The trade and industry ministry's Nuclear and Industrial Safety Agency (NISA) on July 18 ordered Kansai Electric Power Co. (Kepco) and Hokuriku Electric Power Co. to carry out geological surveys, including boring, at the Oi nuclear power plant in Fukui Prefecture and the Shika nuclear power plant in Ishikawa Prefecture, respectively. This is because of suspicions having been raised that fault crushing belts running through the Oi plant site and a fault running through the Shika plant site are active faults.
Even if the two power companies submit benign survey results to NISA, it does not mean that the matter will have been resolved, because the possibility cannot be ruled out that in this quake-prone country, other nuclear power plants are located above or near active faults.
In April, NISA ordered Japan Atomic Power Co. to carry out similar geological surveys in the site of its Tsuruga nuclear power plant in Fukui Prefecture. In early June, before the Oi plant's Nos. 3 and 4 reactors are restarted, experts pointed out the possibility that fault-crushing belts there, composed of stones formed through fault movements, will move together with nearby faults, causing strata sliding on the ground surface.