After an alarm on a control panel, the Department of Energy has temporarily stopped heating up the first melter for the Waste Treatment and Immobilization Plant at the Hanford Site in Washington state, an advisory panel was told Thursday.
The news was shared with a virtual meeting of the Hanford Advisory Board by Mat Irwin, DOE’s deputy Direct-Feed Low-Activity Waste program manager, and Chris Musick, Bechtel’s deputy director for the vitrification plant.
Specifically, an electrical control panel that controls six of the melter’s 18 startup heaters “got a high-temperature alarm … and the temperature continued to rise,” Musick said during a presentation to the Hanford Advisory Board.
The alarm originated from a switch on the control panel that might be described as somewhat akin to a breaker, a DOE spokesperson said by phone Friday.
The federal agency stopped the warmup around midnight Oct. 10, a couple of days after the melter started to warm up. The pause occurred just before reaching the first 48-hour holding point at 300 degrees Fahrenheit, Irwin said.
Operators had planned to gradually heat up the melter to 2,100 degrees Fahrenheit, Irwin said. The melter is designed to super-heat the radioactive tank waste that will ultimately be blended with small beads or frit and more than a dozen chemicals to solidify waste into a glass-like form.
“The decision to systematically cool down occurred at 11:30 (p.m.),” Irwin told the advisory board. The temperature of the melter unit is currently back at ambient levels until technical crews figure out the problem, Irwin said.
A technical team, which includes international experts is “swarming” around the power supply cabinet where the alarm originated, Irwin said. The DOE official said there is no danger of any damage to the melter.
Irwin said the temporary shutdown is not an emergency situation but just one of the hiccups expected in starting up a multi-billion-dollar capital infrastructure project.
“Heating up the melter is a complex process that consists of a series of activities over at least several weeks to prepare for and establish a molten pool of glass that will eventually be used to vitrify low level tank waste,” a DOE spokesperson said in an email statement. “The detailed and methodical process for melter heat up has been planned in a way that allows for issues identified during the complex startup to be effectively and safely addressed.”
Turning radioactive waste into glass is a technology that has been proven before at both the Savannah River Site in South Carolina as well as the Sellafield nuclear site in the United Kingdom, Irwin said.
Since December 2000 Bechtel has held the contract to build the glass making plant at Hanford, a business currently valued at $15 billion. The DOE and Bechtel are currently shooting for hot commissioning and startup of low-level waste vitrification by December 2023, although it has permission from a federal court to extend the work into 2024 if necessary.