Arkansas Nuclear One (ANO) is a two-unit pressurized water nuclear power plant located on Lake Dardanelle outside Russellville, Arkansas. Owned by Entergy Arkansas and operated by Entergy Nuclear, it is the only nuclear power facility in Arkansas. Units Unit One Unit One has a generating capacity of 846 megawatts and came online on May 21, 1974. It is licensed to operate through May 20, 2034. Its nuclear reactor was supplied by Babcock & Wilcox. Unit Two Unit Two has a generating capacity of 930 megawatts and came online on September 1, 1978. It is licensed to operate through July 18, 2038. Its nuclear reactor was supplied by Combustion Engineering. Unit Two is the only one that uses a cooling tower; Unit One releases heat into Lake Dardanelle. Surrounding population The Nuclear Regulatory Commission 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 Arkansas Nuclear was 44,139, an increase of 17.2 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 U.S. population within was 308,219, an increase of 13.3 percent since 2000. Cities within 50 miles include Russellville (6 miles to city center). Seismic risk The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Arkansas Nuclear was 1 in 243,902, according to an NRC study published in August 2010. March 2013 incident On March 31, 2013, an industrial accident at the facility killed one person and injured eight other workers, including four seriously. The accident took place "in a non-radiation area, and there was no risk to public health and safety." According to Entergy, the old stator of Unit One's generator fell during an operation to replace it. The falling component ruptured a water pipe, causing water infiltration into the plant's switchgear, which knocked out power to all of Unit One and one train of Unit Two's electrical system, which was online at the time. The electrical failure caused an automatic shutdown of Unit Two. The plant's emergency generators started and restored power to the emergency systems of both units. Unit One was in