Roadmap towards Restoration from the Accident at Fukushima Daiichi Nuclear Power Station

Countermeasures against Tsunami Caused by Aftershocks

■ Supposition of Tsunami Caused by an Aftershoc

We supposed that a tsunami would be formed by an 8-magnitude-class aftershock off (in the east of) the focal epicenter of Tohoku - Pacific Ocean Earthquake.

■Areas Flooded with Supposed Tsunami

The tsunami that would be caused by the above aftershock will be smaller compared to the one after the earthquake on March 11th. Nevertheless, it will flow over the south side of the seawall and flood the ocean-side area (near Units 1 to 6), 4 m above sea level, as well as the south part of the area where the major buildings are located (near Units 3 and 4), 10 m above sea level.

■Countermeasures against Tsunamis

We will construct a temporary seawall, which is higher than the supposed tsunami, at 10 m above sea level. At the same time, we will take countermeasures to prevent overflowing of the accumulated water (contaminated water) from the vertical shaft.

In addition, we have taken countermeasures such as relocation of the distribution panels and the temporary diesel generators for reactor water injection pumps to a hill, in case a tsunami exceeds the supposed scale.

Overview of Expected Construction Area of Temporary Seawall
at Fukushima Daiichi Nuclear Power Plant

End

Appendix1: (Reference)List of countermeasures against Tsunami(PDF 34.9 KB)

Appendix2: The Structure of Temporary Seawall(PDF 48.4 KB)