Investigation at Tsuruga continues

December 3, 2012

Experts continue investigation into active faults at Tsuruga plant

http://mainichi.jp/english/english/newsselect/news/20121203p2g00m0dm003000c.html

TOKYO (Kyodo) -- Experts appointed by Japan's nuclear regulatory body on Sunday conducted a field survey for the second day to check whether active faults are running directly underneath the reactors at Japan Atomic Power Co.'s Tsuruga plant on the Sea of Japan coast.

With a major active fault called Urazoko already confirmed to be located around 250 meters from reactor buildings, it is feared that other faults running underneath the reactors could move in conjunction with the Urazoko fault.

If the Nuclear Regulation Authority decides that the reactors are sitting above faults that could move in the future, the plant's Nos. 1 and 2 reactors are unlikely to be allowed to resume operation and may be scrapped.

The experts largely concurred after their field survey the previous day that the Urazoko fault is very activebut they are not yet sure whether the other faults could move in conjunction with the active fault, and conducted further geological checks Sunday.

They are expected to discuss the outcome of their field survey at a meeting to be held on Dec. 10 in Tokyo.

Japan has been reviewing the risk posed by active faults in the wake of the nuclear crisis at Tokyo Electric Power Co.'s Fukushima Daiichi complex, which was triggered by the massive earthquake and tsunami on March 11, 2011.

December 2, 2012

Regulator undecided on nuclear plant fissure

http://www3.nhk.or.jp/daily/english/20121202_24.html

A team of experts from Japan's nuclear regulator has still not decided whether one of the country's reactors stands on an active seismic fault.

The 4-member team from the Nuclear Regulation Authority wrapped up a 2-day survey at the Tsuruga nuclear power plant in Fukui Prefecture on Sunday.

The plant, now offline, is the only nuclear power station in Japan with a confirmed active fault in its compound. The fault is believed to have moved 4,000 years ago.

The team dug the ground near the fault and a nearby fissure called D-1 that runs directly below the Number 2 reactor.

If experts determine that the fissure would move with the fault, the plant cannot be put back online and may have to be scrapped.

This is because the government bans nuclear plant operators from building key facilities above active faults.

Team member Kunihiko Shimazaki said they confirmed that the ground right above the D-1 fissure has changed shape. But he said the team found no evidence that the fault and the fissure would move together.

The team will hold a meeting on December 10th in Tokyo to discuss its findings.

Shimazaki indicated that the nuclear regulator may ask the Tsuruga plant operator to conduct additional inspections or his team may visit the plant again.