Federal regulators are proposing a $65,000 fine against the operator of a York County nuclear plant where security guards routinely napped on the job.

The Nuclear Regulatory Commission announced the fine against Exelon Nuclear on Tuesday after completing a special investigation of the Peach Bottom plant.

The NRC says multiple guards were "deliberately inattentive" on several occasions, and the incidents weren't reported to plant supervisors.

Exelon ended its contract with an outside security company for Peach Bottom in 2007 after a videotape surfaced of sleeping guards in a "ready room" at the plant.

Ten guards from Florida-based Wackenhut Corp. were found to be taking "power naps" during their 12-hour shifts. The security guard who filmed his co-workers sleeping also lost his job when Exelon Nuclear terminated its contract with the company.

The guards shown to be inattentive were not responsible for patrolling the plant but were on duty in the ready room to respond immediately if a security threat was detected.

Exelon Nuclear spokeswoman Beth Archer said the company will pay the fine. Archer said Exelon's monitoring of plant security has improved since the company established an in-house security force.

Peach Bottom is one of 10 sites where Exelon produces energy from 17 nuclear reactors. Exelon also owns Three Mile Island, just south of Harrisburg on the Susquehanna River.

In 2006, reports of inattentiveness by a shift manager and security workers at TMI prompted Gov. Ed Rendell to order surprise, off-hour inspections by the Department of Environmental Protection at the state's five nuclear power plants. The NRC scheduled extra inspections at the Peach Bottom power station after this latest security lapse.