[6] The storage was not designed to house spent fuel permanently, but when plans for Yucca Mountain nuclear waste repository were terminated, OPPD stated that they are "prepared to safely store material on-site as long as necessary".

A fire caused electricity to shut off in the spent fuel pools resulting in 90 minutes without cooling[9] qualifying as a "red event", signifying a high-level threat to Fort Calhoun operations.

[16][17] The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Fort Calhoun was 1 in 76,923, according to a NRC study published in August 2010.

The risk assessment stated that at 1,010 feet (310 m), flooding would have "led to a 100 percent chance of a fuel damage if the emergency gasoline pumps didn't work.

[25] It was reported on June 17, 2011 that the plant was in "safe cold shutdown" mode for refueling and the anticipation of flooding,[26] and that four weeks' worth of additional fuel had been brought in to power backup generators, should they be needed.

[27] On June 7, 2011, an electrical component in a switch gear room caused a small fire with Halon extinguisher activation which forced a partial evacuation.

[31][32] On June 23 a helicopter contracted by OPPD to survey transmission lines made an unplanned landing 1.5 miles (2.4 km) south of the plant.

[33] The Federal Aviation Administration had declared a "temporary flight restriction," in a 2 nautical miles (3.7 km) radius, centered on the Fort Calhoun nuclear facility.

"[34] Officials noted that the June 6 FAA directive was actually a reminder to a standing order creating no flight zones over all U.S. nuclear power plants which had been in effect after the 2001 9/11 attacks.

[35] On June 26, at 1:30 a.m., an 8-foot (2.4 m) high, 2,000-foot (610 m) long water filled rubber "flood berm" that surrounded portions of the plant was punctured by a small earth mover ("Bobcat") and collapsed.

[39] The rupturing of the flood berm also resulted in approximately 100 US gallons (380 L; 83 imp gal) of petroleum being released into the river as many fuel containers were washed out.

[40] The rubber berm was a secondary measure not mandated by the NRC and was put in place by OPPD to provide additional room for work immediately outside the reactor buildings.

[45][46] Before restarting OPPD spent $180 million recommissioning the plant, and cleared a list of 450 corrective items issued by the NRC.

[50][51] Two weeks later on January 9, 2014, the plant had to stop producing power again after workers discovered a damaged sluice gate.

He discussed the report:[53] David Lochbaum, the director of the Nuclear Safety Project for the Union of Concerned Scientists, said the structural problems should have been caught much earlier, and that if the NRC conducted "more than just spot checks," it might have uncovered them in 2003.

On June 16, 2016 the Omaha Public Power District board voted unanimously to shut down the Fort Calhoun Plant.

"Once closed, a nuclear plant must undergo a decommissioning process to remove or decontaminate materials and equipment that have been exposed to radioactivity.

The Safstor method involves placing the facility into safe storage for 40 to 60 years, and proceeding with the decontamination after that time.