Japan’s Nuclear Regulation Authority (NRA) has labeled a second power plant at great risk of being located above an active seismic fault line. Located in Aomori Prefecture, a panel from the independent agency said the Higashidori plant sits above fractured strips of earth. On Monday of this week, the NRA stated the Tsuruga nuclear facility was almost certainly built on faults that had geologically recent movement, and on the same day as the Higashidori findings, Prime Minister Yoshihiko Noda said that would mean the plant would most likely be decommissioned.
Active faults are those that have shown geological movement within the past 120,000-130,000 years. Government regulations say nuclear plants cannot be built atop such fault lines, and if they are discovered to be after, they must be shut down. Kunihiko Shimazaki, the acting head of the NRA, stated on Friday that two-day surveys had shown signs of tectonic movement in the last 100,000 years. The Higashidori plant, operated by Tohoku Electric Power Co., only has one reactor at this point, but plans were in place to add three more before all nuclear plants were suspended after the Fukushima disaster.
In regard to its decision about the Tsuruga plant, in Fukui Prefecture, the NRA has made it clear that facilities built over active faults will not be permitted to restart. Shimazaki says the agency hasn’t made a final ruling over Higashidori, but they will by next week. This is the third nuclear plant the NRA has inspected so far, following Tsuruga, and the Oi facility, also in Fukui, which is home to Japan’s only two active reactors. The panel that inspected Oi still hasn’t decided if the fault lines it found there are potentially active or not.