Six of Hanford’s underground waste storage tanks are leaking radioactive and hazardous chemical waste into the ground, Washington Gov. Jay Inslee announced Friday afternoon.
Last week the state said one single-shell tank was leaking up to 300 gallons of waste a year. But after meeting Friday with Energy Secretary Steven Chu, Inslee now says five more are leaking.
Whether there could be more than six tanks leaking has not been determined, he said. Chu wants to personally study the data, according to the state of Washington.
The amount of the waste leaking from each tank varies. Several tanks date from the World War II era. Five were built in 1943-1944, and the sixth in the 1950s. Three are in tank farms other than the T Tank Farm, the grouping of 16 tanks where Tank T-111 was discovered to be leaking last week, Inslee said.
The discovery of additional leaking tanks “is disturbing news,” and raises more concerns about the condition of the single-shell tanks, the governor said.
There is no imminent health danger to the public from the leaks from the six tanks, Inslee said.
Some 67 tanks are believed to have leaked in the past. But none were known to be leaking until this month after the last of their pumpable liquids were removed in 2004, leaving sludge.
In fact, two of the newly discovered leaking tanks - Tanks T-203 and T-204 - had not been suspected of ever leaking before now, according to Suzanne Dahl of the Washington State Department of Ecology.
Data on the single-shell tank waste levels had been collected but not properly evaluated to catch the evidence of leaks, the governor said.
A new study to look an anomalies in tank levels was launched last year by DOE and led to the discovery of the leaking tanks.
Repairing the tanks is not an option, Inslee said.
A new system for removing waste from the tanks is needed, and there are questions about where the waste would go, he said. There are fast and slow alternatives, which he may be able to say more about next week.
Hanford has 28 double-shell tanks to hold waste emptied from 149 single-shell tanks. But even before news of new leaks broke, the tanks may have had inadequate space to meet legal requirements for Hanford cleanup, the governor said.
He called earlier this month for new double-shell tanks to be built, but said that would take five years or more.
DOE has previously said that 11 of Hanford’s 177 tanks have waste that could be considered transuranic waste -- waste contaminated with certain levels of plutonium -- and had considered sending them to the Waste Isolation Pilot Plant in New Mexico, the nation’s repository for transuranic waste.
Five of the six leaking single-shell tanks are among the 11 DOE has previously identified as possible transuranic waste.
Waste sent to New Mexico would not need to be treated first at the vitrification plant being built to treat up to 56 million gallons of waste held in underground tanks from the past production of plutonium.
However, the state of New Mexico would have to agree to a permit modification. Tank waste is currently barred from being sent there.
One of the just-discovered leaking tanks, Tank TY-105, is a 758,000-gallon-capacity tank. It has not been considered for potential designation as transuranic waste.
The other four tanks added to the list of current leakers Friday - tanks T-203, T-204, B-203 and B-204 - are smaller, with 55,000 gallon capacity each.
They are leaking at a suspected rate of about 15 gallons a year, Dahl said.
Tank T-111, the tank identified as a leaker last week, has a capacity of 530,000. It and Tank TY-105 are suspected of leaking up to 300 gallons a year.
The leaking likely has continued over several years, Dahl said.
Before 2004 an estimated 1 million gallons of waste leaked or spilled from the tanks and their distribution systems.
Some of that has reached the groundwater, but movement from central Hanford to the Columbia River, five miles away, is slow.
Although there is no immediate health threat, the federal government has moral and legal obligations to clean up Hanford, Inslee said.
Addressing the tank leaks by moving money from other Hanford projects is not acceptable to the state of Washington, he said.