The manager in charge of the effort to fix a Savannah River Site evaporator pot that unexpectedly sprung a leak halfway through its 30-year design life is 95-percent sure the vessel will be up and running again by Dec. 31.
The 3H Evaporator Pot, which last year leaked some 3,000 gallons of highly radioactive liquid waste, is an essential part of the chemical separations process at the South Carolina site’s H Canyon: a Cold War-era plant now used by the Department of Energy to dilute highly enriched uranium but once employed to isolate fissile materials for nuclear weapons.
Chemical separation creates liquid waste that is piped into SRS’ underground tank farms. The amount of waste in the tanks can be reduced by boiling the water out using the 30-foot-high 3H Evaporator Pot. That creates more space in the tank farms, which in turn allows chemical separation to continue. Without the 3H Evaporator Pot, the tank farms would fill up around 2019, grinding chemical separation — an essential part of the U.S. nuclear nonproliferation program — to a halt.
In a webcast meeting this week with the local Savannah River Site Citizens Advisory Board in Augusta, Ga., an executive with site liquid waste management contractor Savannah River Remediation (SRR) said the 3H pot, which was made by Joseph Oat Corp. of Camden, N.J., can be patched for about $2 million: some $10 million less than it would cost to fix the massive vessel.
“I’m personally very confident,” William Barnes, 3H Evaporator Pot recovery manager for SRR, told the board. “We’ve got about a 95-percent chance” of success, he added, with the caveat that this was only his personal odds-making and not an official, mathematically derived estimate.
Savannah River Remediation plans to weld a 250-pound steel cap to the 3H Evaporator Pot’s leaky, conical bottom. The cap should be in place and the pot operational by Dec. 31, Barnes said. The company will practice the weld on a quarter-sized mock-up pot and a full-sized mock-up pot before attemptingto fix the real thing, Barnes said.
The weld, as with the leak inspection performed on the pot this year and last, will be performed robotically by workers stationed in a control room 100 feet away from the site in what Barnes called a command trailer. The cap, if it works as expected, is supposed to last 15 years.
SRR is now procuring both the robot and the cap, Barnes said.
There is no spare 3H Evaporator Pot, but SRR has not ruled out ordering one. Because the pot was expected to last 30 years, the company did not order a spare from Joseph Oat. That vendor did not reply to a request for comment this week.
Before it sprung a leak, the 3H pot could create about 1 million gallons of tank-farm space per year, Barnes said.
As for the cause of the leak, the steam jet inside the 3H pot churned a hole in the bottom of the vessel, according to the official. This steam jet, or lance, is a common feature of several evaporator pots at SRS, though none are as large or as powerful as the lance in the 3H vessel. A lance breaks up solid waste that settles at the bottom of a pot. This forceful churn of solids eventually wore holes in the bottom of 3H, Barnes said.
The waste from the leak was contained in the concrete cell in which the 3H Evaporator Pot sits, DOE and Savannah River Remediation have said. Neither the outside environment nor any personnel were contaminated.
