ritium, a radioactive isotope, found in water at the bottom of six sampling wells on the Indian Point nuclear plants

Newsday.com: NRC chair pledges greater oversight of nuclear plant: "Entergy and the NRC said last week that low levels of tritium, a radioactive isotope, have been found in water at the bottom of six sampling wells on the Indian Point property in Buchanan, N.Y.

The tritium may be the result of a leak from Indian Point 2's spent fuel pool, first detected in August.

In one of the wells, the amount of tritium found was slightly above the federal standard permitted for drinking water. However, none of the wells, which are 20 to 30 feet deep, are used for drinking water or for anything other than sampling groundwater.

The water is believed to have leaked from a 40-foot-deep pool, which holds the highly radioactive fuel assemblies that have been used in the nuclear reactor."