RICHLAND — There is a slow leak in the oldest double-shell waste tank at the Hanford nuclear reservation that's allowing highly radioactive and hazardous waste to leak into the space between the inner and outer shells, the federal Department of Energy said Monday.
No waste is believed to have leaked from the outer shell into the soil beneath the underground tank on the south-central Washington reservation, the agency said.
Earlier testing showed that some of the material seen between the two walls of the tank was radioactive waste. Now DOE has confirmed a leak. While the exact amount isn't known, the agency said perhaps a couple tablespoons of additional waste were seen between the two tank walls between Thursday and Sunday.
The tank is one of 28 double-shell containers used to hold waste from older, leak-prone single-shell tanks. They hold 56 million gallons of radioactive waste from the past production of weapons plutonium until it can be treated for disposal.
The tank is roughly 40 years old and contains about 850,000 gallons of sludge and liquid waste.
Plans call for continued twice-weekly visual inspections using cameras and regular checks of liquid levels inside the primary tank, said Tom Fletcher, assistant manager for the Tank Farms Project.
Fletcher added that his people are "working collaboratively" with the state Ecology Department to determine what to do next and to "ensure that we are effectively protecting the public and the environment."