While not flat-out opposed to future use of grout for radioactive tank waste at the Department of Energy’s Hanford Site, state officials in Washington and Oregon said Thursday feds for now should not become distracted from the more immediate task of converting low-activity waste into a stabler glass form.
Direct-feed low-activity waste (DFLAW) treatment at the Hanford Site Waste Treatment Plant “is almost ready to run,” Suzanne Dahl, tank waste section manager for the Washington Department of Ecology, told a National Academies of Science panel studying options for supplemental low-activity waste treatments.
“You want to be able to support things like this, but not at the expense of the core mission,” Dahl told a panel of the NAS Nuclear and Radiation Studies Board. The vitrification plant is expected to start converting low-activity waste into a glass form using DFLAW by the end of 2023.
By contrast, the need for supplemental low-activity waste facilities to handle low-activity waste that cannot run through the Waste Treatment Plant, might not be needed for “decades,” Dahl said.
The Waste Treatment Plant might have only enough capacity for half of the low activity waste in Hanford’s tanks. In addition, vitrifying high-level waste will create more low-level waste, speakers told the panel during the two-day virtual meeting that started Wednesday.
Startup of the DFLAW, eventual operation of high-level waste vitrification facilities and the Pretreatment Facility, on hold since 2012 due to unresolved technical problems, all take priority over options for supplemental waste, Dahl said.
The Washington Ecology official also hinted that Pretreatment Facility options will be affected by the ongoing “holistic” negotiations between her agency, DOE and the U.S. Environmental Protection Agency (EPA). Dahl told the panel she was limited in what she could say, given the confidential nature of the talks.
The NAS panel’s work, expected to yield a draft report in April 2022 followed by a final one in November 2022, is happening at an awkward time, said Jeff Burright, a radioactive waste remediation specialist at the Oregon Department of Energy.
On one hand, “we have this Congressionally-mandated study” by the National Academies while major federal-state negotiations on future plans affecting Hanford cleanup are taking place behind closed doors,” Burright said.
“Grout is coming to Hanford in one way or another,” at some point, Burright said. But the federal government appears to be a long way from a “decision ready” analysis on the comparative risks and benefits of using grout for supplemental low-activity waste that cannot be accommodated at the Waste Treatment Plant, he said.
Washington state’s preference for technology “as good as glass” when it comes to treating Hanford waste was not drawn up in isolation, but in consultation with EPA and DOE, Dahl said. Washington continues to prefer vitrifying all of Hanford’s high-level waste and almost all of the low-activity waste, save for its “incremental” embrace of the so-called “test-bed initiative,” she added.
Perma-Fix Environmental Services did a pilot in which it grouted 3 gallons of Hanford LAW and shipped it to Waste Control Specialists in Texas and DOE is studying plans for a larger, 2,000-gallon demonstration.
As directed by the 2021 National Defense Authorization Act, the 15-member Nuclear and Radiation Studies Board of the National Academies of Science is doing its second major review into potential alternative ways to treat supplement low-activity waste at Hanford. The group, chaired by John Applegate, interim provost and executive vice president of Indiana University, will ultimately make only a recommendation about supplemental low-activity waste.
Prior research by the National Academies panel and the Savannah River National Laboratory found grouting is the cheapest option while vitrification is the most expensive, albeit the most thorough for lowering radioactive risk.
Another choice is steam reforming, the technology to be utilized to immobilize sodium-bearing waste in the Idaho National Laboratory’s (INL) Integrated Waste Treatment Unit, which is taking much longer to get up and running than DOE anticipated.
There is roughly 56 million gallons of radioactive and chemical tank waste remaining from Hanford’s days as a plutonium producer for the military and about 90% is low-activity waste.
