A radioactive isotope has been found at high levels in groundwater at the North Anna nuclear power plant in Virginia.
Tritium is a radioactive isotope of hydrogen, and it's being found at twice the level the federal government says is acceptable in drinking water. The Nuclear Regulatory Commission says those levels are not a hazard to the public.
Dominion Virginia Power is trying to figure out where the tritium is coming from. A company spokesman says the reactors are not the source of the leak, and that contaminated water is not moving off site.
Dominion told the Nuclear Regulatory Commission that there's no evidence the leak is related to last year's 5.8 magnitude earthquake.