Browns Ferry Nuclear Plant

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The Browns Ferry Nuclear Plant is located on the Tennessee River near Decatur and Athens, Alabama, on the north side (right bank) of Wheeler Lake. The site has three General Electric boiling water reactor (BWR) nuclear generating units and is owned entirely by the Tennessee Valley Authority (TVA). With a generating capacity of nearly 3.8 gigawatts, it is the second most powerful nuclear plant in the United States, behind the Palo Verde Nuclear Generating Station in Arizona, and the most powerful generating station operated by TVA.

Browns Ferry Nuclear Plant
Browns Ferry Nuclear Power Plant (NRC image)
Browns Ferry Nuclear Power Plant (NRC image)
CountryUnited States
LocationAthens, Limestone County, Alabama
Coordinates34°42′14″N 87°7′7″W / 34.70389°N 87.11861°W / 34.70389; -87.11861Coordinates: 34°42′14″N 87°7′7″W / 34.70389°N 87.11861°W / 34.70389; -87.11861
Construction beganUnits 1–2: May 1, 1967
Unit 3: July 1, 1968
Commission dateUnit 1: August 1, 1974
Unit 2: March 1, 1975
Unit 3: March 1, 1977
Construction cost$3.259 billion (2007 USD)[1]
Owner(s)Tennessee Valley Authority
Operator(s)Tennessee Valley Authority
Nuclear power station
Reactor typeBWR
Reactor supplierGeneral Electric
Cooling towers7 × Mechanical Draft
(supplemental only)[a]
Cooling sourceWheeler Lake
Thermal capacity3 × 3,952 MWth
Power generation
Units operational1 × 1,256 MW
1 × 1,259 MW
1 × 1,260 MW
Make and modelBWR-4 (Mark 1)
Nameplate capacity3,775 MWe
Capacity factor96.04% (2017)
78.07% (lifetime)
Annual net output27,848 GWh (2017)
External links
WebsiteBrowns Ferry Nuclear Plant
CommonsRelated media on Commons


The nuclear power plant is named after a ferry that operated at the site until the middle of the 20th century. Browns Ferry was TVA's first nuclear power plant; its approval occurred on June 17, 1966 and construction began in September 1966.[2] In 1974, the time of its initial operation, it was the largest nuclear plant in the world. It was the first nuclear plant in the world to generate more than 1 gigawatt of power.[3] The lake provides main cooling, and 7 small fan towers assist during limitations on water temperature.[1][4] The 600 ft concrete chimney vents gases.[5][4]

In 2006, the Nuclear Regulatory Commission (NRC) renewed the licenses for all three reactors, extending their operation for an additional twenty years past their original 40-year licensing period.

TVA employs 1500 people at the plant, making it the largest employer in Limestone County, Alabama as of 1 March 2018.[6] A planned Toyota-Mazda factory north of the unincorporated town of Greenbrier will employ 4000 when completed.[7]

Power UpratesEdit

On August 16, 2017, the NRC approved TVA's request for a 14.3% uprate of each reactor's output. Each unit's gross electrical output was 1,155 MWe (1,101 MWe net), but after power uprates during refueling outages in Fall 2018 for Unit 1, Spring 2019 for Unit 2, and Spring 2018 for Unit 3, the gross electrical output for each unit was increased to 1,310 MWe (1,256 MWe net). The uprate for Unit 3 was completed in July 2018,[8] and in January 2019 for Unit 1.[9] The final uprate, for Unit 2, was completed in August 2019, completing the $475 million project.[10]

The electrical power increase of each unit was facilitated by the maximum operating thermal output of each reactor being increased from 3,458 MWth to 3,952 MWth.[11]

Unit 1Edit

Unit 1 under construction

Unit 1 is a 1,256 MWe net BWR/4 built by General Electric. Construction started on Unit 1 on September 12, 1966[2] and originally came online on December 20, 1973. Commercial operation began on August 1, 1974.[12] It was licensed to operate through December 20, 2013.[13] Unit 1 was shut down for a year after a fire in 1975 damaged the unit. The unit was subsequently repaired and operated from 1976 through March 3, 1985, when all three Browns Ferry units were shut down for operational and management issues.

Starting in 2002, TVA undertook an effort to restore Unit 1 to operational status, spending $1.8 billion USD to do so. The NRC approved the restart of Unit 1 on May 15, 2007 and the reactor was brought up to criticality on May 22.[14] During initial testing after restart, on May 24, 2007, a leaky hydraulic control pipe in the turbine hall burst, spilling about 600 US gallons (2,300 l; 500 imp gal) of non-radioactive fluid, and the newly restarted reactor was temporarily powered down. Reactor power-up and tests resumed on May 27 and the unit started supplying power to the electricity supply grid on June 2, 2007, reaching full power on June 8. The Browns Ferry restart was estimated to pay for itself in five years.[15]

On May 4, 2006, NRC issued a renewed license, adding twenty years to operate through December 20, 2033.[13]

Unit 1 generated 9,801 GWh of electricity in 2017, achieving a capacity factor of 101.62%.

Unit 1 fireEdit

Polyurethane foam used to fill a cable tray penetration at a power plant in Nova Scotia (subsequently removed and replaced with firestop mortar).

On March 22, 1975 a fire started when a worker using a candle to search for air leaks accidentally set a temporary cable seal on fire. At Browns Ferry, foamed plastic, covered on both sides with two coats of a flame retardant paint, was used as a firestop. The fire spread from the temporary seal into the foamed plastic, causing significant damage to the reactor control cabling in the station.[16]

An NRC bulletin explained the circumstances of the fire.

The fire started in the cable spreading room at a cable penetration through the wall between the cable spreading room and the reactor building for Unit 1. A slight differential pressure is maintained (by design) across this wall, with the higher pressure being on the cable spreading room side. The penetration seal originally present had been breached to install additional cables required by a design modification. Site personnel were resealing the penetration after cable installation and were checking the airflow through a temporary seal with a candle flame prior to installing the permanent sealing material. The temporary sealing material was highly combustible, and caught fire. Efforts were made by the workers to extinguish the fire at its origin, but they apparently did not recognize that the fire, under the influence of the draft through the penetration, was spreading on the reactor building side of the wall. The extent of the fire in the cable spreading room was limited to a few feet from the penetration; nonetheless, the presence of the fire on the other side of the wall from the point of ignition was not recognized until significant damage to cables related to the control of Units 1 and 2 had occurred.[17]

This later resulted in the Nuclear Regulatory Commission making significant additions to the standards for fire protection through the publication of 10CFR50.48 and Appendix R. According to the Nuclear Information and Resource Service, the newly restarted Unit 1 does not comply with these standards.[citation needed] Unit 3 was not affected by the accident. This event was pivotal not just for firestopping in the nuclear field, but also in commercial and industrial construction. While the nuclear field went to installations of silicone foam, a wider array of firestops became prevalent in non-nuclear construction.[citation needed]

Unit 2Edit

Unit 2 is a 1,259 MWe net BWR/4 built by General Electric that originally came online on August 2, 1974, and is licensed to operate through June 28, 2034. Unit 2 generated 8,396 GWh of electricity in 2017, achieving a capacity factor of 86.81%.

Unit 2 returned to service in 1991, after all three reactors were shut down in 1985.[18] During a drought in August 2007, Unit 2 was shut down for one day because water temperature in the Tennessee River rose too high for the water to be used for cooling and then discharged back into the river.[19]

Beginning in 2005 Unit 2 was loaded with BLEU (Blended Low Enriched Uranium) recovered by the DOE from weapons programs. This fuel contains quantities of U-236 and other contaminants because it was made from reprocessed fuel from weapons program reactors and therefore has slightly different characteristics when used in a reactor as compared to fresh uranium fuel. By making use of this fuel, which would otherwise have been disposed of as waste, the TVA is saving millions of dollars in fuel costs and accumulating a database of recycled uranium reactions in LWR use.[20]

Unit 3Edit

Unit 3 is a 1,260 MWe net BWR/4 built by General Electric that originally came online on August 18, 1976 with a capacity of 1,105 MWe net, and is licensed to operate through July 2, 2036. Unit 3 returned to service in 1995 after all three units were shut down in 1985 for maintenance and repairs.[18] Unit 3 generated 9,651 GWh in 2017, achieving a capacity factor of 99.70%. The power update of 155 MWe was completed in July 2018.

Additional incidentsEdit

March 19, 1985Edit

TVA decided to shut the entire plant down and keep it shut down indefinitely in order to focus on making improvements to all three units in order to bring it back into regulatory compliance following extremely negative assessments from the NRC.[21] Unit 2 finally resumed operation on May 24, 1991, with Unit 3 following it on November 1, 1995, although Unit 1 did not resume operation until June 2, 2007.

May 10, 1986Edit

Cooling tower #4 (which was 90 feet (27 m) wide, 300 feet (91 m) long, and four stories tall) was destroyed in a fire caused by sparks from the electrical cooling fans in the tower hitting the abnormally dry redwood slats within the tower on May 10, 1986. During normal operation, water was kept flowing near-continuously over the redwood slats within the tower, but after close to two months of inactivity, the slats were very dry and extremely flammable.[22][23] $5 million of damage was done.[24]

May 23, 1996Edit

Cooling tower #3 (which was in the process of being refurbished at the time) was heavily damaged in a fire on May 23, 1996, with about 80% of the tower destroyed.[24]

April 27, 2011Edit

Towers crumpled by the tornado.

At 5:01 PM on April 27, 2011, all three reactors scrammed due to loss of external power caused by a tornado in the vicinity of the plant. Control rod insertion and cooling procedures operated as designed with no physical damage or release of radiation. Diesel backup generators provided power after a brief period of outage. An NRC Unusual Event, the lowest level of emergency classification, was declared due to loss of power exceeding 15 minutes. Additionally, a small oil leak was found on one generator. Due to widespread transmission grid damage from the storms, Browns Ferry was unable to produce power for the grid and significant blackouts occurred throughout the Southeastern United States.[25][26]

January 2015Edit

A drain line leaked 100-200 gallons of water containing tritium levels above acceptable EPA drinking water standards. The leak was fixed within three hours of when it was discovered and was largely contained within the plant area.[27]

May 2015Edit

The Nuclear Regulatory Commission found that 5 contract workers failed to conduct roving fire watch patrols as required by NRC. As a result, Tennessee Valley Authority was fined $140,000 for failing to maintain adequate fire watches in 2015 at Browns Ferry.[28]

Surrounding populationEdit

The 2010 U.S. population within 10 miles (16 km) of Browns Ferry was 39,930, an increase of 12.3 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 977,942, an increase of 11.0 percent since 2000. Cities within 50 miles include Huntsville (28 miles to city center).[29]

Seismic riskEdit

According to an NRC study using geological data from 1989 to 2008 which was published in August 2010, the estimated risk of an earthquake intense enough to cause core damage to reactor one was 1 in 270,270, and for reactors two and three, the risk was 1 in 185,185.[30][31]

See alsoEdit


  1. ^ The plant is operated in an open-cycle mode of operation with up to seven additional mechanical draft "helper" cooling towers that are used as necessary in order to comply with regulations on discharge water temperature limits. One or more of the plant's units can also be derated (operated at a reduced power level) in order to maintain discharge water temperature within permitted limits, although this is only done as a last resort as it reduces revenues. The plant was designed to also be able to operate in a fully closed-cycle mode, but due to difficulties operating in this mode, it has not been used since at least 1991.


  1. ^ a b "EIA - State Nuclear Profiles". Retrieved 3 October 2017.
  2. ^ a b "TVA timeline by year" (PDF). Tennessee Valley Authority. Archived from the original (PDF) on 4 August 2010. Retrieved 5 August 2009.
  3. ^ "Browns Ferry Nuclear Plant". Tennessee Valley Authority (TVA). Retrieved 2008-11-18.
  4. ^ a b "BROWNS FERRY NUCLEAR PLANT UNIT 1 SEISMIC IPEEE REPORT, TVANBFN-01 -R-005" (PDF). NRC. October 7, 2004. The residual heat removal service water intake structure is a single structure serving all three units. The reinforced concrete chimney stands 600 feet high and varies in diameter from 62 feet at the base to 6 feet at the top
  5. ^ Jonsson, Asgeir; Smith, John W. (1970). "Design of Browns Ferry Chimney". Journal of the Power Division. pp. 437–447.
  6. ^ Major Employers, Limestone County Economic Development Association, retrieved 2018-03-01
  7. ^ It's official: Toyota-Mazda announce Alabama factory,, 11 Jan 2018
  8. ^ Flessner, Dave (2018-07-24). "TVA boosts power output at newest Browns Ferry reactor". Chattanooga Times Free Press. Chattanooga, Tennessee. Retrieved 2018-11-16.
  9. ^ "Browns Ferry 2 taken offline for power uprate". Nuclear Engineering International Magazine. March 7, 2019. Retrieved 2019-08-30.
  10. ^ "TVA completes nearly $500M upgrade at Browns Ferry nuclear plant". Power Engineering. August 8, 2019. Archived from the original on 2019-08-26. Retrieved 2019-08-26.
  11. ^ "NRC Approves Extended Power Uprate for Browns Ferry Nuclear Plant" (PDF). Nuclear Regulatory Commission. August 16, 2017. Retrieved October 19, 2017.
  12. ^ "Browns Ferry No. 2 N-Unit Test Approved". The Tennessean. Nashville, Tennessee. Associated Press. August 9, 1974. p. 6. Retrieved 2020-08-23 – via
  13. ^ a b "Browns Ferry Nuclear Plant, Unit 1". United States Nuclear Regulatory Commission. 2017. Archived from the original on May 2, 2017. Retrieved August 21, 2017.
  14. ^ "TVA Restarts Browns Ferry Unit 1". Tennessee Valley Authority. May 22, 2007. Archived from the original on June 15, 2007. Retrieved August 21, 2017.
  15. ^ Blair, Elliot (2007-07-09). "New Reactor Costs Daunt U.S. Utilities as TVA Restarts Old Unit". Bloomberg. Retrieved 2011-03-28.
  16. ^ Fisher, Brad (April 4, 1979). "Nuclear risk-benefit ratio needs a much closer look". The Tuscaloosa News. Retrieved August 19, 2020 – via Google News. The fire burned for seven hours, damaging scores of cables that provide the control room staff their eyes and ears to the two 1.1 million kilowatt reactors. Core cooling systems, pumps, dials and switches were knocked out by the fire. But plant workers found a way to press the auxiliary pumps into service, which kept the reactor cooled and allowed for a safe shutdown of the reactors after about 15 hours.
  17. ^ "IE Bulletin No. - 75-04A: Cable Fire at Browns Ferry Nuclear Plant". United States Nuclear Regulatory Commission. April 3, 1975.
  18. ^ a b "Browns Ferry Nuclear Power Plant, Alabama, USA". Verdict Media Limited. 2007. Retrieved 2018-11-16. All three units of the Browns Ferry plant were actually shut down in 1985, but they retained their NRC operating licences. Unit 2 came back on line in 1991, and Unit 3 in 1995 at a cost of US $1.8bn, which was also the estimated cost of restarting Unit 1.
  19. ^ Mitch Weiss, Drought Could Force Nuclear Plants to Shut Down, Associated Press, January 23, 2008, retrieved from WRAL-TV website, April 7, 2009
  20. ^ TVA press release Archived September 25, 2006, at the Wayback Machine
  21. ^ United States General Accounting Office (13 August 1987). Nuclear Regulation: Efforts To Ensure Nuclear Power Plant Safety Can Be Strengthened (PDF) (Report). United States General Accounting Office. p. 40. OCLC 878522216. RCED-87-141. Retrieved 20 May 2018.
  22. ^ Mahaffey, James (2014-02-04). Atomic Accidents: A History of Nuclear Meltdowns and Disasters: From the Ozark Mountains to Fukushima (1st ed.). Pegasus Books. ISBN 9781480447745.
  23. ^ "Fire Destroys Cooling Tower at Nuclear Plant". AP News. 11 May 1986. Retrieved 21 May 2018.
  24. ^ a b "Blaze Heavily Damages Unused Cooling Tower At Nuclear Plant". AP News. 23 May 1996. Retrieved 21 May 2018.
  25. ^ NRC: Event Notification Report for April 28, 2011
  26. ^ TVA: Power Restoration Updates Archived May 2, 2011, at the Wayback Machine
  27. ^ "Tritium Leak".
  28. ^ "TVA fined $140,000 for fire violations at Browns Ferry Nuclear Plant; from google (brown ferry nuclear plant drought) result 7".
  29. ^ Bill Dedman, Nuclear neighbors: Population rises near US reactors, NBC News, April 14, 2011 Accessed May 1, 2011.
  30. ^ Bill Dedman, "What are the odds? US nuke plants ranked by quake risk," NBC News, March 17, 2011 Accessed April 19, 2011.

External linksEdit

  Media related to Browns Ferry Nuclear Power Plant at Wikimedia Commons