The state of Washington ordered the Department of Energy on Friday to start emptying radioactive liquid waste by Sept. 1 from a Hanford double-shell tank with an interior leak.
The state is expected to follow up that order as early as next week with an announcement on the court-enforced consent decree that sets deadlines for treating waste held in underground tanks.
The new Sept. 1 deadline to start emptying double-shell Tank AY-102 is at least 18 months sooner than DOE had planned to start work, according to a pumping plan it submitted to the state earlier this month.
DOE, pressed by the state to submit a plan to empty the tank, had proposed starting to remove waste no sooner than March 2016.
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It has known since October 2012 that the tank, the oldest of Hanford's 28 double-shell tanks, is leaking waste between its shells, but has proposed waiting to pump out liquid waste until it is ready to also pump out the radioactive sludge beneath it.
"Waiting another two years, at best, to initiate actions to address this hazardous condition is neither legally acceptable nor environmentally prudent," said Maia Bellon, director of the Washington State Department of Ecology, DOE's regulator for its underground waste tanks.
The state order also directs DOE to start removing sludge from the tank, in addition to liquids, by Dec. 1, 2015. Complete removal of enough waste to determine the cause of the leak is required by Dec. 1, 2016.
"The Department (of Energy) believes there are risks associated with pumping Tank AY-102 at this time," DOE said in a statement Friday. "The tank is not leaking into the environment, and there is no immediate threat to the public or the environment posed by AY-102."
Pumping liquid out of the tank now is technically feasible, but has risks because the liquid helps cool the waste, DOE said in the pumping plan it gave to the state. The sludge generates heat as it radioactively decays, and heat can increase corrosion rates in the tank and contribute to generating potentially flammable hydrogen gas.
Any action to remove liquid waste also might affect the rate at which the inner shell leaks, according to the plan.
The Defense Nuclear Facilities Safety Board told DOE in November that it should proceed with caution if it decides to empty liquid waste from the tank.
But the state said that leaving all the liquid waste in the tank poses a greater risk than pumping.
A leak in the primary tank creates a serious concern about a failure of the critical waste cooling system and an increased risk of a leak to the environment, according to the state.
The waste could potentially block ventilation channels between the bottom of the inner shell and the outer shell. The waste appears to be moving through those channels as it leaks out of the bottom of the inner shell, ending up on the floor of the circular space between the two tanks. The waste is contained within the outer shell, according to DOE.
The level of liquid waste in the tank already has declined 18 inches, or about 50,000 gallons, since August 2012 because of evaporation, according to DOE. It has proposed continuing to reduce the liquid level through evaporation. The tank has about 850,000 gallons of waste -- about 55 inches of sludge topped with about 235 inches of liquid.
The state is ordering that liquid be dropped only to 96 inches above the sludge to maintain safety in the tank, said Dieter Bohrmann, Ecology spokesman. That still would allow about 350,000 gallons of liquid waste to be removed.
"We believe it can be done safely and that any waste that can be removed now is going to reduce future risk," Bohrmann said.
The order requires DOE to immediately inform the state if any safety issues do arise after pumping has begun. If pumping is stopped to address a concern, DOE must provide a recovery plan within 30 days that includes a schedule for restarting pumping.
The state also has ordered DOE to provide a contingency plan for safely managing any worsening conditions, such as an increase in the rate of leaking or blockage of ventilation channels.
DOE has the infrastructure in place to immediately begin pumping liquid waste from the tank, but the state wants it first to isolate the tank from the rest of the double-shell tank system to prevent more waste from entering the tank. DOE has said that will take four months.
DOE has 30 days to appeal the state's order before it takes effect and four more months brings the deadline for the start of pumping to Sept. 1, Bohrmann said.
The order issued Friday followed months of discussions between the state and DOE plus its contractor. In June, DOE delivered its initial pumping plan to the state, saying that it did not plan to remove any waste from the tank unless conditions change. Pumping was not necessary to prevent a release of waste into the ground, it said.
That was not acceptable to the state, which demanded a new plan. DOE responded with a second pumping plan that called for starting installation of infrastructure to remove sludge from the tank but not removing liquid or sludge for at least two years. DOE already has started engineering and purchasing work to remove sludge from the tank when it is appropriate, DOE said Friday.
The matter gained more urgency for the state when, days before that second pumping plan was released, DOE discovered waste in a third place between the shells of Tank AY-102.
After months of discussions, it is clear that the federal government is not willing to address the regulatory requirements to remove the waste in a timely manner, the state said in a statement Friday.
In addition to removing waste, the state is requiring DOE to submit a report within 90 days evaluating the integrity of Tank AY-102's outer shell.
It also is ordering DOE to take monthly samples of liquid from the tank's leak detection pit and to perform weekly video inspections of the leaked waste and monthly video inspections of the space between the tank's shells.
DOE said Friday that it was disappointed that the state issued the order to pump Tank AY-102 without advance notice, despite the energy secretary flying to Olympia this week to discuss Hanford tank issues with Gov. Jay Inslee.
Inslee said the draft cleanup plan shared by Energy Secretary Ernest Moniz lacked the comprehensiveness and level of detail the state has requested for months.
DOE has told the state that it is at risk of missing all the remaining deadlines in a court-enforced consent decree for the Hanford vitrification plant being built to treat up to 56 million gallons of waste in underground tanks.
State Attorney General Bob Ferguson said during a visit to the Tri-Cities before the meeting with Moniz that "the time comes when you have to explore legal options" and the state is close to that.
The state continues to assess its options on the consent decree, but an announcement could be made next week, Bohrmann said.
-- Annette Cary: 582-1533; firstname.lastname@example.org; Twitter: @HanfordNews