Tanks holding millions of gallons of nuclear and chemical waste at the Hanford Nuclear Reservation are deteriorating at a faster rate than previously thought, according to a new report from the U.S. Government Accountability Office (GAO).

The GAO report was released today by Sen. Ron Wyden (D-Ore.), who is demanding the Department of Energy (DOE) develop a plan to address leaks and other tank issues. He said the DOE must act on the recommendations in the report instead of acknowledging them and then doing nothing, as it has done in the past.

"Agreeing to recommendations is one thing, implementing them is another thing entirely," Wyden said. "The DOE's 'watch-and-wait' strategy for these tanks leaking nuclear waste into the soil is completely unacceptable. I'm asking for a schedule and a plan of action within 90 days to implement the GAO's recommendations at Hanford."

Highlights of the report include new information on the number of older, single-shell tanks (SSTs) at Hanford that are experiencing what's called water intrusion – 14 as of the fall of 2014. Rain or ground water entering the tanks can cause a host of problems, including mobilizing the waste and giving monitors undependable levels of waste in the tank, making it difficult to detect leaks.

In addition, one of the SSTs (T-111) is leaking at a much higher rate than thought, some 640 gallons per year.

There are concerns the waste, which is leftover from decades of plutonium production at the 586-square-mile reservation in southeastern Washington, could leak through the aging tanks into the groundwater and the nearby Columbia River.

The report also found that several of the newer double-shell tanks (DSTs) share the same design flaws blamed for leaking in the interior wall of AY-102 – a DST found to be leaking in 2012.

DOE is in the process of developing a plant that can convert the radioactive waste into stable glass that can be safely stored for hundreds of years. That plant is years behind schedule, billions of dollars over budget and plagued by unresolved design and safety issues.

Critics, including Wyden, have demanded DOE develop a plan for dealing with the stored waste while those issues are resolved. The governors of Oregon and Washington have urged DOE to build additional storage tanks to hold the waste until the treatment plant is finished. The GAO report notes that DOE estimates building new tanks would take eight years and require $800 million in funding.

The DOE's acting assistant secretary for environmental management, Mark Whitney, responded to the report by saying DOE already has a plan to constantly monitor the tanks and respond to suspected leaks.

"This program includes the use of robotic ultrasound devices, corrosion monitoring probes, and remote video cameras for the DST," said Whitney in a written response to the report.

Hanford Challenge, a watchdog group dedicated to ensuring a safe and expeditious clean-up at the site, issued the following statement: "It has been obvious since the first double-shelled tank failed at Hanford in 2012 that new tanks were desperately needed at Hanford. However, local economic interests in the Tri-Cities have exerted political power with state Congressional representatives to block the construction of new tanks at Hanford. New tanks have been demanded by WA Governor Inslee, and Hanford has chosen to fight the State in federal court rather than comply. Washington State is at risk because Hanford has no plan if a new leak from a Hanford tank happens any time soon. There will be no available tank space left. There needs to be a different agency in charge of Hanford's cleanup – one not beholden to the contractors that benefit from delay, slowdowns, and cost overruns."

Read the full report and the Department of Energy's response.