The outage rate at the nation’s fleet of 104 nuclear reactors has been higher in 2012, mainly because of problems at four reactors.
The graph shows the rate of outage over the year in gigawatts. (The largest reactors usually generate 1 gigawatt.) The horizontal axis, left to right, represent the year from January to December. The vertical axis measures outages across the country, from zero to 40 gigawatts. The dark blue line shows the average for 2007-2011. The shaded gray area shows the range over those five years. The light blue line tracks the rate for 2012.
Planned outages generally occur in the spring and fall when utilities face low electrical demand. Refueling operations, which require shutdown for about three weeks, are scheduled for these periods. Unplanned outages occur when there are difficulties at the plant. Currently four reactors have been in long-term shutdown. They are:
- Southern California Edison's San Onofre, Units 2 and 3, where a steam tube leak last January led to the discovery of excessive wear in the plant’s new steam generators. The station's 2,159 megawatts (2.15 GW) have been down all summer and may not reopen until well into 2013.
- Progress Energy’s Crystal River Unit 3 (860 MW) has been offline since September 2009 because of cracks created when the containment was breached in order to install a new generator. Duke Energy recently acquired Progress and has not yet decided whether to try to reopen the plan.
- The Omaha Public Power District’s Fort Calhoun reactor (478 MW) has been offline since April 2011 when it was flooded by a rise in the Missouri River. The Nuclear Regulatory Commission has refused to allow reopening because of additional issues. In August OPPD hired Exelon to manage the plant.
- Turkey Point Unit 3 in Miami (693 MW) underwent repairs through the spring and summer and only returned to service in October.
Nuclear energy still provides 20 percent of the nation’s electricity and is the most reliable source of base load power. But the fleet is aging and very little is being built to replace it.