Station Blackout: Issues and Regulations

The term "station blackout" (SBO) refers to the complete loss of alternating current (ac) electric power to the essential and nonessential switchgear buses in a nuclear power plant (NPP). GDC 17 requires that on‐site and off‐site electrical power be provided to facilitate the functioning of structures, systems, and components important to safety. GDC 18 requires that electric power systems important to safety be designed to permit appropriate periodic inspection and testing of key areas and features to assess their continuity and the condition of their components. There are two specific areas of SBO requirements: SBO coping duration and SBO coping capability. Pursuant to 10 CFR 50.65, the NPP operator should know the grid's condition before taking a risk‐significant piece of equipment out of service and should monitor the grid for as long as the equipment remains out of service.