WATERFORD, Conn. (AP) - Nuclear power plants across the United States are building or expanding storage facilities to hold their spent fuel - radioactive waste that by now was supposed to be on its way to a national dump.
The steel and concrete containers used to store the waste on-site were envisioned as only a short-term solution when introduced in the 1980s. Now they are the subject of reviews by industry and government to determine how they might hold up - if needed - for decades or longer.
With nowhere else to put its nuclear waste, the Millstone Power Station overlooking Long Island Sound is sealing it up in massive steel canisters on what used to be a parking lot. The storage pad, first built in 2005, was recently expanded to make room for seven times as many canisters filled with spent fuel.
Dan Steward, the first selectman in Waterford, which hosts Millstone, said he raises the issue every chance he can with Connecticut's congressional members.
"We do not want to become a nuclear waste site as a community," Steward said.
The government is pursuing a new plan for nuclear waste storage, hoping to break an impasse left by the collapse of a proposal for Nevada's Yucca Mountain. The Energy Department says it expects other states will compete for a repository, and the accompanying economic benefits, and it's already heard from potential hosts in New Mexico, Texas and Mississippi. But the plan faces hurdles including a need for new legislation that has stalled in Congress.
So plants are preparing to keep the high-level nuclear waste in their backyards indefinitely. Most of it remains in pools, which cool the spent fuel for several years once it comes out of the reactors. But with the pools at or nearing capacity, the majority is expected within a decade to be held in dry casks, or canisters, which are used in 34 states. Only three of the 62 commercial nuclear sites in the U.S. have yet to announce plans to build their own.
In the past few years since the Yucca Mountain plan was abandoned, the government and industry have opened studies to address unanswered questions about the long-term performance of dry cask storage. The Nuclear Regulatory Commission in 2011 began offering 40-year license renewals for casks, up from 20-year intervals. The tests are focusing on how to monitor degradation inside the canisters, environmental requirements for storage sites, and how well the canisters hold up with "high burnup," or longer-burning fuels that are now widely used by American plants.
"Now that we've shown that the national policy is shifting, we're having to relook at these systems to make sure they still meet the regulations for longer and longer periods of time," said Eric Benner, an NRC official who has served as the inspections branch chief with its spent fuel storage division.
At Millstone, 19 canisters loaded with spent fuel are arrayed on a concrete pad, which was expanded in October to make room for as many as 135 canisters by 2045. The canisters, which are cooled by air circulation, seal the waste with inert gas inside an inner chamber and are themselves loaded into concrete modules. Workers regularly inspect temperature gauges and, during the winter, shovel snow off the vents.
Millstone's low-level nuclear waste is shipped to a disposal facility in Barnwell, South Carolina.
The spent fuel is piling up at a rate of about 2,200 tons a year at U.S. power-plant sites. The industry and government decline to say how much waste is currently stored at individual plants. The U.S. nuclear industry had 69,720 tons of uranium waste as of May 2013, with 49,620 tons in pools and 20,100 in dry storage, according to the Nuclear Energy Institute industry group.
Spent nuclear fuel is about 95 percent uranium. About 1 percent is other heavy elements such as curium, americium and plutonium-239. Each has an extremely long half-life - some take hundreds of thousands of years to lose all of their radioactive potency.
Watchdog groups say the dry storage poses fewer safety concerns than the reactors themselves, and many have pushed for spent fuel to be transferred more quickly from the pools. Heavy security is in place to deter sabotage by terrorists.
The administration's strategy calls for an interim storage facility by 2025 and a geologic repository by 2048.
Peter Lyons, an assistant secretary for nuclear energy at the U.S. Energy Department, said it cannot make plans for individual sites until the passage of legislation creating a new framework for waste policy. But he said the groups in southeastern New Mexico, western Texas and Mississippi are only the most public of potential hosts to express interest in taking in high-level waste.
The idea for the interim facility is to take spent fuel left behind from reactors that have already shut down, as is the case at sites in California, Maine, Massachusetts, Michigan, Wisconsin, Connecticut, Colorado and Oregon.