U.S. nuclear power plants showed marked improvements in performance this summer and saw outages fall to the lowest level ever recorded in early August since federal regulators began collecting such data in 2007, according to a new report by the U.S. Energy Information Administration.
The news comes as Entergy Arkansas recently took Arkansas Nuclear One Unit 2 offline for a planned refueling outage on Sept. 20. The outage, utility officials said, will bring more than 1,100 additional workers and robust economic benefits to the River Valley region in Russellville while the unit undergoes refueling and maintenance after 465 straight days of operation.
According to the EIA, Between June and August, outages at the nation’s nuclear fleet averaged 2.9 gigawatts (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).
The NRC said 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 decrease in nuclear power plant outages, both planned and unplanned, may be attributable to several factors, including:
Shorter refueling-related outages
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.
Uprates to nuclear reactors, in which a power plant increases its maximum generating capacity, generally involve physically modifying the power plant and require the plant to be offline. Large or extended uprates may even be implemented over the course of two refueling outages.
In early 2013, five reactors completed extended power uprates totaling more than 600 megawatts (MW), which required lengthy outages. In contrast, uprates currently under review and pending approval by the NRC total just 61 MW, and the NRC expects to receive additional requests for a total of only 580 MW between 2015 and 2019, out of a total capacity of 98.7 GW.
Improved operating performance
U.S. nuclear power plant performance and reliability have consistently improved over the past 10 years. In 2014, the nuclear fleet operated at an average annual capacity factor—the measure of the capability of a power plant to remain online and generate electricity—of 91.7%. The nuclear fleet’s average estimated monthly capacity factor for August 2015 was 98.4%, compared with 96.4% for August 2014.
According to the Nuclear Energy Institute, 95 of 99 operating reactors achieved a capacity factor of 90% or higher during August, and 48 of the nation’s 99 operating nuclear reactors achieved a capacity factor of 100% or above—reported capacity factors slightly above 100% are possible because they are based on net summer capacity, which can be lower than actual maximum generation capacity. Unplanned automatic or manual reactor shutdowns also reached a record low of 59 shutdowns in 2014.
The EIA’s report also comes on the heels of a report on Monday that the NRC is streamlining the agency’s management later this year in an effort to cut costs and become more efficient.
“Our agency faces the challenge of reducing our size, becoming more efficient and delivering more value for the money,” said NRC Chairman Stephen G. Burns. “The steps announced (Monday) will put in place a management structure well suited to ensuring we accomplish our mission of protecting people and the environment even as we reduce our size and budget.”
ANO UNIT 2 REFUELING BRINGS $63 MILLION ECONOMIC BOOST TO RIVER VALLEY
In Arkansas, Russellville is home to two nuclear reactors owned and operated by Entergy Arkansas with a total general capacity of 1823 megawatts. Arkansas Nuclear One (ANO) Unit 1 began commercial operations December 19, 1974, followed less than six years later by Unit 2, which began commercial operations March 26, 1980.
Together, the units have enough capacity to supply more than 60% of the total energy demand of Entergy’s commercial and residential customers in Arkansas. After removing ANO Unit 2 offline last Sunday, Entergy Arkansas said it is spending $62.7 million to complete the refueling and other important maintenance projects for the nuclear reactor.
“Arkansas Nuclear One exists to safely and efficiently operate a world-class nuclear facility that creates sustainable value for our four stakeholders: our community, our employees, our shareholders and our customers. It is a privilege to be part of a team of dedicated nuclear professionals who met that vision during our last refueling outage and the past 465 days of safe and reliable operation,” said Jeremy Browning, ANO site vice president. “I am confident the team assembled for this refueling and maintenance outage will deliver a safe and efficient outage resulting in the same or better performance for the next cycle.”
Browning said work will be completed by nearly 1,000 ANO full-time employees and supported by Entergy employees from its other nuclear plants and contract workers including pipefitters, millwrights, ironworkers, carpenters, boilermakers, electricians, laborers, valve technicians, engineers, operating engineers and radiation protection technicians.
The influx of more than 1,100 outside workers and their associated spending will provide an economic boost to local communities, Entergy Arkansas officials said.