Radioactive tritium has been found in a water sample from a monitoring well at the Entergy Corp.-owned 620 MW Vermont Yankee nuclear power plant, just a year after another related incident.

The finding came from a well installed in November 2010 to monitor for tritium. It is not a drinking well and does not pose a risk to public health and safety.

The amount of tritium found was 9,200 picocuries per liter, which is below the Nuclear Regulatory Commission’s required level to report tritium findings of 30,000 picocuries per liter and the U.S. Environmental Protection Agency’s standard for permissible levels of tritium in drinking water of 20,000 picocuries per liter, Entergy said.

Over the past year, the company has found tritium in water samples that was caused by the migration of tritiated water released by the Januaryleak in the advanced off gas system pipe tunnel which was sealed and repaired earlier this year.

Entergy is now trying to get a license extension to operate Vermont Yankee for another 20 years. The reactor is due to shut down in 2012 unless the operation license is renewed.

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