Pair of Earthquakes, Tsunami Hit Fukushima Daiichi

A pair of earthquakes hit the Fukushima region today. A magnitude 7.3 followed by a slightly weaker quake hit offshore of Fukushima prefecture in the same area as the 2011 earthquake and tsunami. Current reports are 1 death, 88 injured, 2 million homes without power.

At Daiichi the following damage and events were noted. Expect more damage reports in the following days as they walk down the plant and detect more abnormalities:

  • The water level of the Unit 2 SFP skimmer surge tank had dropped, but the water level drop stopped after a manual stop operation.
    On-site drainage channel monitor increased from 60Bq / L before the earthquake to 230Bq / L. (High alarm value: 1,500Bq / L)
    * This is downstream from the contaminated water tanks and numerous contaminated waste storage lots. 
  • A high or low warning was issued for the spent fuel pool water level of Units 1 to 4, and the lights were turned off at the same time.
    Currently investigating the cause of the alarm.
  • It was found that the power outage on the 500kV Tomioka Line No. 2 was due to equipment trouble on the Shin Fukushima substation side.
    Since it is difficult to repair, the 500kV Tomioka Line No. 2 will be stopped.
  • The spent fuel pool cooling pumps of Units 1 and 3 were automatically stopped. Cooling of the Unit 3 and Unit 1 spent fuel pools was resumed.
  • The Tomioka Fire Department determined that the operation of the fire alarms in the main office building and the 2nd floor of the Unit 5 turbine building was a “misinformation”.
  • The seismograph values ​​observed at the Fukushima Daiichi Nuclear Power Station and the Fukushima Daini Nuclear Power Station are as follows.
  • Fukushima Daiichi Nuclear Power Station
    Horizontal: 221.3 gal (Unit 6)
    Vertical: 202 gal (Unit 6)
  • Fukushima Daini Nuclear Power Station
    Horizontal: 161.3 gal (Unit 1)
    Vertical: 137.8 gal (Unit 1)
    The 2011 earthquake ground motion readings can be found here for comparison.

We will post follow-up reports as new inspections are completed and further damage is understood. This quake was particularly strong, has already produced multiple aftershocks, and was likely to have caused damage to more vulnerable systems at the plant site.




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