Fukushima Daiichi Nuclear Power Plant

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During the 2011 Fukushima nuclear emergency in Japan, three nuclear reactors were damaged by explosions.

Fukushima Daiichi Nuclear Power Plant (also called Fukushima I) is a disabled nuclear power plant in the town of Ōkuma in Fukushima Prefecture, Japan. Fukushima Daiichi was the first nuclear power plant to be built and run only by the Tokyo Electric Power Company (TEPCO).

In March 2011 there were nuclear emergencies at the power plant and some other Japanese nuclear facilities, which raised questions about the future of nuclear power.[1][2][3][4][5] Following the Fukushima nuclear disaster, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.[6]

The nuclear reactors[change | change source]

A panning type typical BWR Mark I Containment, as used in units 1 to 5.

The nuclear reactors for units 1, 2, and 6 were supplied by General Electric, those for units 3 and 5 by Toshiba, and unit 4 by Hitachi. The architectural design for the General Electric's units was done by Ebasco. All of the building work was done by Kajima.[7] Since September 2010, unit 3 has been fueled by MOX fuel|mixed-oxide (MOX) fuel.[8][9] Units 1–5 had/have a Mark 1 type (light bulb shaped torus) containment structure, unit 6 has Mark 2 type (over/under) containment structure.[10]

Unit 1 is a 439 MW boiling water reactor (BWR3) constructed in July 1967. It started to commercially make electricity on March 26, 1971, and was planned to shutdown in March, 2011. It was damaged during the 2011 Sendai earthquake and tsunami.[11] The reactor had a high atomic and earthquake safety levels when it was made, but it is now both old and out of date. No one know such a bad quake could happen in Japan. Unit 1 was designed for a earthquake peak ground acceleration shaking motion of 0.18 g (1.74 m/s2) and a seismic response spectrum based on the 1952 Kern County earthquake.[10] All units were inspected after the 1978 Miyagi earthquake when the seismic ground acceleration was 0.125 g (1.22 m/s2) for 30 seconds, but no damage to the critical parts of the reactor was discovered.[10]

Unit Type[12] First went atomically 'critical' Electric power generated Reactor supplied by Designed by Built by
Fukushima I – 1 BWR-3 October 1970[11] 460 MW General Electric Ebasco Kajima
Fukushima I – 2 BWR-4 July 18, 1974 784 MW General Electric Ebasco Kajima
Fukushima I – 3 BWR-4 March 27, 1976 784 MW Toshiba Toshiba Kajima
Fukushima I – 4 BWR-4 October 12, 1978 784 MW Hitachi Hitachi Kajima
Fukushima I – 5 BWR-4 April 18, 1978 784 MW Toshiba Toshiba Kajima
Fukushima I – 6 BWR-5 October 24, 1979 1,100 MW General Electric Ebasco Kajima
Fukushima I – 7 (planned) ABWR October 2016[13] 1,380 MW
Fukushima I – 8 (planned) ABWR October 2017[13] 1,380 MW

2011 Fukushima nuclear disaster[change | change source]

See also: Fukushima nuclear disaster

In March 2011, soon after the Sendai earthquake and tsunami,[14] the Japanese government cleared people from around the plant and started local emergency laws at Fukushima I.[14] Ryohei Shiomi of Japan's nuclear safety board was worried about the chance of a meltdown at Unit 1.[15][16] The next day, the Chief Cabinet Secretary, Yukio Edano said that a partial meltdown at Unit 3 was "highly possible."[17]

The Nuclear Engineering International group had reported that Units 1, 2 and 3 were automatically shut down. Units 4, 5 and 6 had already been shut down for maintenance.[14] Back-up generators were damaged by the tsunami;[18] started at first, but stopped after 1 hour later.[19]

Japan’s government said it had and a nuclear emergency when the cooling problems happened as the back-up diesel generators broke down. The cooling is needed to remove decay heat even when a plant has been shut down, due to the long term atomic reactions. Hundreds of Japanese troops were said to be trucking generators and batteries to the site.[20]

Reactor and generators damage reports (09.53 UTC, 16-3-2011)[change | change source]

After the back-up diesel generators pumps broke down, emergency batteries ran low after about eight hours.[21] Batteries from other nuclear plants were sent to the site and mobile electric and diesel generators arrived within 13 hours,[22] but work to connect portable generating equipment to power water pumps was still continuing as of 15:04 on 12 March.[23] The diesel generators would normally be connected by switching gears in a basement area of the power station's buildings, but this had been flooded by the tsunami.[24]

Data estimated by JAIF (Japan Atomic Industrial Forum).

Status of reactors at 22:00 March 21 JST[25] 1 2 3 4 5 6
Electrical power output (MWe) 460 784 784 784 784 1100
Type of reactor BWR-3 BWR-4 BWR-4 BWR-4 BWR-4 BWR-5
Operating status at earthquake In service In service In service Outage (defueled) Outage (scheduled) Outage (scheduled)
Fuel damage level 70% damaged 33% damaged Damaged Not damaged Not damaged Not damaged
Primary containment damage level Not damaged Damage suspected Might be "Not damaged" Not damaged Not damaged Not damaged
Core cooling system 1 (ECCS/RHR) Not functional Not functional Not functional Not necessary Not necessary, AC power available Not necessary, AC power available
Core cooling system 2 (RCIC/MUWC) Not functional Not functional Not functional Not necessary Not necessary Not necessary
Building damage level (secondary containment) Severely damaged by explosion Slightly damaged by explosion Severely damaged by explosion Severely damaged by explosion Vent holes drilled in roof Vent holes drilled in roof
Environmental effect (measured north of Service Building) 2019 µSv/hour at 15:00, March 21
Pressure vessel, water level Fuel exposed partially or fully Fuel exposed partially or fully Fuel exposed partially or fully Safe Safe and in cold shutdown Safe and in cold shutdown
Pressure vessel, pressure Stable Unknown Unknown Safe Safe Safe
Containment unit pressure Stable Stable Decreasing Safe Safe Safe
Was seawater injected into reactor core Continuing Continuing Continuing Not necessary Not necessary Not necessary
Was seawater injected into primary containment vessel Continuing To be decided Continuing Not necessary Not necessary Not necessary
Containment unit venting Yes, but temporarily stopped Yes, but temporarily stopped Yes, but temporarily stopped Not necessary Not necessary Not necessary
Spent fuel damage level Unknown, water injection is being considered Unknown, seawater injection was performed on March 20 SFP water level low
Seawater spray continues,
Damage to fuel rods suspected
SFP water level low
Seawater spray continues,
Damage to fuel rods suspected
SFP cooling capacity has been recovered SFP cooling capacity has been recovered
Evacuation zone's radius 20 km from NPS
INES Level 5 (estimated by Japanese NISA and accepted by the international IAEA); Level 6 (estimated by the French nuclear authority and the Finnish nuclear authorities);[26][27][28] de facto Level 5 (containment of reactor core has been breached[29][30])

Later, unit 4 at the nearby Fukushima II Nuclear Power Station was also shut down by the safety systems. Now, a source of off-site power is available but the damage level at the plant is bad.

Proposed long term safety activity[change | change source]

Boron[change | change source]

Tokyo Fire Department water tower; other 'water tower' fire trucks have been deployed to Fukushima.

Officials have thought about putting in or aerial dropping radiation killing boric acid, boronated plastic beads or boron carbide pellets into the spent fuel pools to absorb neutrons.[31] France flew 95 tonnes of boron to Japan on 17 March 2011.[32] Neutron are absorbed by boric acid, which has been injected into the reactor cores, but is unclear if boron was also included with the hose and fier truck water spraying of SFPs.

A 'Sarcophagus tomb' and liquid metal[change | change source]

On 18 March, the Reuters news agency reported[33] that Hidehiko Nishiyama, a spokesman of Japan's nuclear agency was asked about burying the reactors in a sand and concrete tomb, said: "That solution is in the back of our minds, but we are focused on cooling the reactors down."

After the Chernobyl disaster, the atomic safety workmen used 1,800 metric tonnes of sand and clay cover the plant. This created a problem because they were thermal insulators and trapped heat inside.[34] So first a non-evaporating coolant such as a liquid metal has to be put on it. After it has all cooled off a structure such as the Chernobyl Nuclear Power Plant 'sarcophagus tomb'.

Implications[change | change source]

The nuclear emergencies at Fukushima Daiichi and other nuclear facilities raised questions about the future of nuclear power.[1][2][3][4][5] Platts has said that "the crisis at Japan's Fukushima nuclear plants has prompted leading energy-consuming countries to review the safety of their existing reactors and cast doubt on the speed and scale of planned expansions around the world".[35] Following the Fukushima nuclear disaster, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.[6]

References[change | change source]

  1. 1.0 1.1 Nuclear Renaissance Threatened as Japan’s Reactor Struggles Bloomberg, published March 2011. Retrieved 2011-03-14. Archived 14 March 2011 at WebCite
  2. 2.0 2.1 Analysis: Nuclear renaissance could fizzle after Japan quake Reuters, published 2011-03-14. Retrieved 2011-03-14. Archived 14 March 2011 at WebCite
  3. 3.0 3.1 Japan nuclear woes cast shadow over U.S. energy policy Reuters, published 2011-03-13. Retrieved 2011-03-14.
  4. 4.0 4.1 Nuclear winter? Quake casts new shadow on reactors MarketWatch, published 2011-03-14. Retrieved 2011-03-14. Archived 14 March 2011 at WebCite
  5. 5.0 5.1 Will China's nuclear nerves fuel a boom in green energy? Channel 4, published 2011-03-17. Retrieved 2011-03-17.
  6. 6.0 6.1 "Gauging the pressure". The Economist. 28 April 2011. Archived from the original on 2011-05-05. http://www.economist.com/node/18621367?story_id=18621367.
  7. "Nuclear Reactor Maps: Fukushima-Daiichi". Council for Security Cooperation in the Asia Pacific. http://nuctrans.org/Nuc_Trans/locations/daiichi/daiichi.htm. Retrieved March 12, 2011.
  8. "Fukushima to Restart Using MOX Fuel for First Time". Nuclear Street. 2010-09-17. http://nuclearstreet.com/nuclear_power_industry_news/b/nuclear_power_news/archive/2010/09/17/fukushima-to-restart-using-mox-fuel-for-first-time-091704.aspx. Retrieved March 12, 2011.
  9. "Third Japanese reactor to load MOX". World Nuclear News. 2010-08-10. http://www.world-nuclear-news.org/newsarticle.aspx?id=28211. Retrieved March 12, 2011.
  10. 10.0 10.1 10.2 Brady, A. Gerald (1980). Ellingwood, Bruce. ed. An Investigation of the Miyagi-ken-oki, Japan, earthquake of June 12, 1978. NBS special publication. 592. United States Department of Commerce, National Bureau of Standards. p. 123. http://books.google.com/books?id=qEuWntnoZzYC&pg=PA123.
  11. 11.0 11.1 "Nuke database system: fukushima daiichi-1". ICJT Nuclear Training Centre. Archived from the original on 2011-03-14. http://www.icjt.org/plants/uni/a/uni194a.html. Retrieved March 12, 2011.
  12. "Reactors in operation". IAEA. 31 December 2009. http://www-pub.iaea.org/MTCD/publications/PDF/CNPP2010_CD/pages/AnnexII/tables/table2.htm. Retrieved March 12, 2011.
  13. 13.0 13.1 "Nuclear Power in Japan". World Nuclear Association. 2011-02-24. Archived from the original on 2012-02-13. http://www.world-nuclear.org/info/inf79.html. Retrieved March 12, 2011.
  14. 14.0 14.1 14.2 "Japan initiates emergency protocol after earthquake". Nuclear Engineering International. March 11, 2011. Archived from the original on 2011-04-18. http://www.neimagazine.com/story.asp?sectioncode=132&storyCode=2059127. Retrieved March 11, 2011.
  15. "Explosion at Japanese nuclear plant raises fears". Usatoday.Com. Archived from the original on 2011-03-12. http://www.usatoday.com/news/world/2011-03-12-japan-reactor_N.htm. Retrieved March 12, 2011.
  16. "An explosion at a nuclear power station Saturday destroyed a building housing the reactor, but a radiation leak was decreasing despite fears of a partial meltdown". NYPOST.Com. Archived from the original on 2011-03-13. http://www.nypost.com/p/news/international/nuclear_power_station_explodes_in_lMAD34kuD0536Cb4hSAFMP. Retrieved March 12, 2011.
  17. Report: 2nd Japan nuclear meltdown likely under way - World news - Asia-Pacific - msnbc.com Archived 12 March 2011 at WebCite
  18. "Japan Earthquake Update (2030 CET)". IAEA Alert Log. International Atomic Energy Agency. http://www.iaea.org/press/?p=1121. Retrieved March 12, 2011.
  19. Massive earthquake hits Japan World Nuclear News, March 11, 2011 2148h GMT (update 8) Archived 11 April 2011 at WebCite
  20. Vartabedian, Thomas H. (March 11, 2011). "Damage at two Japan nuclear plants prompts evacuations". Los Angeles Times. Archived from the original on 2011-03-17. http://www.latimes.com/news/nationworld/world/la-sci-japan-quake-nuclear-20110312,0,2627198.story.
  21. Inajima, Tsuyoshi; Okada, Yuji (11 March 2011). "Japan Orders Evacuation From Near Nuclear Plant After Quake". Bloomberg Businessweek. http://www.businessweek.com/news/2011-03-11/japan-orders-evacuation-from-near-nuclear-plant-after-quake.html. Retrieved 11 March 2011.
  22. Maugh II, Thomas H.; Vartabedian, Ralph (11 March 2011). "Damage at two Japan nuclear plants prompts evacuations". Los Angeles Times. Archived from the original on 2011-03-12. http://www.webcitation.org/5x8sdYOz0. Retrieved 11 March 2011.; "Japan Earthquake Update (2210 CET)". IAEA Alert Log. International Atomic Energy Agency. 11 March 2011. Archived from the original on 2011-03-12. http://www.webcitation.org/5x8sdYOz0. Retrieved 12 March 2011.
  23. Japan Orders Evacuation From Near Nuclear Plant After Quake - Businessweek
  24. David Sanger and Matthew Wald, Radioactive Releases in Japan Could Last Months, Experts Say The New York Times 13 March 2011
  25. http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300712524P.pdf
  26. UPDATE 1-French nuclear agency now rates Japan accident at 6 | Reuters Archived 15 March 2011 at WebCite
  27. "Harmful Radiation Leak After Japan Explosion". news.sky.com. 2011. http://news.sky.com/skynews/Home/World-News/VIDEO-Japanese-Prime-Minister-Confirms-That-Nuclear-Radiation-Has-Leaked-From-Fukushima-Plant/Article/201001315952404?lpos=World_News_Top_Stories_Header_0&lid=ARTICLE_15952404_VIDEO%3A_Japanese_Prime_Minister_Confirms_That_Nuclear_Radiation_Has_Leaked_From_Fukushima_Plant. Retrieved 15 March 2011.
  28. Japan earthquake: live - Telegraph Archived 12 March 2011 at WebCite
  29. "A part of the containment vessel is broken and it seems like the vapour is coming out from there. So... [it] appears to be that vapour is coming out from the broken part." BBC 16 March 2010 Archived 16 March 2011 at WebCite
  30. http://edition.cnn.com/2011/WORLD/asiapcf/03/16/japan.nuclear.reactors/index.html CNN 16 March 2010
  31. "How would you solve Fukushima?". The Guardian. UK. Archived from the original on 2011-03-17. http://www.guardian.co.uk/world/blog/2011/mar/17/how-would-you-solve-fukushima. Retrieved 17 March 2011.
  32. "France rushes 95 tonnes of boron to Japan". The Straits Times. 17 March 2011. http://www.straitstimes.com/BreakingNews/World/Story/STIStory_646202.html. Retrieved 18 March 2011.
  33. Saoshiro, Shinichi. "Japan weighs need to bury nuclear plant; tries to restore power". Reuters. http://uk.reuters.com/article/2011/03/18/us-japan-fortimeline-march-idUKTRE72H5TG20110318. Retrieved 18 March 2011.
  34. Chernobyl Accident Appendix 1 World Nuclear Association
  35. "NEWS ANALYSIS: Japan crisis puts global nuclear expansion in doubt". Platts. 21 March 2011. http://www.platts.com/RSSFeedDetailedNews/RSSFeed/ElectricPower/6925550.

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