KITTERY — Reports of a fire aboard the USS Miami this morning were a false alarm, a spokeswoman for the Portsmouth Naval Shipyard said.

The nuclear sub was heavily damaged in a fire May 23, but the spokeswoman said the fire alarms that went off on the ship this morning shorly before 9 a.m. were faulty.

She said there was no fire and no smoke aboard the sub. Non-essential members of the crew were evacuated as a precaution, said the spokeswoman, Danna Eddy.

The Miami had been at the shipyard for about four months of a scheduled 20-month overhaul when a fire broke out in the forward half of the sub last month. The fire heavily damaged the control room, torpedo room and crew quarters.

The nuclear reactor, which is the located toward the stern of the sub, was not damaged and crew members continued to monitor it even as firefighters dealt with heat, heavy smoke and darkness in trying to put out the fire.

It took crews hours to get the fire under control and seven firefighters suffered minor injuries.

It was several days before Navy officials were able to go into the area where the fire had broken out to begin investigating the cause of the fire. The Navy has not said if they’ve determined the cause yet.

Rep. Chellie Pingree, D-Maine, who toured the Miami Tuesday, said the Navy’s preliminary estimate for repairing the ship is $400 million.

Navy officials have said they want to fix the Miami and return it to service because the size of the U.S. fleet has been shrinking in recent years.

It cost about $900 million to build the Miami, which was commissioned in 1990. New attack submarines cost about $2 billion.

Pingree is married to S. Donald Sussman, majority share owner of the Portland Press Herald/Maine Sunday Telegram.