Liquid waste processing at the Savannah River Site almost restarted last month after a 15-month outage, but is instead slated to begin next week after workers fix a seal at the site’s major waste processing facility that allows treated waste to properly pour into the storage canister.
Chemical operations at the 310-square-muile site near Aiken, S.C., including pretreatment of liquid waste sludge, resumed on May 8, an Energy Department spokesperson said by email.
On May 31, liquid waste contractor Savannah River Remediation (SRR) attempted to resume waste pouring at the site’s Defense Waste Processing Facility (DWPF), which converts radioactive liquid sludge into a glassy, less harmful material suitable for interim storage at SRS.
The spokesperson said the DWPF melter – which mixes the waste as part of the vitrification process – began pouring the waste into a stainless steel storage canister. At that point, workers realized the seal between the canister and the melter were not properly aligned. That could potentially cause a waste leak, though that did not occur, according to the spokesperson.
“Glass pouring was suspended to investigate and resolve the issue,” the DOE official wrote. “There was no impact to staff or the environment. Glass pouring is expected to resume within a week.”
At that point, liquid waste operations should be back up and running like they were prior to February 2017, when the outage began. The halt began to replace the DWPF’s Melter 2: the 65-ton refractory-lined melting vessel that receives high-level waste, mixes it to form the molten glass, and pours into the canisters for storage. The melter malfunctioned after 14 years of service.
The Energy Department and Savannah River Remediation (SRR) spent much of last year on the $3 million installation of the replacement Melter 3. Once it arrived at DWPF in August, the melter had to be connected to the liquid waste system and tested to ensure it was ready for operations. In December, Melter 3 began pouring waste that was treated before the outage.
All told, SRS houses more than 30 million gallons of liquid waste in 43 underground storage tanks. About 10 percent of that material is sludge and goes to DWPF for processing. The rest is salt waste and is treated under a different process.
The outage has not impacted the long-term schedule because the SRS Liquid Waste System Plan is padded to account for such events. The SRS liquid waste mission is expected to last until 2039 and carries a life-cycle cost of $33 billion to $57 billion
