The state of Washington has agreed to give the Department of Energy 18 more months to start emptying radioactive waste from a Hanford double-shell tank with a leak between its shells.
The state had required DOE to start emptying waste Sept. 1 from Tank AY-102, which did not happen.
It now agrees with DOE that more time is needed to prepare for the start of retrieval to prevent the creation of possible hazardous conditions within the tank.
“Modeling demonstrated that health and safety considerations outweigh potential environmental risks,” said Jane Hedges, manager of the Washington State Department of Ecology’s Nuclear Waste Program.
DOE and its contractor Washington River Protection Solutions have the infrastructure in place to start retrieving the liquid waste in the tank. As of this spring, the tank had 235 inches of liquid waste sitting above 55 inches of waste in the form of sludge.The liquid helps cool the sludge, which generates heat.
But DOE had told the state that it would not have equipment in place and be prepared to start also removing the sludge any sooner than March 2016. It was concerned about emptying significant amounts of liquid waste long before sludge would be retrieved, saying if the sludge heated up more flammable gas could be generated and the waste could corrode the tank.
It backed up that concern by modeling what would happen within the tank if liquid was pumped from it. The modeling was recommended by the Defense Nuclear Facilities Safety Board after the state issued an order in March requiring DOE to start liquid waste retrieval this month.
Modeling showed that liquid removal was a safety concern, Hedges said. If the ventilation system in the tank were to fail after liquid had been pumped, the waste could heat up quickly. Tank ventilation systems have failed in the past, she said.
Now DOE will be allowed to wait until shortly before pumping sludge to start pumping liquid waste from the double shell tank, according to a settlement agreement released Monday that will be filed with the state Pollution Control Hearings Board.
In addition, DOE went over its detailed work plans to prepare to empty the sludge from the tank with state experts, who agreed that the DOE needed more time to get infrastructure in place to empty sludge.
The state also agreed to give DOE three more months to finishing pumping waste from the tank, extending that deadline from Dec. 1, 2016, to March 4, 2017.
DOE has known since October 2012 that Tank AY-102, the oldest of Hanford’s 28 double-shell tanks, had an interior leak. When DOE had not made a commitment to start removing waste by March of this year, the state issued an order requiring DOE to start emptying the tank this month.
Because of the delay now being allowed to start emptying liquid waste from the tank, the state is requiring robust contingency planning, Hedges said.
DOE has 30 days to submit a plan to the state on how it will respond and recover from any worsening conditions in the tank.Now the waste is believed to be contained within the shells of the tank, rather than leaking into the soil beneath the underground tank. DOE has estimated that the tank, which has a capacity of 1 million gallons, is losing about 30 ounces of waste a week from its inner tank.
The state also is requiring continued monitoring of conditions within the primary tank, the secondary tank and the leak detection pit underneath the tank.
The agreement settles DOE’s appeal of the March state order, but sets penalties if DOE misses deadlines in the agreement.Potential penalties range from $500 per day for missing the deadline to supply the contingency plan or for other delays in providing inspection reports or notifications of safety issues.
Failing to start retrieving liquid waste from the tank by March 4, 2016, could result in a fine of $5,000 for the first week of delay, increasing to $7,500 for each week after that.
DOE and its contractor are working to be ready to start retrieving waste by then, if not sooner, DOE said in a statement.
The agreement was criticized by Heart of America Northwest, a Seattle-based Hanford watchdog group.
It said it had “grave concerns” about allowing DOE more time to start emptying Tank AY-102.
“Federal and state laws require that leaking tanks of any toxic waste must be emptied immediately,” said the group’s executive director, Gerald Pollet.
The state should have penalized DOE for its failure to start emptying the tank, after knowing it had an interior leak almost two years ago, it said.
-- Annette Cary: 509-582-1533; email@example.com; Twitter: @HanfordNews