The Department of Energy has decided to close the oldest double-shell tank at the Hanford Nuclear Reservation. The department says that Tank AY-102 has widespread damage and should not be repaired. The Tri-City Herald reports: DOE was required by Ecology, a regulator for Hanford's tanks storing radioactive and chemical waste, to empty enough waste from the tank to determine the cause of the leak by spring 2017. DOE confirmed in 2012 that waste from the inner shell of the tank was slowly leaking into the space between its inner and outer shells. No waste is known to have breached the outer shell to contaminate the soil beneath the tank. One of the goals of the inspection was to decide whether the tank could be repaired and returned to service, a scenario that appeared unlikely. Hanford has just 27 double-shell tanks, excluding Tank AY-102, to hold waste emptied from 149 leak-prone single shell tanks until the waste can be treated for disposal. Plans call for glassifying much of the waste at the vitrification plant under construction at Hanford. The waste is left from World War II and Cold War production of plutonium for the nation's nuclear weapons program.