Chugoku Electric Power Co. is planning to reassess the quake resistance at its Shimane nuclear power station, which is located near an area with 10 active undersea fault lines, according to company sources.

An areal view of Chugoku Electric Power Co.'s Shimane nuclear power station KYODO PHOTO

Chugoku Electric has been aware of the fault lines ranging in length from 6 km to 51 km but considered their potential impact insignificant given their size and distance from the coastal power station in Matsue.

The utility has determined that detailed research using undersea sonar probes is necessary "to retain the trust of local people," a company executive said, following the unexpected damage inflicted on Tokyo Electric Power Co.'s Kashiwazaki-Kariwa nuclear plant in Niigata Prefecture by a powerful earthquake in July.

The move follows an earlier decision by Tepco to conduct sonic and structural surveys of undersea faults near the Kashiwazaki-Kariwa station as well as the Fukushima No. 1 and No. 2 nuclear power plants.

Also behind Chugoku Electric's move was a revision last year to government guidelines on quake resistance at nuclear plants and instructions to power companies to recheck their nuclear facilities.

The Hiroshima-based utility has since been conducting research under these instructions. It has also decided to conduct research on another active fault, this one under the land, after an expert suggested it could be more than twice as long as initially thought.

The Shimane power station has two reactors. A third is under construction. It is scheduled to start operations in 2011.