HIGASHIDORI, AOMORI PREF – Earthquake faults beneath the Higashidori nuclear power plant in Aomori Prefecture could be active and dangerous, a regulator said Friday.
Nuclear Regulation Authority Commissioner Kunihiko Shimazaki made this revelation at a press conference after a two-day on-the-spot survey of the plant, which currently has one Tohoku Electric Power Co. reactor but, according to plans, will have another one built for the utility as well as two constructed for and run by Tokyo Electric Power Co.
Shimazaki and other survey participants will meet Thursday to consider the results of their probe.
If the regulators suspect the faults are active, it may be difficult for Tohoku Electric to restart the now-offline reactor amid safety concerns stemming from the triple-meltdown disaster at Tepco’s Fukushima No. 1 power plant.
The experts Thursday confirmed four crush zones, including those running near the reactor 1 building. They continued the survey Friday to determine when the zones moved and find out whether there is any possibility they will move again.
Tohoku Electric has offered the explanation that fault slips under the plant site are caused by changes in groundwater levels.
But Shimazaki said Thursday he can’t accept that explanation.
Survey team member Yota Kumaki, a professor at Senshu University, said the same day Tohoku Electric’s claim raises many questions.
Another team member, Hiroshi Sato, a professor at the University of Tokyo, said he can’t understand on what grounds the company drew such a conclusion.
Tohoku Electric maintains there are no active faults beneath the plant and thus there are no safety concerns.
The plant is the third nuclear power station to be inspected by the NRA for possible active faults, following Kansai Electric Power Co.’s Oi plant and Japan Atomic Power Co.’s Tsuruga plant, both in Fukui Prefecture. None of the earlier probes has reached a conclusion.
Following the latest survey, the agency plans to conduct on-site fault studies at Hokuriku Electric Power Co.’s Shika plant in Ishikawa Prefecture, Kepco’s Mihama plant and the Japan Atomic Energy Agency’s Monju fast-breeder reactor, both in Fukui.
118 hot spots delisted
A total of 118 hot spots in Fukushima Prefecture have been taken off the list of areas recommended for evacuation because their radiation levels have fallen below the reference value, the government said Friday.
After three core meltdowns at the Fukushima No. 1 complex tainted much of Fukushima Prefecture and other areas with radiative fallout in March last year, the government urged residents in areas exhibiting an annual radiation dose of 20 millisieverts or more to evacuate.
The 118 spots include 117 in Date and a site in the village of Kawauchi encompassing 129 households. Studies have confirmed that radiation in those areas is now under the 20-millisievert evacuation threshold, the government said.