In March 11, 2011, a magnitude 9.0 earthquake struck at the eastern ocean region of Miyagi Prefecture, Japan. Causing a huge tsunami to hit many prefectures’ bay area and damaging many near shore facilities. One of the severely damaged facility is the Fukushima Daiichi Genshiryoku Hatsudensho, a nuclear power plant located in Fukushima.
There are six boiling water reactors in the Fukushima Power Plant. During the incident reactor 4, 5, and 6 were down for planned maintenance. The automatic earthquake detector system sensed the earthquake and issued an immediate shutdown of the reactors 1, 2, and 3. Due to the shutdown of all reactors and damages caused by the earthquake, the Fukushima Power Plant lost most of its power generating ability and could only rely on its backup diesel power generator to drive the reactor cooling system. Due to the nature of nuclear reaction, the reactors could still be generating heat after shutting down, and it could require a few more days of cooling after its shutdown sequence to prevent its fuel rods from reaching their melting points.
The tsunami hit the Fukushima Power Plant 50 minutes after the earthquake. It was 46 feet high and it ran over the 33 feet seawall like it was nothing. The tsunami soon devoured the power plant and damaged the backup diesel power generator, leaving the power plant with only the backup batteries to drive the cooling system and other vital control components. The battery soon ran out on the following day, and causing the core of the reactors to heat up – leading to catastrophic core meltdown.
TEPCO (Tokyo Electric Power Company) sent in many workers to try to supply power to the failed cooling system, but a few hydrogen-air chemical explosions caused by the extreme heat in all reactor units severely interrupted the rescue mission. The explosion blew a massive hole in the reactor, causing contamination of radioactive materials in the plant’s surrounding. The Japanese government declared emergency and evacuated all residents that are within 20km range of the plant. The Genshiryoku Anzen Hoanin (Nuclear and Industry Safety Agency) categorize the incident as level 7 in the International Nuclear Event Scale, the same level the Chernobyl disaster was rated at.
Following the incident many countries criticized Japanese government’s role and its action of trying to cover-up the incident as a small accident. They condemned the Japanese government’s failure to react when TEPCO clearly didn’t have the situation in control. Contamination around Fukushima was very high, leading to international ban on all products that were imported from the region. The incident also posed dangerous health risk to all workers who were involved in the rescue operation. Approximately 300 workers who entered the plant to save the cooling system absorbed high level of radiation, the exposure level could lead to high probability of cancer related disease’s development in the future of all worker’s lives.
The Japanese government showed high interest towards the clean energy after the incident. Many anti-nuclear organizations emerged as a result, and many public figures also opposed the use of nuclear energy as Japan’s main source of power generation. Japan showed a much higher statistics in installation of solar panel in household. The funding of related renewable energy such as air and ocean also increased dramatically as a result. Although the island still relies most of its power source on nuclear power, the Japanese government showed determination to gradually phase out those power plant in the following centuries.
Resources:
http://www.reuters.com/article/2011/04/12/japan-severity-idUSTKE00635720110412
http://spectrum.ieee.org/tech-talk/energy/nuclear/fukushima-accident-upgraded-to-severity-level-7/
https://www.iaea.org/newscenter/news/fukushima-nuclear-accident-update-log-51