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Watts Bar Nuclear Plant

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The Watts Bar Nuclear Plant is a Tennessee Valley Authority (TVA) nuclear reactor pair used for electric power generation. It is located on a 1,770-acre (7.2 km²) site in Rhea County, Tennessee, near Spring City, between Chattanooga and Knoxville. Watts Bar supplies enough electricity for about 1.2 million households in the Tennessee Valley.

Watts Bar Nuclear Plant
Watts Bar Nuclear Power Plant Units 1 & 2 cooling towers and containment buildings.
Map
CountryUnited States
LocationRhea County, near Spring City, Tennessee
Coordinates35°36′10″N 84°47′22″W / 35.60278°N 84.78944°W / 35.60278; -84.78944
StatusOperational
Construction beganUnit 1: July 20, 1973
Unit 2: September 1, 1973[a]
Commission dateUnit 1: May 27, 1996
Unit 2: October 19, 2016[a]
Construction costMore than $12 billion
OwnerTennessee Valley Authority
OperatorTennessee Valley Authority
Nuclear power station
Reactor typePWR
Reactor supplierWestinghouse
Cooling towers2 × Natural Draft
Cooling sourceTennessee River
Thermal capacity1 × 3459 MWth
1 × 3411 MWth
Power generation
Units operational1 × 1167 MW
1 × 1165 MW
Make and modelWH 4-loop (ICECND)
Nameplate capacity2332 MW
Capacity factor68.10% (2017)
73.45% (lifetime)
Annual net output16,808 GWh (2022)
External links
Websitewww.tva.gov/Energy/Our-Power-System/Nuclear/Watts-Bar-Nuclear-Plant
CommonsRelated media on Commons
[edit on Wikidata]

The plant, construction of which began in 1973, has two Westinghouse pressurized water reactor units: Unit 1, completed in 1996, and Unit 2, completed in 2015. Unit 1 has a winter net dependable generating capacity of 1,167 megawatts. Unit 2 has a capacity of 1,165 megawatts. Unit 2 was the first of three new power reactors to enter service in the 21st century in the United States, followed by Vogtle Electric Generating Plant Units 3 and 4.

Unit 1

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Construction on Unit 1 began on 23 January 1973 and suffered from many delays. After construction was halted on both units in 1985, construction resumed on Unit 1 in 1992.[1] Criticality was first achieved on 1 January 1996, and commercial operation began on May 5, 1996.[2]

In the early 2000s, the four original steam generator units were replaced with units made from Inconel 690 which is more resistant to stress corrosion cracking.[3]

Unit 2

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Unit 2 construction started in 1972.[4] Unit 2 was 60% complete when construction on both units was stopped in 1985 due in part to a projected decrease in power demand.[4][5] In 2007, the Tennessee Valley Authority (TVA) Board approved completion of Unit 2 on August 1, and construction resumed on October 15.[6] The project was expected to cost $2.5 billion and employ around 2,300 contractor workers. Once finished, it was expected to employ 250 people in permanent jobs.[7] The final cost of the plant is estimated at $6.1 billion.[4]

A year after the 2011 Tōhoku earthquake and tsunami and subsequent Fukushima Daiichi nuclear disaster, the Nuclear Regulatory Commission (NRC) issued 9 orders to improve safety at domestic plants. Two changes applied to Watts Bar Unit 2 and required design modifications: "Mitigation Strategies Order"[8] and "Spent Fuel Pool Instrumentation Order".[9] In February 2012, TVA said the design modifications to Watts Bar 2 were partially responsible for the project running over budget and behind schedule.[5] The second unit costs a total of $4.7 billion bringing the total costs of the two unit plant to more than $12 billion.[10] It will likely be the last Generation II reactor to be completed in the US.[11]

TVA declared construction substantially complete in August 2015 and requested that NRC staff proceed with the final licensing review; on October 22, the NRC approved a 40-year operating license for Unit 2, marking the formal end of construction and allowing for the installation of nuclear fuel and subsequent testing.[12] On December 15, 2015, TVA announced that the reactor was fully loaded with fuel and ready for criticality and power ascension tests. In March 2016, the NRC described the project as a "chilled work environment," where employees are reluctant to raise safety concerns for fear of retribution.[4]

On May 23, 2016, initial criticality was achieved.[13] Commercial operation began in October 2016.[14] On October 19, 2016 the Watts Bar 2 was the first United States reactor to enter commercial operation since 1996.[15] Due to failures in its condenser, TVA took it offline on March 23, 2017. The condenser, which was installed during the original construction phase of the plant in the 1970s, suffered a structural failure in one of its sections. On August 1, 2017, the unit was restarted after four months of repairs to the condenser.[4]

In 2022, the four original steam generator units installed in the 1970s on unit 2 were replaced with units made from Inconel 690 which is more resistant to stress corrosion cracking and expected to last the life of the plant. Replacing the units involved cutting two large holes in the containment building. Because of radioactive contamination the old units will be kept until the plant is decommissioned.[3]

Electricity Production

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Generation (MWh) of Watts Bar Nuclear Plant[16]
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual (Total)
2001 865,401 785,394 867,441 831,506 854,829 781,099 546,540 832,025 752,854 861,068 832,257 816,161 9,626,575
2002 867,654 666,737 247,153 828,559 668,949 812,577 786,082 831,704 811,209 854,034 840,231 863,464 9,078,353
2003 874,381 788,422 682,375 830,918 850,445 815,140 830,671 771,811 145,510 251,039 839,063 869,036 8,548,811
2004 790,787 812,896 861,019 829,429 844,969 809,214 831,329 830,935 708,344 846,240 828,868 862,873 9,856,903
2005 856,865 574,589 -12,464 787,969 850,040 806,093 827,508 822,971 760,234 845,165 827,117 857,868 8,803,955
2006 863,241 712,653 840,779 819,625 806,229 104,495 808,856 696,280 255,819 -6,120 -12,838 789,079 6,678,098
2007 847,063 794,789 842,491 842,160 860,541 817,964 842,218 822,564 813,716 852,528 841,477 872,175 10,049,686
2008 873,261 261,900 120,189 837,789 581,768 790,206 837,210 563,329 666,098 860,272 844,163 876,124 8,112,309
2009 878,273 791,352 831,643 840,996 857,449 815,615 841,810 838,200 534,880 272,182 832,706 872,359 9,207,465
2010 831,615 793,007 872,123 838,259 684,320 813,889 837,006 799,849 817,744 861,066 715,384 874,195 9,738,457
2011 875,658 786,916 791,302 57,454 116,536 798,773 833,360 824,327 819,858 629,340 836,448 861,012 8,230,984
2012 867,879 813,000 860,501 829,765 845,534 811,824 830,376 756,716 228,900 7,118 834,875 829,983 8,516,471
2013 866,265 782,801 864,022 827,505 845,863 744,031 833,711 837,231 813,145 853,805 840,348 859,076 9,967,803
2014 872,923 785,077 633,303 -12,074 738,213 810,194 754,183 830,449 809,351 848,741 838,751 868,504 8,777,615
2015 870,146 566,898 783,904 822,440 843,297 794,445 802,791 822,161 488,794 186,565 608,004 859,705 8,449,150
2016 863,426 800,168 706,793 800,663 818,177 762,692 1,034,064 906,079 792,838 1,422,247 1,664,235 1,764,096 12,335,478
2017 1,758,293 1,589,981 1,027,929 -22,258 569,823 773,659 825,538 1,512,310 1,677,002 1,626,640 847,376 1,389,910 13,576,203
2018 1,782,004 1,592,296 1,771,056 1,611,462 1,684,194 1,393,973 1,657,810 1,512,727 1,186,680 849,587 1,657,365 1,773,479 18,472,633
2019 1,776,869 1,433,694 1,762,683 1,172,709 1,138,695 1,649,612 1,683,870 1,686,646 786,465 1,089,909 1,711,324 1,763,310 17,655,786
2020 1,763,054 1,593,092 1,675,291 1,685,834 419,862 1,426,193 1,654,860 1,662,790 1,551,432 1,399,109 1,077,497 1,679,992 17,589,006
2021 1,685,672 1,520,935 1,599,308 1,592,636 1,621,629 1,541,734 1,584,771 1,582,295 1,044,650 1,527,420 812,929 1,561,616 17,675,595
2022 1,732,923 1,555,921 825,225 833,189 840,043 797,974 1,630,675 1,693,139 1,663,035 1,719,271 1,744,557 1,772,149 16,808,101
2023 1,755,010 1,592,494 1,754,083

Tritium production

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The NRC operating license for Watts Bar was modified in September 2002 to allow irradiation of tritium-producing burnable absorber rods at Watts Bar to produce tritium for the U.S. Department of Energy's (DOE's) National Nuclear Security Administration in order to maintain the viability of America's nuclear weapons. Tritium, the fusion fuel in nuclear weapons, has a half-life of 12.3 years, which means it decays at 5.5% per year and must be renewed. The Watts Bar license amendment permits TVA to irradiate up to approximately 2,000 tritium-producing rods in the Watts Bar reactor.[17]

TVA began irradiating tritium-producing rods at Unit 1 in the fall of 2003. TVA removed these rods from the reactor in the spring of 2005. DOE successfully shipped them to its tritium extraction facility at Savannah River Site in South Carolina. DOE reimburses TVA for the cost of providing the irradiation services and also pays TVA a fee for each tritium-producing rod that is irradiated. During the times the reactor does this, it must be fuelled with "unobligated" uranium, (uranium that is not legally or contractually restricted to peaceful use only, as most commercial reactor uranium is). Technology and equipment as well as the fuel used to produce it must be of U.S. origin.[17]

Surrounding population

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Watts Bar's cooling towers, with the Tennessee River in the foreground

The NRC 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.[18]

The 2010 U.S. population within 10 miles (16 km) of Watts Bar was 18,452, an increase of 4.1 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. The 2010 U.S. population within 50 miles (80 km) was 1,186,648, an increase of 12.8 percent since 2000.[19]

Seismic risk

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The NRC's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Watts Bar was 1 in 27,778, according to an NRC study published in August 2010.[20] The 2018 Southern Appalachian earthquake's epicenter was located two miles east of the facility. The TVA reported that their facilities are designed to withstand seismic events and were not impacted by the earthquake, but personnel would conduct further inspections as a precaution.[21][22][23]

See also

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Notes

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  1. ^ a b Although Unit 2 originally began construction on September 1, 1973, construction was halted on September 17, 1985 due to regulatory and economic factors. Construction was subsequently resumed on October 15, 2007, and the plant was completed on October 19, 2016, 43 years after construction first started (although the plant was only under active construction for 21 of those years).

References

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  1. ^ Gang, Duane W. (August 29, 2014). "5 things to know about TVA and nuclear power". The Tennessean. Nashville, Tennessee. Retrieved 2019-01-07.
  2. ^ "WATTS BAR-1: Reactor Details". Power Reactor Information System. International Atomic Energy Agency. Retrieved July 14, 2018.
  3. ^ a b "Swapping steam generators at Watts Bar". Nuclear Engineering International. 5 April 2023. Retrieved 16 April 2023.
  4. ^ a b c d e Hiltzik, Michael (2017-05-08). "America's first '21st century nuclear plant' already has been shut down for repairs". Los Angeles Times. ISSN 0458-3035. Retrieved 2017-05-09.
  5. ^ a b DiSavino, Scott (March 16, 2012). "TVA cuts contractors at Alabama Bellefonte nuclear site". Reuters.
  6. ^ "WATTS BAR-2". PRIS. International Atomic Energy Agency. June 29, 2013. Retrieved June 29, 2013.
  7. ^ "TVA: Watts Bar Nuclear Plant". Tennessee Valley Authority. February 10, 2008. Archived from the original on February 12, 2012. Retrieved March 14, 2012.
  8. ^ "Mitigation Strategies". nrc.gov. Retrieved 2015-11-09.
  9. ^ "Spent Fuel Pool Instrumentation Order". nrc.gov. Retrieved 2015-11-09.
  10. ^ "TVA Awards Watts Bar, Sequoyah Outage Contract To Westinghouse". nuclearstreet.com. 2016-02-22. Retrieved 2017-03-05.
  11. ^ Mintz Testa, Bridget (27 May 2012). "Three Generations of Nuclear Power Plants in the U.S." About.com. Archived from the original on 10 April 2016. Retrieved 7 March 2017.
  12. ^ "Watts Bar nuclear reactor granted operating license - first new U.S. reactor in 19 years". timesfreepress.com. Retrieved 2015-10-22.
  13. ^ Today — Initial Criticality Archived 2016-06-10 at the Wayback Machine. www.tva.com. Retrieved 23 May 2016.
  14. ^ "Watts Bar power ascension tests completed". www.timesfreepress.com. Time Free Press. 3 October 2016. Archived from the original on 4 October 2016. Retrieved 4 October 2016. The newest unit at the Watts Bar plant near Spring City, Tenn. is now producing more than 1,150 megawatts of electricity ...
  15. ^ Blau, Max (2016-10-20). "First new US nuclear reactor in 20 years goes live". CNN.com. Cable News Network. Turner Broadcasting System, Inc. Retrieved 2016-10-20.
  16. ^ "Electricity Data Browser". www.eia.gov. Retrieved 2023-01-08.
  17. ^ a b "USA awards HEU downblending contract". World Nuclear News. 1 October 2018. Retrieved 3 October 2018.
  18. ^ "NRC: Backgrounder on Emergency Preparedness at Nuclear Power Plants". Fact Sheets. Nuclear Regulatory Commission. January 2009. Retrieved March 14, 2012.
  19. ^ Dedman, Bill (April 14, 2011). "Nuclear neighbors: Population rises near US reactors". NBCNews.com. Retrieved May 1, 2011.
  20. ^ Dedman, Bill (March 17, 2011). "What are the odds? US nuke plants ranked by quake risk". NBCNews.com. Retrieved April 19, 2011.
  21. ^ "Strongest earthquake since 1973 hits East Tennessee". WVLT-TV. December 12, 2018. Retrieved December 12, 2018.
  22. ^ Dedman, Bill (March 17, 2011). "What are the odds? US nuke plants ranked by quake risk". NBCNews.com. Retrieved April 19, 2011.
  23. ^ Hiland, Patrick (2010-09-02). "Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern United States on Existing Plants" (PDF). MSNBC Media. Archived from the original (PDF) on 2017-05-25. Retrieved 2016-10-05.
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