Jane Lerner

jlerner@lohud.com

An inspector may have found the source of elevated levels of radioactive tritium at Indian Point.

The tritium was found in last week in the ground water in monitoring wells at the nuclear power plant.

Pipes from a storage tank apparently are leaking.

Authorities say the leak poses no danger to the public. The water is not used for drinking.

BUCHANAN - An inspector armed with a flashlight who crawled into the basement of a building near a water storage tank at the Indian Point nuclear power plant late last week might have found the source of elevated tritium levels detected in groundwater on the site.

"He saw leakage that supports the theory that the water came from water storage tank," Neil Sheehan, Nuclear Regulatory Commission spokesperson, said Friday.

The leak appeared in a pipe tunnel in a basement of a building that contains the spent fuel pool that was using a filtering system used to clean water from the Indian Point Unit 2 refueling water storage tank. Inspectors will continue to search for the exact path that the leak is taking.

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If further inspections confirm that pipes connected to the storage tank are leaking, that would explain the elevated tritium levels, Sheehan said.

The next step would be for Indian Point to figure out exactly where the pipe is leaking and fix it, he said. The filtering operation has been halted. But the plant is continuing to operate.

On Wednesday Entergy, the company that owns Indian Point, said the highest concentration of elevated tritium levels had increased by about 80 percent from the first test to the second, "fluctuations that can be expected as the material migrates."

Entergy spokesperson Jerry Nappi said on Saturday, though, that the groundwater monitoring well that had increased by 80 percent was back down to its initial elevated level from the first sample, which was expected.

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The NRC will closely watch tritium levels in the 40 monitoring wells on the Indian Point property, focusing on the wells closest to the building where the suspected leak occurred. Decreasing levels would show that the leak has been fixed.

And Entergy will still owe regulators an explanation of why the leak occurred and how such mishaps will be prevented in the future.

"All nuclear power plants are allowed to release radioactive liquid and gases but they have to do it in a very controlled and precise manner," Sheehan said. "An uncontrolled, unmonitored pathway to the environment — in this case the Hudson River — is unacceptable."

The NRC investigated a similar leak at the plant almost two years ago. In April 2014 Indian Point Unit 2 reported a leak of 687,000 picocuries per liter, Sheehan said.

"To put that into perspective, the EPA safe drinking water limit for tritium is 20,000 picocuries per liter," he said. "However, groundwater at Indian Point is not used for drinking-water purposes."

Entergy determined that leak occurred after a refueling outage, a procedure that the company said is likely at the root of the latest leak, as well.

Sheehan said the 2014 leak involved the draindown of the containment building spray header, when reactor coolant overflowed a floor drain on the 51-foot elevation of the pipe penetration building and leaked through a floor or wall seam to the ground.

In May 2015 the NRC went back and inspected Entergy's assessment of the leak. The NRC issued a "green" violation, meaning very low safety significance, to the company "for failing to evaluate the changing of the refueling operation to drain the containment spray system to a floor drain in the Unit 2 Auxiliary Building and ensuring that the temporary drainage arrangement did not result in a leak to groundwater," Sheehan said.

It is too early to draw conclusions from the most recent leak, but Entergy has pledged its cooperation.

This leak comes at a particularly sensitive time for Indian Point, which is in the midst of hearings to determine if the plant's license will be renewed. The elevated tritium levels comes soon after the plant in Northern Westchester had a series of unplanned shutdowns.

Lawmakers throughout the Lower Hudson Valley as well as Gov. Andrew Cuomo have called for the aging plant to be shut down.

Entergy officials contend that the nuclear power plant, which provides about 30 percent of the power used by New York City, is safe.

Even if elevated tritium levels reach the Hudson River, it won't cause a health risk or upset the delicate balance of the waterway, experts said.

“It’s absolutely not a biological or environmental concern,” said John J. Kelly of Garnerville, a certified health physicist, who retired as director of licensing for the Indian Point and other nuclear plants in the Northeast.

Tritium is in the environment all around us, he said. Tritium is a naturally occurring radioactive form of hydrogen produced in the atmosphere.

Most of the tritium produced in nuclear power plants stems from a chemical, known as boron, absorbing neutrons from the plant's chain reaction. Nuclear reactors use boron, which absorbs neutrons, to help control the chain reaction.

The NRC inspector saw boron crystals in the pipe tunnel where the suspected leak occurred.

The fact that tritium was discharged accidentally from Indian Point is the biggest concern, Kelly said.

"It's more of a regulatory problem than an environmental problem," he said.

Journal News/lohud reporter Matthew Spillane contributed to this story.

Twitter: @JaneLernerNY