Pertinent information concerning the Fukushima Dai-ichi NPS accident
Accident outline
Fukushima Dai-ichi Nuclear Accident

On March 11, 2011, an extremely severe accident measuring Level 7 on the International Nuclear and Radiological Event Scale (INES) occurred at the Fukushima Dai-ichi Nuclear Power Station of Tokyo Electric Power Company (TEPCO) in the Tohoku District - off the Pacific Ocean Earthquake and the subsequent tsunami.

Fukushima Dai-ichi NPP (after earthquake and tsunami)
  • In operation
  • The great part of radioactive noble gas was released.
  • Around 1 to 2×1017 Bq of iodine-131 and around 1 to 2×1016 Bq of cesium-137 were released.
Unit 1・2・3
  • In scheduled outage
  • Explosion occurred in the reactor building upper part of unit 4 by the hydrogen considered to have flowed in from unit 3.
Unit 4・5・6
  • Fukushima Dai-ichi Nuclear Accident