Fukushima Daiichi Nuclear Power Plant

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.Nuclear Renaissance Threatened as Japan’s Reactor StrugglesBloomberg, published March 2011. Retrieved 2011-03-14. Analysis: Nuclear renaissance could fizzle after Japan quakeReuters, published 2011-03-14. Retrieved 2011-03-14. Japan nuclear woes cast shadow over U.S. energy policy  Reuters, published 2011-03-13. Retrieved 2011-03-14.Nuclear winter? Quake casts new shadow on reactorsMarketWatch, published 2011-03-14. Retrieved 2011-03-14. Will China's nuclear nerves fuel a boom in green energy? Channel 4, published 2011-03-17. Retrieved 2011-03-17. Following the Fukushima nuclear disaster, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.

The nuclear reactors

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.  The reactor had high atomic and earthquake safety levels when it was made, but it is now both old and out of date. No one knew such a bad earthquake 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.  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.

 Unit Type First went atomically 'critical' Electric power generated Reactor supplied by Designed by Built by Fukushima I – 1 BWR-3 October 1970 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 1,380 MW Fukushima I – 8 (planned) ABWR October 2017 1,380 MW

 2011 Fukushima nuclear disaster 

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

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. Back-up  generators were damaged by the tsunami; started at first, but stopped after  1 hour later.Massive earthquake hits JapanWorld Nuclear News, March 11, 2011 2148h GMT (update 8) 

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.

Japan said that they will start releasing radioactive water into the ocean starting in 2023. They said they will continue doing this in segments through the next 40 years.

Reactor and generators damage reports (09.53 UTC, 16-3-2011)
After the back-up diesel generators pumps broke down, emergency batteries ran low after about eight hours. Batteries from other nuclear plants were sent to the site and mobile electric and diesel generators arrived within 13 hours,;  but work to connect portable generating equipment to power water pumps was still continuing. 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.David Sanger and Matthew Wald, Radioactive Releases in Japan Could Last Months, Experts Say The New York Times 13 March 2011

Data estimated by JAIF (Japan Atomic Industrial Forum).

 Status of reactors at 22:00 March 21 JST 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       Primary containment damage level       Core cooling system 1 (ECCS/RHR)       Core cooling system 2 (RCIC/MUWC)       Building damage level (secondary containment)       Environmental effect (measured north of Service Building) 2019 µSv/hour at 15:00, March 21 Pressure vessel, water level       Pressure vessel, pressure       Containment unit pressure       Was seawater injected into reactor core       Was seawater injected into primary containment vessel       Containment unit venting       Spent fuel damage level       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); de facto Level 5 (containment of reactor core has been breached"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 http://edition.cnn.com/2011/WORLD/asiapcf/03/16/japan.nuclear.reactors/index.html  CNN 16 March 2010)

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
Boron

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. France flew 95 tonnes of boron to Japan on 17 March 2011. 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 fire truck water spraying of SFPs.

A 'Sarcophagus tomb' and liquid metal
On 18 March, the Reuters news agency reported 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.Chernobyl Accident Appendix 1  World Nuclear Association 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
The nuclear emergencies at Fukushima Daiichi and other nuclear facilities raised questions about the future of nuclear power. 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". Following the Fukushima nuclear disaster, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.

References

Other websites

 Official site c/o Tokyo Electric Company 東京電力・福島第一原子力発電所 


Media
 Archived photo . Unit 1 is on the Left.

Category:Buildings and structures in Japan
Category:Earthquake engineering
Category:Nuclear power plants
Category:Fukushima Prefecture