to be fined $3,600 daily by the Idaho Department of Environmental Quality after missing an October deadline. About $500,000 has accrued so far. The fines will continue until the facility is treating waste, or the state and DOE agree on a new schedule.
Problems at the facility center around the Denitration Mineralization Reformer, or DMR — a 20-foot-tall metal processing vessel where the waste is treated.
Liquid radioactive waste — or for now a “simulant” material — is injected into the vessel, which is superheated to about 1,200 degrees. Gases and sand-like particles also shoot into the vessel. The liquid waste clings to the particles and solidifies, creating a more manageable waste form.
From the DMR, the hardened waste product drops down into the auger grinder for further processing, before being cooled and packaged for storage.
During the last simulant run in May, officials say they finally created the granular waste product they’ve been hoping for. But many issues with the treatment process still needed fixing.
For one, the previous auger grinder design wasn’t effective.
“What we were finding was, with the environmental conditions that were down in that auger grinder, it was turning the material into a cement, and seizing up,” Hughes said.
If such a problem occurred during treatment of real radioactive waste, it would be next to impossible to safely repair. So Fluor officials worked with Idaho Falls company Diversified Metal Products to redesign the component.
Fluor will test the new stainless steel version this month. If it works, Diversified will manufacture a permanent replacement using a rare and expensive alloy called Haynes 556 — a material some Fluor employees have nicknamed “unobtainium.” The special material can handle the plant’s hot, highly corrosive environment, officials said.
Meanwhile, tests on a small-scale mockup version of the DMR are underway at Hazen Research, outside Denver. Officials want to ensure they can control particle size. One ongoing problem is particles that clump together and cause a bark-like material. They also are studying temperatures, as the process might work better with more heat.
Officials also plan to replace the “ring header,” a component inside the DMR which sprays gases. But the DMR is sealed off from the outside, so Fluor employees plan to cut a small hole in the side to allow a worker to squeeze through and install the new piece of equipment.
After the three upcoming test runs are complete, one final 90-day simulant run is planned, followed by a 30-day outage to inspect the facility for any lingering problems.
That will be followed by treatment of the actual radioactive waste, a process expected to last 18 months to two years. The solidified waste will fill about 700 metal canisters that will be placed inside about 40 concrete vaults stored at the facility.
Craig Olson, the facility project manager, said for the last four years, employees have fixed numerous issues elsewhere around the plant. Now, he said, it’s all down to the DMR.
“We’ve pulled in the experts,” he said. “It’s a very solid approach.”
Considering the facility is the first of its kind, expectations to have it operational within only a few years were never realistic, said Jimmy Spells, a manager at the plant. But both Spells and Olson said they believe the treatment process will work eventually.
“We’re learning the lessons as we go through,” Spells said.
Luke Ramseth can be reached at 542-6763. Twitter: @lramseth