A temporary zone was set up Feb. 28 because of the "increased risk that subversive activity could be launched by vessels or persons in close proximity" to the plant. But that zone, roughly 300 by 500 yards, is only closed to boats and swimmers until March 2003.

The Coast Guard on Friday published notice of its intent to make the zone permanent, opening a 90-day public comment period on the plan.

Operators of the nuclear power plant said they supported both the original closing and the move to make it permanent.

"We totally support a permanent buoy and any other measures that the Coast Guard may take to ensure the security of the plant," said Angela Walters, a spokeswoman for Constellation Energy Group, which owns the plant.

Walters said that the plant "works in close cooperation and communication with all enforcement agencies."

Coast Guard Lt. Dulani Woods said that there have been no reported violations of the security zone since it was established in February.

No one is allowed to enter the zone without prior permission from the Coast Guard captain or the captain of the Port of Baltimore. The Maryland Natural Resources Police are helping to patrol the area.

The Natural Resources Police commander for the Southern Region, which includes Calvert County, where the plant is located, said the waters around the plant were popular with fishermen and charter boats before the security zone was put in place.

But Lt. Richard Gardner also said that a public awareness campaign by the Coast Guard appeared to have successfully alerted boaters to the security zone. He said that the zone is heavily marked with "restricted area" buoys to deter anyone who was not already aware of the closure.

Not only have there been no violations of he security zone, but both Woods and Gardner said that they have received no negative feedback from those who may have fished or boated in the waters before the area was restricted.

That may be because they support the measure. Trevor Richards, president of the nearby Spring Cove Marina, said none of his tenants have mentioned the security zone.

"I think everybody's pretty supportive," he said.