The U.S. Department of Energy is behind schedule to complete environmental and safety analyses at Savannah River Site, the federal facility near Augusta that is preparing to process and dispose of 25 million tons of nuclear materials starting in 2010.

In a study released Friday, the U.S. Government Accountability Office found that some required analyses have been delayed as much as two years by staffing shortages. The study, which was requested by the House Subcommitee on Energy and Water Development, also found that the program's cost estimates of $4.3 billion to $4.6 billion through 2019 leave out a half a billion dollars in possible expenses.

Another problem cited is the lack of storage remaining in the plant's 49 active underground tanks. The tanks, which now hold about 36.5 million gallons of radioactive waste, do not have the capacity to handle more waste that will be generated.

According to the study:

> A critical waste processing facility that will increase tank space has been delayed until at least 2012. It was scheduled to open in 2009.

> Twelve tanks have a history of leaks. The leaks were contained, but any new leaks, "though improbable," would delay disposal operations for about five years and cost about $2.25 billion.

> An evaporator needed to reduce the amount of water in the storage tanks could malfunction, delaying processing for up to a year at a cost of $550 million, according to the plant's risk management plan.

Much of the material planned for processing is already on site. Some of the waste, including about 8 tons of uranium, will arrive from five facilities that were part of the nation's Cold War nuclear weapons complex.

The uranium will be reprocessed and sold as fuel for Tennessee Valley Authority nuclear plants. According to DOE estimates, the U.S. Treasury will reap about $481 million in the transaction.

The Savannah River Site is also accepting weapons-grade plutonium from former bomb-making facilities as part of the federal government's plan to consolidate nuclear materials, said DOE spokesman James Giusti.

Giusti said no activities in the report are new to the plant, which has been chemically separating nuclear materials for nearly 50 years without major incident. The DOE contends it is operating the plant safely and with little environmental impact.

The study acknowledges the site has improved safety.

In a letter, DOE official Ines R. Triay said the plant manager this month directed the federal contractor to conduct the required safety analyses in time for processing spent nuclear fuel.

Glenn Carroll of Nuclear Watch South praised the report.

"The report emphasizes ongoing problems bedeviling the million-gallon high-level radioactive waste tanks which have been groaning at the seams for the last 50 years and lack of planning and analysis for future waste by DOE," she said.