Repairs of a key waste processing facility at the Department of Energy’s Savannah River Site remain on schedule for completion in 2017, but the work is taking a toll on short-term efforts to rid the facility of radioactive waste, officials reaffirmed Monday.
In the interim, there is no liquid waste processing going on at SRS right now, due to the failure of Melter 2, a 65-ton, refractory-lined melting vessel that functions as part of the Defense Waste Processing Facility (DWPF). The facility converts radioactive sludge waste at SRS into a solid glass form for permanent storage. The site reported last month that liquid waste contractor Savannah River Remediation (SRR) is preparing to replace the melter, which heats the sludge waste and mixes it with a material known as borosilicate frit to remove contamination. The mixture forms a molten, glassy product that is poured into stainless steel canisters.
The site produced 52 canisters this fiscal year. DWPF is not projected to pour any more canisters before the next budget year begins on Oct. 1, meaning it will fall short of the original goal of 100 canisters. By comparison, the site filled 136 canisters last year, falling slightly short of the 150-canister goal.
All told, roughly 35 million gallons of highly radioactive waste is stored in more than 40 SRS tanks. The waste is a byproduct of nuclear weapons production during the Cold War.
The Savannah River Site reported on Feb. 3 that it had begun work to replace the melter, which had handled 10 million pounds of material – enough to fill 2,819 canisters. During an SRS Citizens Advisory Board (CAB) meeting on Monday, Savannah River Remediation Waste Treatment Outage Manager Wesley Bryan explained that Melter 2 outlived its projected lifetime by lasting for nearly 14 years. Bryan said the melter was designed to last just two years, but that high performance and routine monitoring kept it running.
“We eliminated risks to personnel by not having to do outages every two years or so,” he said. “There’s a significant amount of savings that goes along with that.”
Because the waste processing facilities are integrated and depend on each other for operation, the melter failure has resulted in a site-wide liquid waste waste processing outage. It will take most of the rest of the year to bring Melter 3 online and tie it in to DWPF and the Modular Caustic Solvent Extraction Unit (MCU), which processes the salt waste stored in the SRS tanks.
Salt waste accounts for roughly 90 percent of the tank waste volume at SRS. In late 2018, the site is expected to start up the larger Salt Waste Processing Facility, which will boost waste processing from 1.5 million gallons a year to 6 million.
Melter 3 has been in storage for a number of years. Once Melter 2 is fully disassembled and removed from DWPF, Melter 3 will be taken from storage and undergo multiple levels of testing and evaluation before it is transported to the facility. The melter is expected to be installed by the fall – including tie-ins to DWPF and MCU – and operating by the end of the year. The entire project is expected to cost $40 million to $50 million, said DOE spokesman Jim Folk.
Folk added that the almost-yearlong pause at DWPF will result in a significant, short-term impact in SRS waste processing. “When the melter is down, the entire system is down, including all salt processing and everything else,” he said. “So it is a significant impact to the program.”
Long term, the impacts of the outage are minimal, a site spokesperson said last month. “In terms of the lifecycle of liquid waste work, this outage will have little, if any, impact,” the spokesperson wrote in an email. “These outages are factored into the Liquid Waste System Plan.”
According to DOE estimates, liquid waste cleanup at SRS is projected to take until 2065, with a life-cycle cost of up to $109 billion.
