What happened at the Davis-Besse nuclear generating facility

The Davis-Besse pressurized water reactor was taken off line on 16 February 2002 for routine maintenance. After a hole was discovered in the reactor vessel head it was kept shut down for repairs. It did not return to producing electricity steadily until two years later, 4 April 2004! What happened, how it might have happened, how it was fixed, whether there was cause for alarm among the general public, and what effects it had on FirstEnergy will be discussed.