A key piece of equipment needed for liquid waste disposal at the Savannah River Site (SRS) in South Carolina has successfully been replaced, but the yearlong outage of liquid waste processing remains in effect, the Department of Energy said Tuesday.
Melter 3 is in place and operational as of Dec. 29, when it began pouring treated waste into a storage canister, SRS said. The waste was treated last year by the melter, but had not yet been poured.
The Energy Department reported in February 2017 that it had to replace Savannah River’s Defense Waste Processing Facility’s Melter 2: a 65-ton refractory-lined melting vessel that receives high-level waste, then combines it with a mixture known as borosilicate frit to remove contamination. When heated in the melter, these elements form a molten glass, which is then poured into stainless-steel canisters for safe storage. The waste is temporarily stored at SRS, but will eventually be shipped away once the DOE identifies a permanent disposal facility.
The removal of Melter 2 and installation of Melter 3 required SRS to implement a site-wide liquid waste processing outage for nearly the entire calendar year.
The Defense Waste Processing Facility is designed to process over 30 million gallons of radioactive sludge and salt waste stored in more than 40 waste storage tanks, a byproduct of Cold War nuclear weapons operations at SRS.
On Tuesday, SRS announced Melter 3 on Dec. 29 poured its first canisters of waste. Specifically, the melter completed filling a canister that Melter 2 had been filling when it malfunctioned, and then poured a full canister on Jan. 1. As of Tuesday, the new melter has filled six more canisters.
“Stabilizing and safely storing highly radioactive waste is an important part of the Department of Energy’s mission to remediate the Cold War-era liquid waste at SRS,” site manager Jack Craig said in the Tuesday press release. “The new melter allows us to continue this important mission.”
The swap was a $3 million project that took most of 2017. As the name indicates, Melter 2 was the second melter used at the DWPF. It functioned for close to 14 years and poured 2,819 canisters. Prior to that, Melter 1 lasted six years and produced 1,339 canisters, totaling 4,158 storage containers between the two melters. The site predicts that DWPF will pour 8,170 total canisters.
All told, liquid waste cleanup at SRS is projected to take until 2065, with a life-cycle cost of up to $109 billion, according to the Energy Department. That timeline extends well beyond the projected use of DWPF, which is expected to run until 2038.
Despite the melter replacement, the liquid outage will continue, SRS reported. Pouring of treated waste from the melter is not considered part of the outage.
The Energy Department did not offer a timeline for the conclusion of the freeze, but noted that several other activities have to be completed before DWPF can resume treating waste. These include maintenance on electrical and steam systems, and on the chemical processing cells at DWPF.
The site said there are no long-term impacts to the waste processing schedule because melter replacements are part of the SRS Liquid Waste System Plan. The plan pads the schedule for liquid waste completion by assuming outages for infrastructure repairs and replacements.
