This is what a Hanford underground tank looks like above the surface. Credit: John Stang
More huge, underground radioactive waste tanks could be needed at the Hanford nuclear reservation.
Earlier this month, the Hanford Advisory Board told the U.S.Department of Energy that the site's 28 double-shell waste tanks are nearing the end of their design lives and new ones need to be built. No one has a handle on how many new tanks would be needed, nor on how much they would cost. A 1995 estimate, likely outdated, speculated that constructing a 1-million-gallon tank could cost $100 million, although that number could be different today. No one has estimated yet how many new tanks would be needed.
The board's recommendation comes as the cost of Hanford's massive waste glassification complex threatens to creep up, while the the federal government faces potential cutbacks — including possibly at Hanford — if Congress cannot resolve its current budget impasse by Dec. 31. The Hanford board's position carries significant clout because it represents 32 Northwest constituencies covering the entire Hanford political spectrum from Tri-Cities business interests to Seattle and Portland environmental watchdog groups.
The bottom line is that any Hanford Advisory Board position has almost universal political support from across the Northwest.
This push to build new underground tanks stems from the Department of Energy confirming that 190 gallons to 520 gallons of radioactive fluids have leaked through the inner shell of one of Hanford's 28 double-shell tanks to settle at the bottom of the space between the inner and outer shells. Hanford speculates that the leak is near the bottom of the inner shell, possibly at a weld. The Tri-City Herald reported that the leak could have sprung as early as 2007.
The Energy Department and Washington's Department of Ecology said they will consider the board's recommendation to build new double-shell tanks, but have not reached any decisions. Hanford has a team studying the matter. Six double-shell tanks will be checked in the next six months to see if similar leaks are occurring, said Energy spokeswoman Lori Gamache.
Central Hanford holds 53 million gallons of highly radioactive liquids, sludges and gunk in 149 old single-shell underground tanks and 28 newer double-shell tanks. So far, 67 single-shell tanks are suspected of leaking more than 1 million gallons of radioactive liquids into the ground to seep toward the Columbia River. The 28 double-shell tanks have designed lives of roughly 40 years, which are now beginning to end. This is the first leak confirmed in a double-shell tank.
Hanford has been pumping wastes — radioactive chemical leftovers from creating plutonium for atomic bombs — from the single-shell tanks to the double-shell tanks. DOE's master plan is to build a complex to begin glassifying those wastes in 2019 and to finish the work by 2047. The original target to begin glassification was 1999, and then 2011, before 2019 became the deadline. The project has been haunted by design problems, unanswered engineering questions, many delays and a constantly increasing budget, which has grown from $4 billion to roughly $13 billion.
Dirk Dunning, a longtime nuclear materials specialist at Oregon's Department of Energy and chairman of the Hanford Advisory Board's tanks waste committee, said the board originally looked at whether new tanks would be needed in 1995. But the board decided it did not want DOE to siphon money away from the glassification project. Plus, in the 1990s, the board thought the glassification plant would be running before leaks would show up in the double-shell tanks, he said.
"The tanks have a finite life. … Things will eventually wear out," Dunning said.
Susan Leckband, a retired Hanford employee and interim vice-chairwoman of the Hanford Advisory Board, said, "Now that there's a leaker, its been brought to the forefront that these tanks are beyond their design lives."
The Oct. 22 confirmation of the first leak a double-shell tank — dubbed "Tank AY-102" — caused the board to push for new double-shell tanks at its Nov. 2 meeting in the Tri-Cities.
The board's Nov. 2 letter to the federal Energy Department and the state Ecology Department said no plans currently exist to deal with the double-shell tanks reaching the ends of their design lives or to deal with the wastes in those tanks. The letter said: "The remaining safety margins for these tanks against corrosion, stress, strain and earthquake is uncertain. … It appears that additional tank capacity is a necessary interim measure to protect the environment. However, building more tanks at Hanford does not delay the urgent need for tank waste treatment," which is the glassification plant under construction to begin working in 2019.
Another wrinkle is that the 28 double-shell tanks are almost filled with wastes, which leaves no place for AY-102's fluids and sludges to be pumped to if needed, Dunning said. However, the Energy Deparment does have emergency pumping equipment in place in case such a measure is needed, said state Ecology spokesman Dieter Bohrmann.
Also the chemical make-up of the wastes in each Hanford underground tank is different -— meaning complicated pumping, separating and blending are needed to get the wastes into the proper compositions to be glassified. Closing down leaking double-shell tanks decreases DOE's ability to juggle wastes accordingly to obtain the proper chemical and physical compisitions.
Dunning speculated that Hanford could look at installing tanks that are smaller than the 500,000-gallon to 1.2 -million-gallon range of the current underground tanks. Smaller tanks could be built whole or in sections elsewhere, spreading the work among several competing bidders to shrink the overall costs, Dunning theorized. Hanford currently accepts defunct submarine reactor compartments from Bremerton, which are barged up the Columbia River to Richland. Smaller tanks and sections of tanks could be transported to Hanford the same way, he suggested.
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