Congress should consider passing a law authorizing the Department of Energy to use grout to stabilize some of Hanford’s radioactive tank waste, rather than turning it into a glass form, according to a Government Accountability Office report released Wednesday.
The report argues that grouting is less expensive than vitrification, which turns the waste into glass, and might allow the waste to be treated sooner.
However, the state of Washington has long insisted that any waste disposed of at Hanford be incorporated in glass to best protect the environment.
“We’re still evaluating the GAO report, but we remain firm in our conviction that vitrification, or glass, is the superior process,” said Alex Smith, manager for the state Department of Ecology’s Nuclear Waste Program, on Wednesday.
DOE would need the state to approve a hazardous waste permit before it could dispose of the treated waste at Hanford, as is planned now for much of the waste.
The Hanford nuclear reservation has 56 million gallons of a mixture of radioactive and hazardous chemical waste stored in underground tanks until it can be treated for disposal.
Ground was broken in 2002 for a vitrification plant — with a price tag now expected to top $17 billion — to treat much of the waste by separating it into high-level radioactive and low-activity radioactive waste streams.
Our recommendations are to help ensure that DOE treats the remaining waste based on the risk it poses, while also considering costs.
The high-activity waste would be immobilized in glass logs and shipped to a national repository, initially expected to be at Yucca Mountain, Nev.
But most of the waste — about 90 percent — is expected to be low-activity waste. It is primarily the liquid portion of the tank waste that remains after as much radioactive material as technically and economically practical has been removed.
The treated low-activity waste is planned to be buried at Hanford. A lined landfill already has been finished in central Hanford to hold the low-activity glass logs produced at the vitrification plant.
DOE expects the vitrification plant to start producing low-activity radioactive waste glass as soon as 2022, which would beat a legal requirement by a year.
But a decision has not been made on whether all the low-activity tank waste will be treated at the plant. It was not designed to treat all the low-activity waste in a reasonable time.
The GAO report proposes looking at grouting as a way to treat the remaining Hanford low-activity waste — possibly a third to a half of the low-activity waste.
“Our recommendations are to help ensure that DOE treats the remaining waste based on the risk it poses, while also considering costs,” the GAO said in a fact sheet.
The National Academies of Sciences, Engineering and Medicine convened a meeting for GAO with 21 experts to consider the merits of vitrifying versus grouting waste, the report said.
Given the history of delays in treating tank waste, we would hate to see this report divert attention and, more importantly, redirect critical funding away from the ongoing work to get treatment processes up and running by 2023.
Alex Smith, manager for the state Department of Ecology’s Nuclear Waste Program
The experts agreed that both vitrification and grout could effectively treat Hanford’s low-activity radioactive tank waste, the report said.
Some experts also thought that grouting waste could be done more quickly than vitrification, benefiting the environment at Hanford.
Much of the waste waiting for vitrification is stored in underground single-shell tanks that are prone to leaking, after being used decades longer than planned when they were built.
When the decision was made more than 20 years ago to vitrify Hanford tank waste, DOE determined that vitrification was better than other methods for encapsulating the complex mixture of radioactive and hazardous chemicals that make up Hanford waste.
But since then, grout and vitrification technologies have matured and new scientific information has been developed, the GAO report said.
Earlier assumptions about grout no longer appear to be accurate, particularly considering the dry climate of Hanford and that the disposal site for the waste at Hanford would be engineered to keep precipitation from infiltrating and leaching any waste from the disposal site, the GAO report said.
One expert said that if waste did leach from the landfill, it would take 2,000 years for it to enter the groundwater and then it would be highly diluted, the GAO report said.
$19 billion spent by DOE on different tank waste treatment strategies
0 gallons of Hanford tank waste treated for disposal
However, the state maintains glass would be superior.
“A succession of studies have verified that conclusion, based both on long-term protection of the environment and cost-effectiveness, which is why glass became the chosen technology to treat Hanford’s tank waste,” Smith said.
“Given the history of delays in treating tank waste, we would hate to see this report divert attention and, more importantly, redirect critical funding away from the ongoing work to get treatment processes up and running by 2023,” she said.
The GAO report recommends that DOE develop updated information on alternate methods or alternate disposal sites for some of Hanford’s tank waste. It also recommends a study looking at the total costs of different treatment and disposal scenarios.
Congress in 2004 passed legislation that made clear that low-activity radioactive waste at DOE’s Savannah River, S.C., site could be managed in certain ways. The legislation did not cover Hanford, which the GAO report suggests Congress reconsider now.
In 2004, DOE estimated that grouting the low-activity portion of the waste at Savannah River, rather than vitrifying it, would save $55 billion.
Unlike Washington state, South Carolina allowed grouting, and since then 4 million gallons of Savannah River waste have been grouted.
The GAO report pointed out that no tank waste has been treated at Hanford, despite DOE spending more than $19 billion on several different tank waste treatment strategies.
We can’t afford to get distracted from the job at hand.
Sen. Maria Cantwell, D-Wash
The report acknowledges that because of the many processes used over decades at Hanford to to produce plutonium, its tank waste is a more complex mixture of radioactive and hazardous chemical components than the Savannah River tank waste.
DOE agreed with the recommendations in the report for more study, saying it has been looking for ways to reduce costs and speed Hanford cleanup since 2013.
It already has commissioned a review of treatment options to be independently reviewed by the National Academy of Sciences, it said in a letter to the GAO. The report will include a cost benefit analysis for treatment and disposal options.
DOE also is looking at ways to incorporate significantly more low-activity waste into each container of glass produced at the vitrification plant, which could allow the vit plant to treat more low-activity radioactive waste in a reasonable time than the half to two-thirds of it earlier estimated.
Congress may be a tougher sell on the recommendation that it pass legislation to help clear the way toward grouting Hanford waste.
“We can’t afford to get distracted from the job at hand,” Sen. Maria Cantwell, D-Wash., said Wednesday.
Cleanup decisions must be guided by the best science, she said.