On Thursday, the Union of Concerned Scientists called new attention to the leak at Indian Point , which is in a lining in the refueling cavity that is meant to stop leakage of radioactive materials in the event of an earthquake.
"NRC inspectors at Indian Point recently found that the liner has been leaking 2 to 20 gallons per minute since at least 1993 and that the plant owner has not yet delivered on repeated promises to fix the leak," said the activist group in a report. "That means the device installed to prevent leakage after an earthquake is leaking before an earthquake even occurs."
"By allowing this reactor to continue operating with equipment that cannot perform its only safety function, the NRC is putting people living around Indian Point at elevated and undue risk," the report says.
A spokesperson for Entergy said the container that is leaking is only filled during refueling, which occurs every two years, and leakage from the structure is captured and pumped out.
"This is something we have been aware of and the NRC is aware of, and there are no safety issues with it," the spokesman said. "There is no leak of fuel."
But Indian Point's safety issues have not been confined to a single leak. In 2005, Entergy reported leakage in the spent fuel pool of reactor two, resulting in the emission of strontium and tritium. There was leakage from the spent fuel pool in reactor one in 2008.
In 2009, 100,000 gallons of water contaminated with trace amounts of tritium leaked out through a broken pipe. Indian Point is one of about two-dozen plants in the U.S. that have reported tritium leaks. The NRC noted that the amount of tritium was well below the level allowed to be released.
In 2010, the state denied Entergy's request for water-quality certification at the plant, saying that Indian Point's two operating units violate state law and the federal Clean Water Act because they kill close to 1 billion marine organisms annually, including an endangered sturgeon, while consuming 2.5 billion gallons of water per day.
Even skeptical scientists acknowledge, however, that so far, the environmental concerns at Indian Point and other aging reactors around the country fall short of the potential for catastrophe.
"The chances of a disaster at a nuclear plant are low," the Union of Concerned Scientists noted. "When the NRC finds safety problems and ensures that owners address them -- as happened last year at Oconee (Georgia), Browns Ferry (Alabama), and Kewaunee (Wisconsin) -- it keeps the risk posed by nuclear power to workers and the public as low as practical. But when the NRC tolerates unresolved safety problems -- as it did last year at Peach Bottom (Pennsylvania), Indian Point, and Vermont Yankee -- this lax oversight allows that risk to rise. The more owners sweep safety problems under the rug and the longer safety problems remain uncorrected, the higher the risk climbs."