Nuclear Power
Information
Measures against Potential Massive Earthquakes
Settings of Design Basis Earthquake Ground Motions and Licensing
Status
Power station |
Conventional DBGEM (reported to the government in March 2009) |
Revised DGBEM approved by NRA |
---|---|---|
Takahama | 550gal | 700gal |
Ohi | 700gal | 856gal |
Mihama | 750gal | 993gal |
Regarding the setting of design basis earthquake ground motions, we presented plans to take into account the rupture of multiple fault segments, namely FO-A, FO-B, and Kumagawa, and setting the depth of the upper edge of the faults to 3 kilometers below ground level. Based on these plans, we explained that the design basis earthquake ground motion would be 700 gal*1 for Takahama Nuclear Power Station (NPS), 856 gal for Ohi NPS, and 993 gal for Mihama NPS.
Following a review, a license was issued on February 12, 2015 for Takahama, October 5, 2016 for Mihama, and May 24, 2017 for Ohi.
- *1
- Gal: A unit of acceleration which represents the intensity of seismic acceleration of the foundation/building due to an earthquake
Investigation of the F-6 Fracture Zone in the Site of Ohi Nuclear Power Station
![We excavated a trench within the site area to visually examine potential geological variations.](images/jishin_ss01.jpg)
Trench surveys, in which trenches are dug to confirm the existence of geological displacements, and boring surveys were implemented in the Ohi NPS site to verify that the F-6 fracture zone is not an active fault.