On October 6, 2010, the NRC issued a Notice of Violation to Omaha Public Power District for a violation of Technical Specification 5.8.1.a, "Procedures," at Fort Calhoun Station. This violation, which is associated with a Yellow Significance Determination Process finding, involved the licensee's failure to develop an adequate procedure for protecting vital facilities and equipment from external flooding events to the level described in the Updated Final Safety Analysis Report. Specifically, the inspectors identified that the licensee's strategy of using sandbags stacked on top of floodgates would not be effective in protecting the auxiliary building, intake structure, and turbine building basement because the tops of the floodgates were too small to support the necessary number of sandbags. This could have resulted in flooding impacting multiple, redundant trains of equipment required for safe shutdown of the plant.