Since then, the plant has accounted for about one-third of OPPD’s total electricity generation. At its recent peak, Calhoun was responsible for 700 high-paying jobs.

But a different force has darkened the doors of existing nuclear plants in recent years.

The glut of low-priced natural gas that has been a major driver in forcing other, far larger nuclear plants into premature shutdowns has also doomed Fort Calhoun. In the last seven months alone, four other nuke plants have been dispatched into early twilight, rendered too expensive to operate because of cheap and plentiful electricity from other sources.

Still, Fort Calhoun differs from these other recent cases: The local plant has been on financial life support since returning from a disastrous spell in which it was shut down for more than 30 months between April 2011 and December 2013.

The utility spent heavily to recover from a historic Missouri River flood, a costly electrical fire and a subsequent laundry list of hundreds of performance-related deficiencies exposed by federal regulators.

The facility recovered, but at a steep cost: The fire alone cost the utility almost $40 million. In all, OPPD spent about $300 million to recover from the prolonged outage.