Frequently Asked Questions About the Loss of the Electric Power Grid on August 14, 2003

On this page:

• What Happened?
• What Nuclear Power Plants Shut Down?
• Why Did Nuclear Power Plants Shut Down?
• When Can The Plants Restart?
• What Has The NRC Done?

Index to All Frequently Asked Questions Pages

What Happened?

A power distribution grid disturbance of unknown origin occurred in the Northeastern and Midwestern portions of the United States and in parts of Canada just after 4:00 p.m. on Thursday, August 14, causing nine U.S. nuclear power plants and 12 non-nuclear U.S. power plants to shut down within a three-minute period. The grid disturbance resulted in widespread electrical power blackouts in these areas.

What Nuclear Power Plants Shut Down?

Nuclear plants that experienced automatic shutdowns were:
New York - Indian Point Units 2 and 3; Nine Mile Point Units 1 and 2; FitzPatrick; and Ginna.
New Jersey - Oyster Creek
Ohio - Perry (Davis Besse was already shut down)
Michigan - Fermi

As of 2:00 p.m. on Friday, August 15, offsite power had been restored to FitzPatrick, Ginna, Indian Point 2 and 3, and Nine Mile Point 1 and 2. Oyster Creek maintained offsite power during the grid instability. The remaining plants continued to have adequate onsite backup power to maintain the plants in a safe shutdown condition.

Why Did Nuclear Power Plants Shut Down?

Instability of unknown origin on the electrical power distribution grid caused protective circuits at the plants to automatically shut down each reactor to protect equipment. All affected nuclear power plants functioned as designed and are safely shut down. Onsite power sources such as backup diesel generators provided power to operate essential safety systems. While we do not know the root cause of the incident, we have no information that would lead us to believe that an event at a nuclear power plant was the cause.

When Can The Plants Restart?

As of 11:00 a.m. August 15 2003, no schedules had been establishedfor restart of the affected nuclear power plants. Plant owners willmake those decisions based on discussions with their load dispatchers.

What Has The NRC Done?

The NRC activated incident response centers in its headquarters and regional offices. Additionally, NRC inspectors were sent to monitor licensee activities at each of the nine plants. NRC monitoring of plant activities associated with the grid disturbance continues. Plant safety was and continues to be maintained.