Arkansas Nuclear One

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Arkansas Nuclear One
Arkansas Nuclear One, February 2010.
CountryUnited States
LocationClark Township, Pope County, near Russellville, Arkansas
Coordinates35°18′37″N 93°13′53″W / 35.31028°N 93.23139°W / 35.31028; -93.23139Coordinates: 35°18′37″N 93°13′53″W / 35.31028°N 93.23139°W / 35.31028; -93.23139
Construction beganUnit 1: October 1, 1968
Unit 2: December 6, 1968
Commission dateUnit 1: December 19, 1974
Unit 2: March 26, 1980
Construction cost$2.522 billion (2007 USD)[1]
Owner(s)Entergy Arkansas
Operator(s)Entergy Nuclear
Nuclear power station
Reactor typePWR
Reactor supplierUnit 1: Babcock & Wilcox
Unit 2: Combustion Engineering
Cooling sourceLake Dardanelle
Cooling towers1 × Natural Draft
(Unit 2 only)
Power generation
Units operational1 × 836 MW
1 × 993 MW
Make and modelUnit 1: B&W LLP (DRYAMB)
Unit 2: CE 2-loop (DRYAMB)
Thermal capacity1 × 2568 MWth
1 × 3026 MWth
Nameplate capacity1829 MW
Capacity factor79.36% (2017)
80.75% (lifetime)
Annual net output12,715 GWh (2017)

Arkansas Nuclear One (ANO) is a two-unit pressurized water reactor nuclear power plant located on Lake Dardanelle just outside Russellville, Arkansas. It is the only nuclear power plant in Arkansas.

It is owned by Entergy Arkansas and operated by Entergy Nuclear.


Unit One[edit]

Unit One has a generating capacity of 846 MW of electricity, and came online on May 21, 1974. It is licensed to operate through May 20, 2034.[2] Its nuclear reactor was supplied by Babcock & Wilcox.

Unit Two[edit]

Unit Two has a generating capacity of 930 MW of electricity, and came online on September 1, 1978. It is licensed to operate through July 18, 2038.[3] 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[edit]

The Nuclear Regulatory Commission defines two emergency planning zones around nuclear power plants: a plume exposure pathway zone with a radius of 10 miles (16 km), concerned primarily with exposure to, and inhalation of, airborne radioactive contamination, and an ingestion pathway zone of about 50 miles (80 km), concerned primarily with ingestion of food and liquid contaminated by radioactivity.[4]

The 2010 U.S. population within 10 miles (16 km) 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 The 2010 U.S. population within 50 miles (80 km) was 308,219, an increase of 13.3 percent since 2000. Cities within 50 miles include Russellville (6 miles to city center).[5]

Seismic risk[edit]

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.[6][7]

March 2013 incident[edit]

Arkansas Nuclear One cooling tower.jpg

On March 31, 2013, an industrial accident at the facility killed one person and injured eight other workers, including four seriously.[8] 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 a refueling outage.[9] Emergency diesel generators, water pumps and feed water were functioning following a loss of all off-site power on Unit One, according to the NRC event notification.[10] The plant was placed under an "unusual event classification", which is the lowest of four emergency classification levels for abnormal events designated by the federal Nuclear Regulatory Commission, which regulates American civil nuclear installations. One plant worker died, and ten other injuries required offsite medical treatment.[11] The company released an official statement of condolence.[12] Entergy announced that they would immediately commence repairs to Unit Two and hope to have the unit back online within several weeks. Entergy also acknowledged that Unit One would be offline for an extended time while the company surveyed the damage and established a timeline for repairs.[13]

The cost of the repairs was estimated at $95–120M, not counting additional costs to replace lost electricity from the reactors being down for four months. Both units were repaired, and started up on August 7, 2013 capable of returning to full power.[14] During the recovery from the incident a specialist engineering company named Lowther-Rolton [15] assisted with the recovery of the existing Stator and performed a "Technical Audit" of the engineering for lifting and installation of the new Stator to ensure safety of operations. Lowther-Rolton were the original developers of the Technical Audit system for load movement operations during the 1980s.

December 2013 incident[edit]

On December 9, 2013, Unit Two was taken offline due to a transformer fire in the site switchyard.[16] The fire was contained without injuries or threats to safety.[17]


  1. ^ "EIA - State Nuclear Profiles". Retrieved 3 October 2017.
  2. ^
  3. ^
  4. ^
  5. ^ Bill Dedman, Nuclear neighbors: Population rises near US reactors,, April 14, 2011 Accessed May 1, 2011.
  6. ^ Bill Dedman, "What are the odds? US nuke plants ranked by quake risk,", March 17, 2011 Accessed April 19, 2011.
  7. ^
  8. ^ "U.S. NRC Event Notification Report for April 1, 2013 (Event Number: 48869)". U.S. Nuclear Regulatory Commission. Retrieved 1 April 2013.
  9. ^ "One dead, three injured in Arkansas nuclear plant accident". NBC News. Retrieved 31 March 2013.
  10. ^ "U.S. NRC Event Notification Report for April 1, 2013 (Event Number: 48869)". U.S. Nuclear Regulatory Commission. Retrieved 1 April 2013.
  11. ^ ""Root Cause Evaluation Report, Unit 1 Main Turbine Generator," Entergy Operations, Arkansas Nuclear One" (PDF).
  12. ^
  13. ^
  14. ^
  15. ^
  16. ^ Power News
  17. ^ Arkansas Matters News

See also[edit]

External links[edit]