OMAHA — Federal regulators have approved a small change in flood preparations for Fort Calhoun nuclear plant.

The Nuclear Regulatory Commission license change issued Wednesday should ensure that the plant will down soon enough to be protected in a flood.

NRC spokeswoman Lara Uselding said the change reflects an issue identified before the 2011 Missouri River flooding and will make Fort Calhoun's flood plan more conservative.

The nuclear plant owned by Omaha Public Power District will now shut down whenever the river rises to 1,004 feet above sea level. Previously, the plan didn't require shutdown until the water hit 1,009 feet above sea level.

In 2011, flood water reached 1,006 feet above sea level and surrounded the nuclear plant, which was already shut down for maintenance. Barriers protected the plant's core.