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Nuclear power in Japan: Fukushima and after

Nuclear power in Japan: Fukushima and after. Richard Tanter Nautilus Institute for Security and Sustainability rtanter@nautilus.org http://www.nautilus.org/about/associates/richard-tanter/publications

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Nuclear power in Japan: Fukushima and after

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  1. Nuclear power in Japan: Fukushima and after Richard Tanter Nautilus Institute for Security and Sustainability rtanter@nautilus.org http://www.nautilus.org/about/associates/richard-tanter/publications Royal Australian Chemical Institute, Health Safety & Environment Group0, at Risk Engineering Society, 1 September 2011

  2. Outline • What happened at Fukushima? • What is the situation at Fukushima now? • What will happen from now on? • What have been the health and environmental consequences? • Why did these events occur? • What is the future of nuclear power in Japan? • What are the implications beyond Japan?

  3. 1. What happened at Fukushima?

  4. Nuclear plants and facilities in Japan

  5. Nuclear power plants in Japan

  6. Unit 4 reactor schematic - NHK

  7. Boiling Water reactor System

  8. BWR reactor vessel

  9. Key sequences at Fukushima No. 1 NPP, 11 March Pre-quake: • Units 1,2,3 operating; • Units 5 and 6 offline in cold shutdown; • Unit 4 offline; defueled November 2010 14.46 Magnitude 9 earthquake 135 km offshore at • Automatic shutdown of Units 1,2, and 3. • Offsite power is lost. • Emergency diesel generators (EDGs) provide coolant power 15.46 14 metre-tsunami breaches plant seawalls and inundates most of the plant • Emergency generators knocked out • Battery powered pumping system starts; fails by March 12. 19.30 Fuel assemblies in Unit 1 completely exposed

  10. Japanese government report to IAEA: Fukushima “worse than meltdown?” Source: “'Melt-through' at Fukushima? / Govt report to IAEA suggests situation worse than meltdown”, Yomiuri Shimbun, 8 June 2011.

  11. Explosions and fires • March 12: • 15.36 Unit 1 hydrogen explosion destroys upper structure exposing fuel pond; 4 workers injured • March 14 • 11.01 Unit 3 hydrogen explosion destroys upper structure exposing fuel pond; 6 workers injured • March 15 • Fire at Unit 4 spent fuel pond • Hydrogen explosion in Unit 2; suspected damage to wet-well in primary containment. • Explosion at Unit 4 spent fuel pond

  12. March 16 Fire at Unit 4 spent fuel pond March 23 Fire reported at base of heavily damaged Unit 3 Spent fuel at Fukushima I NPP Source: Masa Takubo, cited by David Wright, More on Spent Fuel Pools at Fukushima, All Things Nuclear, March 21, 2010

  13. Fukushima I NPP, 2004 Source: Digital Globe, First Watch, Imagery Report, Japan Earthquake/Tsunami, March 2011

  14. Fukushima I NPP, March 12, before explosion of Unit 1 Source: Digital Globe, First Watch, Imagery Report, Japan Earthquake/Tsunami, March 2011

  15. March 13, after explosion of Unit 1 Source: Digital Globe, First Watch, Imagery Report, Japan Earthquake/Tsunami, March 2011

  16. March 14, 1 minute before explosion of Unit 3 Source: Digital Globe, First Watch, Imagery Report, Japan Earthquake/Tsunami, March 2011

  17. March 14, 3 minutes after explosion of Unit 3 Source: Digital Globe, First Watch, Imagery Report, Japan Earthquake/Tsunami, March 2011

  18. March 14

  19. Seawater pump - March 17 Source: Fukushima Daiichi Nuclear Power Station Photos 16, Cryptome.org

  20. Flooded electric equipment room, Unit 6, March 17 Source: Fukushima Daiichi Nuclear Power Station Photos 16, Cryptome.org

  21. Potential steam production by radioactive afterheat Source: Jan Beyea and Frank von Hippel, “Containment of a Reactor Meltdown,” Bulletin of the Atomic Scientists, August/September 1982

  22. BWR nuclear fuel structure

  23. 2. What is the situation at Fukushima now?

  24. State of Fukushima No. 1 NPP, as of August 30:a. reactors and spent fuel Source: Status of countermeasures for restoring from the accident at Fukushima Daiichi Unit 1 through 4. As of August 30th, 2011. (Estimated by JAIF)

  25. Source: Asahi Shimbun 10 August 2011

  26. State of Fukushima No. 1 NPP, as of August 30:b. contaminated water leakage and water storage • Contamination of huge volumes of sea-water and freshwater injected and sprayed into containment buildings and spent fuel ponds • Some released to sea • Most stored onsite in turbine building basement, etc. • Some stored on floating barges • Highly radioactive leakages from damaged reactor pressure vessels and containment vessels • into sea and into groundwater

  27. State of Fukushima No. 1 NPP, as of August 30:c. Site debris and contamination Source: TEPCO, Survey map of Fukushima Daiichi Nuclear Power Station, August 22, 2011.

  28. Key current site operations • Heat exchange of cooling water to CPV/RPV • Decontamination of radioactive water in containment vessel, in flooded areas, and in storage • As of 9 August, 42,000 tonnes processed, but 120,000 tonnes remained on site; expected end-year goal of 200,000 tonnes now unlikely • Reducing/eliminating onsite radioactive hotspots • Covering all four units with steel and plastic to reduce air-borne contamination

  29. Cold Shutdown Process Behind Schedule Source: Fukushima Cold Shutdown Process Behind Schedule, NikkeiNet, 17 August 2011

  30. 3. What will happen from now on? • Units 1-4 to be decommissioned; Units 5-6 unclear • New TEPCO “roadmap” presented to JAEC 31 August • Plastic covering for Units 1-4 to contain airborne radiation matter • Cold shut down by January 2012 ….? • By end-2011will start building ground shield between Units 1-4 and sea • 800 metres long and 20 metres deep • possible extension around whole of Units 1-4 • Removal of fuel from spent fuel ponds 1-4 • Removal of spent fuel from reactors 1-4 • Removal of corium from Units 1,2 and 3 - from RPV and/or CPV • 10-50 years before attempt at reactor/corium removal possible • Decontamination, dismantling and clean-up …. Sometime in the future

  31. Model of plastic coverage for Unit 1 Source: TEPCO, Attachment,Outline of the reactor building covering plan of Unit 1 at Fukushima Daiichi Nuclear Power Station, Press Release

  32. Unit 1 plastic cover: before and after Source: TEPCO, Attachment,Outline of the reactor building covering plan of Unit 1 at Fukushima Daiichi Nuclear Power Station, Press Release

  33. Seaward-side water shield plan Source: TEPCO, Attachment, Basic Design of Water Shield Wall at the Seaside, Press Release 31 August 2011, p. 6.

  34. Seaward-side water shield - schematic cross-section(piles: 1 metre diameter, 14-22 mm. thick, 22-23 metres deep) Source: TEPCO, Attachment, Basic Design of Water Shield Wall at the Seaside, Press Release 31 August 2011, p. 6.

  35. Fukushima No.1 NPP hydrology (pre-quake data) Source: TEPCO, Attachment, Basic Design of Water Shield Wall at the Seaside, Press Release 31 August 2011, p. 7.

  36. Cross-section of hydrology model (pre-quake data) Source: TEPCO, Attachment, Basic Design of Water Shield Wall at the Seaside, Press Release 31 August 2011, p. 7.

  37. Underground water trajectory modelling schematic Source: TEPCO, Attachment, Basic Design of Water Shield Wall at the Seaside, Press Release 31 August 2011, p. 8.

  38. Anticipated underground water levels with seaside-ward water shield in place Source: TEPCO, Attachment, Basic Design of Water Shield Wall at the Seaside, Press Release 31 August 2011, p. 8.

  39. The corium issue: corium lava flow at Chernobyl Source: “Corium”, Tohoku Earthquake & Nuclear Crisis, 3 April 2011, at http://quakerad.blogspot.com/2011/04/corium.html

  40. The corium issue: corium “elephant’s foot uranium fuel flow in Chernobyl NPP basement Source: “Corium”, Tohoku Earthquake & Nuclear Crisis, 3 April 2011, at http://quakerad.blogspot.com/2011/04/corium.html

  41. The corium issue:Three Mile Island NPP Core End-State Configuration Source: “Corium”, Tohoku Earthquake & Nuclear Crisis, 3 April 2011, at http://quakerad.blogspot.com/2011/04/corium.html

  42. 4. What have been the health and environmental consequences? • Immediate injuries and deaths • Longterm radiation illness and mortality • Temporary social disruption from accident consequences • social, economic, psychological • Longterm social consequences • How many former residents can never go back?

  43. Schematic of 31 August accident at cesium decontamination equipment: two workers drenched Source: TEPCO, 1 September 2011

  44. Ionising radiation maximum permissible dose limits (courtesy Prof. Tilman Ruff, Nossal Institute for Global Health) • Average background radiation: 2-3 mSv/y; half due to radon gas • General population: 1 mSv • Japan: women regulated at 5 mSv over 3 mo • 1 mSv/y ~ 0.11 microSv/h • Radiation workers: • 100 mSv over 5 y with no more than 50 mSv in any year • ICRP recommendations accidents/emergencies: • In lower part of 1-20 mSv range for public • Workers – 100 mSv, ICRP up to 500 for volunteers in emergency rescue operations • Post-Fukushima Japan: • 250 mSv/y workers • 20 mSv for public including children • Codex Alimentarius Commission food recommendations based on max 1 mSv/y assuming contaminated food max 10% of diet

  45. Fukushima radiation releases, 11-20 March 2011 (courtesy Prof. Tilman Ruff, Nossal Institute for Global Health) Source:AREVA

  46. Source: TEPCO, Survey map of Fukushima Daiichi Nuclear Power Station, August 22, 2011.

  47. US Fukushima radiation monitoring, to April 29 (courtesy Prof. Tilman Ruff, Nossal Institute for Global Health)

  48. Zoning criteria Belarus 1991 ICRP 111, 2009

  49. Applying Chernobyl evacuation criteria to Fukushima Red and most yellow is > Chernobyl relocation zone (>1480 kBq/m2) Rest of yellow, green, light blue and some dark blue is > Chernobyl dose reduction zone Cs 137 T1/2 =30 years (courtesy Prof. Tilman Ruff, Nossal Institute for Global Health)

  50. Protective measures • Evacuation for est ext >50 mSv • 20 vs 80 km; late – still ongoing to ?end June • Sheltering – for ext est >10mSv, esp 20-30 km zone • Acceptance increased exposures • Stable iodine – appears not used? • initial evacuation completed by time instruction issued VII-9 GOJ IAEA subm 6.11) • Food and water monitoring and restrictions • Local monitoring • Remediation – including local initiative eg schools • Long-term health assessment planned – details sparse

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