2023 priority: Under an agreement with Washington’s Department of Ecology, the DOE was to begin treating Hanford’s low-activity tank waste, immobilizing it in glass by vitrification, through the DFLAW program by the end of 2023.
While the DOE was allowed last year to push that deadline to August 2025 due to pandemic-related delays, the department had hoped to stay close to its original schedule, listing as one of its 2022 priorities the completion of cold commissioning of the first of Hanford’s two 300-ton vitrification melters.
Heating of the first melter and initiating heat-up of the second melter are listed as one of the DOE’s top priorities for 2023.
Melter delays: The DOE was on its way to meeting that goal when it began heating up the first melter in October 2022. Located in the Low-Activity Waste Facility, part of Hanford’s Waste Treatment and Immobilization Plant (WTP), the melters are designed to operate continuously at 2,100°F.
Soon after the process started, however, heat-up of the first melter was paused when crews encountered an abnormal condition in the power supply to the melter’s 18 temporary start-up heaters. At the time, the DOE did not indicate when heat-up would resume.
Vulnerabilities: Also speaking at the Waste Management Symposia was Tom Fletcher, assistant manager for the WTP, who explained that during the heat-up process the melter experienced a “component failure” related to its start-up heaters, which initiate the melting of the glass frit and waste mix. While that issue has since been resolved, Fletcher said that a “vulnerability” was found in the melter’s Joule heating system, which maintains inductive heat in the melter after the temporary heaters are removed.
“We are currently solving that as we speak,” Fletcher said of the vulnerability. “And we are going to go through a very methodical testing and we will come out the other side here in the coming weeks to months with a system that we are able to operate and get back up and running.”
Vance concurred, saying that it will take a few weeks to up to two months to resume heat-up of the melters, after which nonradioactive waste simulants will be added to test and verify processes before the vitrification of low-level radioactive waste can begin.
“I think the team is on a good trajectory to deliver in 2024, and I would say December 31, 2024, is a very good bet,” Vance said of beginning DFLAW operations at WTP.
