BUCHANAN — Federal nuclear regulators plan to inspect new samples of underground water at Indian Point today after the nuclear plants’ owner said that tiny amounts of radioactive tritium and strontium-90 appear to be seeping into the Hudson River.

Both radioactive isotopes are byproducts of nuclear reactor operations, but federal regulators and local emergency officials say there is no threat to public safety now because the levels detected were near or below amounts allowed for safe drinking water.

“They’ve taken samples along the riverfront, and they’re getting zeros there,” said Neil Sheehan, a spokesman for the Nuclear Regulatory Commission. “But there is a great dilution factor once you get to the river.”

Entergy Nuclear Northeast, the owners of Indian Point, released the tritium results yesterday at a biweekly telephone conference call including county emergency officials, state and federal regulators, and representatives of New York’s two U.S. senators.

Entergy spokesman Jim Steets said the state Department of Health found the presence of strontium-90 after analyzing split samples from some wells dug to test for tritium.

Company and public officials say both radioactive materials could be coming from a leak in the 400,000-gallon, 40-foot-deep spent- fuel pool near Indian Point 2, which was found during excavation work at the site in August.

Company officials said the leak never reached more than 2 liters a day, was quickly contained and has since stopped. They have not, however, ruled out that the pool has other leaks or the possibility that the water moving underground now might have been trapped more than a decade ago during an earlier leak.

There is no way to effectively monitor how much water goes in and out of the tank on a regular basis, company officials said, because a good deal of moisture is lost to evaporation. The company is continuing its search for other leaks in the tank, which has walls that are 6 feet thick.

To determine the reach of the radioactive water underground, Entergy has dug 19 wells in a network surrounding the spent-fuel pool. The company expects to dig 14 more before taking steps to stem the flow of underground water.

Sheehan said federal regulators were satisfied with the pace of the drilling and monitoring work. Entergy officials have estimated it will take as much as another year to finish.

The NRC agreed that more testing should be done, Sheehan said, because doing any remediation work now underground could jeopardize efforts to figure out the extent of the leak.

Anthony Sutton, Westchester’s commissioner of emergency services, said he was comfortable that public safety wasn’t a concern, but added that without the leak showing up during the summer excavation, there might not have been any indication that radioactive materials were moving underground.

“Would this have gone undetected had it not been discovered during construction?” Sutton asked rhetorically yesterday. “Shouldn’t there be this kind of well monitoring throughout the site on a normal basis?”

What are isotopes?

• Tritium is a radioactive isotope of the element hydrogen. It is naturally produced in the upper atmosphere when cosmic rays strike air molecules and as a byproduct in nuclear reactors that produce electricity. Exposure to it and other radiation increases the risk of developing cancer.

• Strontium-90 is a fission byproduct of uranium and plutonium. Large amounts were produced in the 1950s and 1960s during atmospheric nuclear weapons tests.

Source: Environmental Protection Agency“

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