Hanford deadline extended for radioactive waste tank farm caps

The Department of Energy was given three more years to build four large barriers over the ground at the Hanford tank farms to help contain spilled or leaked radioactive and hazardous chemical waste.

The DOE was required under the legally binding Tri-Party Agreement to have four more of the barriers, or caps, built a year from now.

But after more than a year of talks, the Washington state Department of Ecology agreed to extend the deadline. The new deadline requires the barriers by Oct. 31, 2020, and includes some interim deadlines to keep the DOE on track to meet the requirement.

Documents indicate that the unpredictable federal budgets and money spent to help protect Hanford workers from chemical vapors associated with waste in underground storage tanks contributed to the delay in planning and building the barriers.

The DOE previously built two barriers and is required to build four more. Two were supposed to be completed in 2015, another this year and the next one in 2017.

The DOE completed plans for the two barriers required to be constructed in 2015, but has not started building them.

The barriers – which can be built of a durable plastic product or modified asphalt – are the size of football fields or larger and act as an umbrella over contamination already in the ground.

They keep rain or snow melt from soaking into the waste plume and spreading it deeper into the ground. They are a temporary measure until a long-term solution is found for the underground contamination.

The Ecology Department issued a $5,000 fine against the federal DOE, accusing it of not letting the state know soon enough that it could not meet the Tri-Party Agreement schedule.

The DOE disputed that, and ultimately, the agencies agreed in late September to settle the matter with the DOE paying a $2,500 fine but not admitting fault. The agreement was reached to avoid the expense of litigation, according to a document signed by both agencies.

Documents say the DOE ran into troubles when its spending levels were capped in fiscal 2015 after Congress failed to pass a DOE budget. The budget remained flat at the fiscal 2014 level.

The DOE expected that more efficient operations would allow it to catch up before spring 2015, as it faced deadlines later in the year to have two of the four barriers constructed and a third designed.

Instead of catching up, the DOE faced increased expenses in the tank farms. Money was needed to study and improve chemical vapor protection for workers and to empty Tank AY-102, a double-shell tank with a waste leak between its shells.

The next two caps to be built are planned for the SX Tank Farm, because contamination is substantial and near the ground’s surface, according to the Ecology Department. The SX Tank Farm has 15 underground tanks, with 10 of them suspected of leaking in the past.

The location of the last two caps covered by the Tri-Party Agreement are not selected.

Initial monitoring results of the two barriers already built at the tank farms showed the soil underneath them was staying drier than soil without the caps.

With the caps appearing to be working, the Ecology Department is interested in increasing the size of additional barriers to cover more area, said John Price, of the department.

The DOE built the first cap, which was about the size of a football field, in 2007 over 10 tanks at the T Tank Farm, Hanford’s oldest group of waste tanks.

The cap – built of dirt covered with a synthetic fabric and then sprayed with a layer of polyurea – was planned to keep precipitation from reaching a waste plume from one of the largest waste leaks at the Hanford tank farm.

The cap was planned to cover ground where waste spread about 75 yards around underground waste Tank T-106 and 90 feet below it.

It was a fortuitous choice of locations. In 2013 Tank T-111, one of Hanford’s 149 single-shell tanks, was discovered to be dripping waste into the soil beneath it. The cap partially covers the area around Tank T-111.

The second tank farm cap, of asphalt modified with a polymer to make it weatherproof, was built in 2010. It covers all six tanks of the TY Tank Farm.