Oconee Nuclear Station


The Oconee Nuclear Station is a nuclear power station located on Lake Keowee near Seneca, South Carolina, and has an energy output capacity of over 2,500 megawatts. It is the second nuclear power station in the United States to have its operating license extended for an additional twenty years by the Nuclear Regulatory Commission .
This plant has three Babcock & Wilcox pressurized water reactors, and is operated by Duke Energy.
Oconee was the first of three nuclear stations built by Duke Energy.
According to Duke Energy's web site, the station has generated more than 500 million megawatt-hours of electricity, and is "the first nuclear station in the United States to achieve this milestone."
In the summer of 2011 it became the first nuclear power station in the United States to have its sensors controlled digitally.
Oconee is unique as it is the only nuclear power plant in the United States that does not rely on emergency diesel generator sets for emergency power. Instead it relies on two hydroelectric units at the nearby Keowee hydroelectric station. In the event the Keowee units are both out of service emergency power can alternatively be provided by combustion turbines at the nearby Lee fossil generating station. Both sources use alternative cables to supply Oconee's emergency systems that are independent of the Oconee switchyard and transmission lines which are the normal source of power.

Surrounding population

The NRC defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of, concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about, concerned primarily with ingestion of food and liquid contaminated by radioactivity.
The 2010 U.S. population within of Oconee was 66,307, an increase of 11.5 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. This includes the main campus of Clemson University. The 2010 U.S. population within was 1,404,690, an increase of 14.8 percent since 2000. Cities within 50 miles include Greenville.

Seismic risk

The NRC's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Oconee was 1 in 23,256, according to an NRC study published in August 2010.

Flood risk

Duke Energy has noted that a rapid failure of the Jocassee dam would flood the plant and cause the loss of power and safety equipment, potentially damaging its three reactor cores within 8 to 9 hours. It could further lead to reactor containment failure within 59 to 68 hours, triggering a significant release of radioactivity into the environment. Duke informed the NRC about this flooding hazard as early as January 1996. Duke Energy estimated the probability of a random failure of Jocassee Dam is 1.3/year, while the NRC puts the estimate at 2.8/year.
Subsequent to Fukushima, improvements were made to the Oconee site such that flooding from the failure of Jocassee Dam would not result in reactor core damage. The NRC has expressed satisfaction as of June 2016 with the flood protection modifications which included new or enhanced flood walls and moving some power lines and equipment to less flood-prone locations.