River Ice Forces Shutdown at Fort Calhoun Nuclear Plant

Nebraska's Fort Calhoun nuclear plant – recently returned to service after nearly three years offline to address regulatory concerns – was forced to shut down Thursday because of freezing conditions on the adjacent Missouri River.

Fort Calhoun nuclear plant. Source: OPPDA plant worker on rounds found that a block of ice had formed on an intake structure sluice gate. According to a report filed with the Nuclear Regulatory Commission, the gate could not be closed. As a result, technical specifications required that the raw water pumps be declared inoperable, and the plant was manually shut down. The other five sluice gates were not affected.

Flooding was not anticipated, but all six gates must be able to close in case flood conditions develop, according to a release from the Omaha Public Power District. The plant was offline by 9 a.m. and the shutdown was uncomplicated.

Also on Thursday, an inspection of fittings connected to a containment penetration revealed a small leak. According to another NRC report, "a minor leak from a pipe fitting was discovered on the primary sampling piping connected to penetration M-45. There was previously identified minor leakage from a fitting on this same penetration outside of containment in the auxiliary building. The containment isolation valves are currently tagged closed."