The Hanford Tri-Party Agencies have tentatively agreed to delay legal deadlines for finishing cleanup work on the first group of Hanford’s 149 single-shell waste storage tanks.
Hanford workers have emptied 16 of the nuclear reservation’s underground single-shell tanks to regulatory standards, moving their mix of radioactive and hazardous chemical waste to newer double-shell tanks for safer storage until it can be treated for disposal.
But the emptied tanks still must be either removed from the ground or, as the Department of Energy has indicated it prefers, filled with grout and covered with a cap to make sure precipitation does not reach contamination in and around the tank and carry it deeper toward groundwater.
The tanks have complicated systems of piping and some have contaminated soil from spills or waste leaks that will be included in the cleanup plans.
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Whether removed or filled with grout and left in place, the tanks will be permanently closed.
“It’s really exciting to be talking about closing tanks,” said John Price, the Washington State Department of Ecology’s Tri-Party Agreement section manager.
The Department of Energy would be required to submit plans originally due in September 2015 in March 2017.
Getting to this point has been a long, difficult process since the Tri-Party Agreement was signed in 1989, he said. The agreement sets deadlines for Hanford nuclear reservation cleanup.
It was not until the 2000s that an agreement was reached to use the 16 tanks of the C tank farm to demonstrate emptying tanks and then completing cleanup by closing the tanks.
DOE faced a deadline in September 2015 to prepare a three-part plan for closing Hanford’s underground tanks and submit it to the Department of Ecology, a regulator on the project and one of the Tri-Party Agencies. DOE gave the state one report, an overall plan for closing all single-shell tanks.
But it did not submit reports covering how it would complete cleanup and close the C tank farm or and detailed, pipe-by-pipe plans on how it would close individual tanks within C farm.
At the time DOE had not finished an analysis of the risk, including from radioactive and hazardous chemical contamination, left at the C tank farm. About 100,000 gallons of radioactive waste has spilled or leaked there since the first tank was built in 1946.
The tanks hold waste left from past work to chemically separate plutonium from irradiated uranium fuel for use in the nation’s nuclear weapons program.
Under the proposed new deadlines for the Tri-Party Agreement, a deadline to have all tanks in the C tank farm closed in June 2019 will be replaced with a later deadline based on the proposed schedule DOE submits.
A 2019 deadline for closure of C Farm tanks would be reset after the Department of Energy submits its closure plans.
The revised consent decree deadlines issued in federal court in March do not require all tanks in the C tank farm to be emptied until 2024. Now 15 of the 16 C tanks, plus a tank in another farm, have been emptied to regulatory standards.
The deadline to have the remaining two parts of the plan filed is the end of March 2017. DOE must submit a plan for closure of the entire C tank farm, along with a schedule for the work, which will include the dates it expects to start closure of Hanford tanks. Target dates will be converted to enforceable schedules, according to the proposed agreement revisions.
In addition, DOE must submit detailed plans for the four smaller tanks in the C tank farm.
The four smaller tanks, all emptied, have a capacity of 55,000 gallons each and the larger tanks were built to hold up to 530,000 gallons of waste each.
The proposed changes establish an incremental approach to tank closure, according to the Tri-Party Agencies, which include DOE, Ecology and the U.S. Environmental Protection Agency.
Lessons learned from preparing the closure plan for the first four tanks can be applied to the remaining 12 in the C tank farm, according to the agencies.
The new deadlines also will allow DOE to demonstrate progress toward closing the entire C tank farm, according to the agencies.
They will consider public comment before revising the Tri-Party Agreement. Public comment will open Dec. 12 and continue through Feb. 3. Information on submitting comments will be listed on each day of the Hanford calendar through Feb. 3 at hanford.gov.