Indian Point’s Unit 3 reactor has been shut down twice this month after workers discovered leaks that company officials say don’t pose a threat to public safety.
One of Indian Point’s two nuclear reactors resumed generating power Monday after a five-day shutdown that followed the discovery of a steam leak.
Unit 3 began generating power after inspectors with the federal Nuclear Regulatory Commission signed off on repairs made to piping on a water heater.
It was the second time this month that Unit 3, which is slated to power down for good when Indian Point closes in 2021, has been off line. The reactor was down for nine days after a water leak in a backup cooling system was discovered Sept. 7.
Indian Point’s owner, Louisiana-based Entergy, said both leaks occurred on the non-nuclear side of the building where Unit 3 is housed and there was never a risk of a radiation release or threat to public safety.
NRC spokesman Neil Sheehan said the back to back shutdowns are, at this point, not considered evidence of a deeper problem with the reactor’s reliability.
“We want to ensure that the company is being thorough when it comes to any repairs and exhaustive in working to understand what caused any leaks,” Sheehan said. “We have found that to be the case following the two recent Indian Point Unit 3 shutdowns, even though the forced outages were triggered by leaks involving different systems.”
But, Sheehan added, the NRC will continue to monitor developments while Entergy investigates the root cause for each failure.
“We will be interested to learn what Entergy’s further analyses show and whether there are any weaknesses with respect to the way these systems are monitored for signs of corrosion or other failure mechanisms,” Sheehan said.
The latest shutdown began the morning of Sept. 18 after a steam leak was discovered in the plant’s turbine building. Inspectors determined that a pipe 6 inches in diameter was thinned by “flow-accelerated corrosion.”
“Further metallurgical analysis will be performed,” Sheehan added. “Repairs were made to the piping and checks were conducted on other similar piping.”
By Monday morning the unit was generating electricity at 28 percent of its power, the NRC said. The power plant’s other working reactor, Unit 2, continued generating power through both shutdowns.
The first shutdown came after boron, boric acid in its white powder form, was discovered on a backup cooling system, known as the safety injection system. Boric acid is used to control reactivity in a nuclear reactor and its presence was indication of a water leak.
Last week, the NRC announced it had renewed Entergy’s operating licenses for the Buchanan power plant’s two reactors, following a review that began in 2007.
Unit 2’s license will be good through 2024 and Unit 3 through 2025, though the reactors will shut down in 2020 and 2021 respectively as part of a 2017 agreement with the state of New York.
The four-year license extension allows the reactors to produce power in the event of an emergency, which would include war, terrorism as well as sudden increased demand or sudden shortages in the energy supply.
“Indian Point is one of the most reliable electricity generating plants in New York state, and it repeatedly has been determined to be safely and securely operated,” Entergy’s chief nuclear officer Chris Bakken said last week.
By Thomas C. Zambito