SPOKANE, Wash. – There are “significant construction flaws” in some newer, double-walled storage tanks at a U.S. nuclear waste complex in Washington state which could lead to additional leaks, according to documents obtained by The Associated Press.
The tanks hold some of the worst radioactive waste at the most contaminated nuclear site in the country.
One of the 28 giant underground tanks at Hanford was found to be leaking in 2012. But subsequent surveys of other double-walled tanks performed for the U.S. Department of Energy by one of its Hanford contractors found at least six shared defects with the leaking tank that could lead to future leaks, the documents said. Thirteen additional tanks also might be compromised, according to the documents.
Hanford, built at the height of World War II as part of the Manhattan Project to build the atomic bomb, stores about two-thirds of the nation’s high-level radioactive waste. It contains high-level radioactive wastes from the production of plutonium for nuclear weapons. They are stored in 177 underground storage tanks, many of which date back to World War II and are single-walled models that have leaked. The 28 double-walled tanks were built from the 1960s to the 1980s.
Questions about the storage tanks jeopardize efforts to clean up radioactive waste at the site. Those efforts already cost taxpayers about $2 billion a year.
“It is time for the Department (of Energy) to stop hiding the ball and pretending that the situation at Hanford is being effectively managed,” Sen. Ron Wyden wrote this week in a letter to Energy Secretary Ernest Moniz.
Officials have said the leaking materials pose no immediate risk to public safety or the environment because it would take perhaps years for the chemicals to reach groundwater.
Energy Department officials said the agency continues to make thorough inspections of the tanks and has increased the frequency of those inspections.
“They used to be reviewed every five to seven years,” said Tom Fletcher, the Energy Department’s assistant manager for tank farms. “Now we are moving to a three-year time frame.”
The department is in the process of inspecting the final eight double-walled tanks at Hanford that have not been analyzed since the leak was detected in late 2012, Fletcher said Friday.
No new leaks have been found, he said.
Tom Carpenter of the citizen watchdog group Hanford Challenge said he wasn’t surprised that more of the double-walled tanks are in danger of leaking.
“These tanks have an engineered design life, and we are reaching the end,” Carpenter said. “It’s bad planning that they don’t have new tanks up and running.”
While new tanks are expensive, cleaning up a leak is more expensive, he added.
Current plans call for transferring wastes from leaking single-walled tanks to the newer and bigger double-walled tanks, where the waste will be stored while a $13 billion plant for treating the waste is constructed. But the treatment plant is plagued with design problems, and construction has stalled.
The situation did not appear dire until the news in October 2012 that the oldest of the double-walled tanks, called AY-102, had leaked, becoming the first of those 28 tanks to do so.
At the time, the Energy Department blamed construction problems with the particular tank and said it “seems unlikely” that the other double-walled tanks would leak.
However, Wyden said engineering reviews of six other double-walled tanks “found significant construction flaws in those six tanks essentially similar to those at the leaking tank.”
For instance, one tank was found to have bulging “in the primary and secondary bottoms,” according to the documents obtained through Wyden’s office. The tank also had a high number of welds that were rejected by inspectors and done again during its construction.
Additionally, a review of 13 other double-walled tanks found they were in better shape than the leaker. “But construction issues identified for these tanks, such as weld rejection rates, are cause for concern” and raise “uncertainty of long-term tank integrity,” Wyden wrote.
That means that 20 of the 28 double-walled tanks at Hanford raise some level of concern.
Wyden asked the Energy Department to respond with an action plan in 45 days.