Japan nuke timeline

The strongest earthquake ever recorded in Japan at a magnitude of 8.9 struck the country on March 11. Below is a timeline of events following the earthquake and tsunami and the effect on nuclear power plants in Japan.


  • The earthquake took place at roughly 2:46 p.m. locally. The epicenter was located about 130 kilometers off the east coast of the island.
  • Eleven reactors shut down in the quake effected area
  • Cooling problem at TEPCO's 4,600 MW Fukushima Daiichi nuclear plant on the northeast coast of Japan. Fukushima Daiichi is a six-reactor plant that uses GE, Hitachi and Toshiba boiling water reactor technology. TEPCO confirms water levels falling inside reactors at the plant and says it is trying to avert the exposure of nuclear fuel rods by restoring power to its emergency power system so that it can pump water inside the reactors.
  • Fire reported at Tohoku Electricity Co.’s 2,100 MW Onagawa nuclear plant, which has since been extinguished. The Onagawa consists of three boiling water reactor units.


  • TEPCO begins releasing pressure from the 460 MW No. 1 reactor at Fukushima Daiichi nuclear plant, the Trade Ministry says.
  • Chief Cabinet Secretary Yukio Edano confirms an explosion (apparently hydrogen) and radiation leak at Fukushima Daiichi.
  • TEPCO plans to fill the leaking reactor with sea water to cool it and reduce pressure in the unit


  • Risk of an explosion at a building housing the Fukushima Daiichi complex where an explosion March 12 blew the roof off another reactor building.
  • TEPCO begins injecting sea water into the No.1 and No. 3 units at Fukushima Daiichi to cool down the reactors and reduce pressure inside reactor container vessels. TEPCO prepares to pump sea water into the No.2 reactor at its Fukushima Daiichi nuclear power plant.


  • TEPCO reports a rise in radiation levels at its Fukushima Daiichi nuclear power plant to government officials.
  • A hydrogen explosion occurred at Unit 3 at 11:01 am local Japan time at the Fukushima Daiichi nuclear power complex and reportedly has not damaged the plant's No.3 reactor vessel.
  • The International Atomic Energy Agency says Japan reported the hydrogen explosion at the No.3 reactor at the Fukushima Daiichi nuclear plan did not damage the primary containment vessel.
  • Jiji news agency says Japanese authorities have safely cooled down two nuclear reactors at the 4,400 MW Fukushima Daini nuclear plant. Fukushima Daini houses four boiling water reactors supplied by Toshiba and Hitachi.
  • TEPCO says water levels inside the Fukushima Daiichi complex's No.2 reactor are almost empty.
    Cooling systems at Units 1, 2 and 3 of the Fukushima Daiichi plant fail adding concern over a possible meltdown.
  • Restoration work in reactor cooling function that was conducted to achieve reactor cold shutdown has been completed and cooling of the reactor has been commenced at 7:13 am local time, March 14th at Unit 2 at Fukushima Daini Nuclear Power Station, which makes it the third reactor at this plant to cool down.
  • Earthquake upgraded from an 8.9 to a 9.0-magnitude.


  • Radiation leaks from Fukushima Daiichi No. 2 after a third explosion at the plant and a fire in a storage pond for used nuclear fuel.
  • About 200,000 people have been evacuated within a 12 mile radius of the plant.
  • A 6.1 magnitude earthquake aftershock shakes the eastern part of Japan, although authorities are reportedly not anticipating significant damage and the risk of another tsunami is low.
  • The International Atomic Energy Agency has said that all units at Fukushima Daini, Onagawa and Tokai nuclear plants are in a "safe and stable" condition.
  • Implementation of rolling blackouts for periods of up to three hours each.

We will have continuing updates on the events in Japan at Power-GenWorldwide.com

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