Washington (Platts)--7Apr2008

The US Nuclear Regulatory Commission said it is monitoring an "unusual
event" declared early Sunday at the Millstone 2 nuclear power plant in
Waterford, Connecticut, that led to the "likely" release of some low-level
radioactive gas.

The agency said an unusual event is the lowest of four levels of
emergency classification it used.

The NRC on Sunday said the plant's owner and operator Dominion made the
declaration at 1:17 pm (EDT) after it detected an increase in unidentified
leakage at the plant. Millstone 2, a pressurized-water reactor, was shut down
at the time for a scheduled refueling and maintenance outage.

The agency said that when "operators placed a system into service to
further cool down the plant, they observed increased reactor coolant system
leakage and an increasing level in an on-site water-storage tank." The agency
added that the "leakage between the reactor coolant system and the storage
tank was captured by the tank and therefore there was no liquid release to the
environment." The leakage to the tank has since been halted, NRC said.

The storage tank has a vent to the atmosphere, the NRC said, adding that
"some low-level radioactive gas was likely released through the tank vent."

The agency said it is independently evaluating any potential release and
radiological consequence.

The agency said it began formally monitoring the event at 2:30 pm Sunday.
Millstone 3, an adjoining pressurized-water reactor operated by Dominion, was
not affected by the event and continues to operate at 100% power.

Federal and state officials have been notified regarding the event.