A Nebraska environmental group is questioning the track record of the company hired to run the Fort Calhoun nuclear power plant because of concerns federal regulators raised.

The Clean Nebraska group said Monday that questions the Nuclear Regulatory Commission is raising about some of the calculations Exelon made for its other nuclear plants are troubling.

The NRC says it is looking into whether Chicago-based Exelon intentionally understated the cost of decommissioning many of its nuclear plants.

Exelon spokesman David Tillman says the company denies intentionally providing incorrect data. Tillman says the calculations are complicated and Exelon looks forward to meeting with the NRC.

The Omaha Public Power District hired Exelon last year because of its experience and safe track record. Fort Calhoun has been idle since 2011.