Fukushima disaster - Chronology

March 11, 2013

Chronology of major events in Fukushima nuclear crisis

http://mainichi.jp/english/english/newsselect/news/20130311p2g00m0dm027000c.html

TOKYO (Kyodo) -- The following is a chronology of events related to the nuclear crisis at Tokyo Electric Power Co.'s six-reactor Fukushima Daiichi nuclear power plant in Fukushima Prefecture, triggered by the earthquake and tsunami on March 11, 2011.

March 11, 2011 -- Magnitude 9.0 earthquake and subsequent tsunami cripple plant, resulting in loss of power at Nos. 1-4 reactor facilities. Government declares nuclear emergency, directing residents in 3-kilometer radius of plant to evacuate.

March 12 -- Prime Minister Naoto Kan inspects plant. Hydrogen explosion occurs at No. 1 reactor building. Government expands evacuation zone to 10-km radius of plant, then to 20-km radius.

March 14 -- Hydrogen explosion occurs at No. 3 reactor building.

March 15 -- Hydrogen explosion occurs at No. 4 reactor building.

March 20 -- Nos. 5-6 reactors achieve cold shutdown.

April 12 -- Government raises nuclear crisis severity level to highest 7 on international scale, on par with 1986 Chernobyl disaster.

April 22 -- Government designates 20-km radius of plant as no-go zone.

June 6 -- The Nuclear and Industrial Safety Agency releases assessment that meltdown occurred at reactor cores of Nos. 1-3 units.

June 27 -- TEPCO starts cooling damaged reactors using water decontaminated through newly installed water treatment system.

Sept. 28 -- Temperatures at bottom of pressure vessels of reactors Nos. 1-3 fall below 100 C.

Dec. 16 -- Government declares state of cold shutdown achieved at plant.

Dec. 21 -- Government and TEPCO announce plan to scrap the plant's Nos. 1-4 reactors in 30 to 40 years.

Feb. 28, 2012 -- Private-sector panel says in report that Kan's response to nuclear crisis created unnecessary confusion.

March 11 -- TEPCO President Toshio Nishizawa issues statement on first anniversary, apologizing again for accident and vowing to continue efforts to keep plant under control.

March 30 -- The government decides to revise its designation of evacuation zones in municipalities near the Fukushima plant.

April 19 -- Nos. 1-4 reactors at the plant are declared defunct, bringing total of Japan's commercial nuclear reactors to 50.

May 5 -- The last of Japan's commercial reactors goes offline.

June 27 -- TEPCO Chairman Tsunehisa Katsumata and President Toshio Nishizawa step down, succeeded by lawyer Kazuhiko Shimokobe and TEPCO Managing Director Naomi Hirose, respectively.

July 1 -- A reactor at Kansai Electric Power Co.'s Oi nuclear power plant in Fukui Prefecture becomes the first in Japan to be reactivated after regular checks since the Fukushima crisis. Another unit at the Oi plant is restarted on July 18.

July 5 -- Diet-appointed panel investigating the Fukushima crisis releases a report saying the disaster was "man-made."

July 18-19 -- TEPCO finishes trial removal of two unused nuclear fuel assemblies from a fuel storage pool at the No. 4 reactor of the Fukushima Daiichi plant.

July 23 -- A government-appointed panel investigating the Fukushima disaster releases final report saying TEPCO mishandled its response to the crisis.

July 31 -- TEPCO receives 1 trillion yen in capital injection from a state-backed bailout fund, falling under effective state control.

Aug. 6 -- TEPCO discloses to the media part of the video recordings of its teleconferences in the first days of the nuclear crisis.

Sept. 19 -- Japan launches new nuclear regulatory body known as the Nuclear Regulation Authority.

Jan. 1, 2013 -- TEPCO sets up its Fukushima headquarters to deal with issues stemming from Japan's worst-ever nuclear accident.

March 11 -- Japan marks second anniversary of the triple disaster -- earthquake, tsunami and nuclear crisis.

March 11, 2013(Mainichi Japan)