Nuclear plant outages were very rare during this past summer and unplanned outages hit an all-time low in 2014, according to data released Sept. 28 by the Energy Information Administration (EIA).
It’s the latest finding on the increased reliability of the U.S. nuclear fleet, which is often touted by the Nuclear Energy Institute (NEI), which is the U.S. industry trade group.
Outages at U.S. nuclear power plants were extremely low this summer (June through August), averaging 2.9 GW, or less than 3% of total U.S. nuclear capacity. During four days in August, outages dropped to just 0.1 GW out of a total U.S. nuclear capacity of 98.7 GW, the lowest value recorded since the U.S. Nuclear Regulatory Commission (NRC) began collecting data in 2007.
Nuclear power plants provide baseload electricity generation and do not change output in response to daily or hourly fluctuations in electricity demand, as do power plants running on other fuels, such as natural gas. In June, nuclear power accounted for nearly 20% of total U.S. electricity generation.
Although nuclear plant outages are typically low during the summer and winter months, when electricity demand is relatively high, outages this year have been much lower than normal
The same analysis from EIA also noted that unplanned automatic or manual reactor shutdowns also reached a record low of 59 shutdowns in 2014. By comparison, more than 100 unplanned shutdowns were reported in 2003.
The EIA also reports that the duration of regularly-scheduled refueling and maintenance outages continues to shrink.
Nuclear reactors typically refuel every 18 to 24 months. Although a reactor can be fueled in as little as 10 days, refueling-related outages often last longer, as operators schedule other noncritical maintenance work at the same time to minimize downtime.
The average duration of nuclear power plant refueling outages has been steadily declining. In the early 1990s, refueling-related outages lasted about three months. More recently, these outages lasted six weeks.
Nancy Slater-Thompson was the chief author of the EIA analysis.