Japan Press Weekly

Tweet

2012 July 18 - 24 [NUCLEAR CRISIS]

Experts call for immediate research on faults beneath NPPs

Active faults may run under the Oi and Shika nuclear power plants. Depending on survey results, the two NPPs may be forced to be decommissioned if their sites are found to be inappropriate for nuclear facilities.

Toyo University professor Watanabe Mitsuhisa has pointed out for a long time the possibility that the faults under the Oi plant (Oi Town, Fukui Pref.) are active faults which lie across the routes to provide emergency water supplies and movement due to a quake will bring possible serious damages to the plant.

Imaizumi Toshihumi, a professor at the graduate school of Tohoku University, said, “Lots of shattered faults run beneath the Oi plant. The plant site should be investigated again.”

On July 17, the Nuclear and Industrial Safety Agency (NISA) of the industry ministry held a meeting to hear views from experts. In the meeting NISA said, “Experts’ views that the faults should be resurveyed carry considerable weight. Taking their views into account, we will adopt proper measures.”

However, the Oi plant operator, Kansai Electric Power Company (KEPCO), explained that the company has confirmed the faults are not active.

At the Oi NPP, following the restart of the No.3 nuclear reactor on the first day of the month, the offline No.4 unit will resume operations on July 18. If a reinvestigation of the faults is carried out, it will affect the plant’s operation.

In the hearing, it was also reported that the No.1 nuclear reactor at the Hokuriku Electric Power Co.’s Shika NPP (Shika Town, Ishikawa Pref.) probably stands directly above an active fault.

The power company had argued that faults beneath the plant are unlikely to move. NISA had also accepted the company’s assessment as reasonable.

Following the 3.11 quake, the reassessment of faults was conducted at all NPPs across the country and it was found that it is undeniable that the Shika plant may sit on active faults.

The government’s standards for determining the earthquake-proof safety of NPPs ban the construction of key nuclear facilities like nuclear reactor buildings on active faults.

* * *

On the following day, the Ministry of Economy, Trade and Industry instructed operators at the Oi and the Shika NPPs to conduct resurveys of the faults in question which include excavation surveys.