The Department of Energy notified Washington and Oregon on Monday that a third Hanford waste tank is at serious risk of not being emptied by the deadline in the 2010 court-enforced consent decree.
DOE is required to have the 16 tanks in the group called the C Tank Farm emptied by the end of fiscal 2014, which is Sept. 30.
"Ecology is disappointed that the U.S. Department of Energy won't meet the requirement of the federal court order," said the Washington State Department of Ecology in a statement. "We are also disappointed that U.S. DOE did not inform us when they expect to complete this requirement."
The state continues to consider all options for addressing this and other consent decree requirements, the statement said.
The consent decree set deadlines for emptying waste from one group of Hanford's 149 leak-prone single shell tanks into sturdier double-shell tanks and also set deadlines for building and starting to operate the Hanford vitrification plant to treat the waste for disposal. DOE earlier notified the state that all remaining deadlines for the Hanford vitrification plant are at risk.
DOE and the state have until Oct. 5 to ask the federal court to intervene in consent decree requirements, following a period of negotiations that have so far been unsuccessful.
The state received the notification Monday on the third tank at risk, Tank C-111, where equipment issues have delayed retrieval of waste.
"While this delay is unfortunate, the department has completed retrievals of 13 single-shell tanks, and remains committed to completing tank retrievals in a manner that is protective of workers, the public and the environment," DOE said in a statement Monday.
The 13 tanks include 12 at C Farm and a 13th tank elsewhere at Hanford that is not covered by the consent decree.
That leaves four C Farm tanks not declared empty to regulatory standards with the deadline days away.
For one of those, Tank C-112, DOE has asked the state for a waiver. The consent decree allows the Sept. 30 deadline to be considered met if three technologies have been used to their limits to empty waste from a tank. The waste is left from the past production of weapons plutonium.
DOE notified the state in June 2013 that two of the tanks, C-102 and C-105, were at serious risk of not being emptied by the deadline, and that remains unchanged.
That announcement was followed by the notification Monday that the deadline also was at risk for Tank C-111, which has 35,000 gallons of waste remaining. Pumping was last done in November 2010 and has not resumed.
Sluicing systems are installed in the tank to spray liquid at high pressure on waste to help break it up and move it toward a pump in the center of the tank. But hydraulic hoses in the systems have leaks.
Tank C-105 is being emptied with a Mobile Arm Retrieval System, or MARS, which is the largest and most robust system used to retrieve waste in Hanford's underground tanks.
But this is the first time MARS has been used with vacuum attachments. Tank C-105 may have leaked waste in the past, so more commonly used sluicing systems that would add liquid to the tank are not appropriate.
Work with the MARS vacuum system is ongoing, but DOE officials have said that retrieval has been very slow, despite good performance when testing the system.
Tank C-102 has had 209,000 of 316,000 gallons of solid waste emptied from it. However, pumping has temporarily stopped to add a new sluicing system.
Work has stopped on Tank C-112, while DOE waits for a state decision on whether it has been emptied to regulatory standards. The tank has about 13,000 gallons of waste remaining after about 91,000 gallons of waste were removed. The goal is to get down to about 2,700 gallons of waste remaining, which is about 1 inch of waste if it were spread evenly across the bottom of the 530,000-gallon capacity tank.
Progress has been made at the C Tank Farm this year, with two C Farm tanks added to the list of those declared empty to regulatory requirements.
-- Annette Cary: 509-582-1533; email@example.com; Twitter: @HanfordNews