NRA confirms experts panel report: Tsuruga sits on active fault

May 22, 2013

Nuclear regulators acknowledge fault below Tsuruga reactor is active

http://mainichi.jp/english/english/newsselect/news/20130522p2g00m0dm084000c.html

TOKYO (Kyodo) -- The Nuclear Regulation Authority on Wednesday accepted an assessment that a reactor at the Tsuruga plant in western Japan is sitting above an active fault, making it increasingly difficult for the facility to resume operation.

"We have received a report from a panel of experts that said there is an active fault...I think there is a need to accept the conclusion sincerely," NRA Chairman Shunichi Tanaka told a meeting attended by other commissioners to discuss the panel's conclusion.

It is the first time Japan's regulatory authorities have acknowledged that an existing reactor is located above a fault feared to move in the future. The judgment may leave plant operator Japan Atomic Power Co. with no option but to scrap the No. 2 reactor.

The NRA also decided to request Japan Atomic Power to study how the spent fuel pool inside the No. 2 reactor building would be affected in the event the fault moves.

Most of Japan's nuclear reactors are currently offline in the wake of the 2011 Fukushima Daiichi complex disaster, and they are required to undergo the NRA's safety assessment process to check whether they satisfy the new regulatory requirements to be introduced in July before they can resume operations.

The NRA, however, is unlikely to go ahead with a safety review for the No. 2 reactor of the two-unit Tsuruga plant given the panel's assessment if Japan Atomic Power submits an application.

The panel, consisting of NRA commissioner Kunihiko Shimazaki and four outside experts, concluded last week that a zone of rock fragments called D-1, running directly beneath the No. 2 reactor, is an active fault, rejecting Japan Atomic Power's objections.

The panel also said the D-1 fault could move together with a confirmed major active fault called Urazoko, which is located about 200-300 meters from the No. 1 and 2 reactor buildings, and may affect facilities located above.

In quake-prone Japan, nuclear power plant operators are not permitted to build reactors and other important safety facilities directly above active faults -- currently defined as those that have moved in the last 120,000 to 130,000 years.

Japan Atomic Power, however, is still conducting its own investigation at the plant to overturn the panel's assessment, while the company's president, Yasuo Hamada, said last week that the company may eventually have to consider taking the issue to court.

Major utilities holding a stake in Japan Atomic Power is closely watching how the issue unfolds, fearing that the company may fall into negative net worth if it has to scrap the No. 2 unit because of shortage of decommissioning funds and loss in asset value.

The company has set aside money for future decommissioning costs on the assumption that the No. 2 reactor will operate for 40 years, but it has been commercially operating for only 26 years.

Restarting Japan Atomic Power's two other reactors is also unlikely to be easy, with the No. 1 unit at the Tsuruga plant known to be aging and a reactor at the Tokai No. 2 plant in Ibaraki Prefecture, eastern Japan, facing local opposition.

Japan Atomic Power is currently surviving on revenues such as basic fees from major utilities that have contracts to receive electricity.

But the utilities may not be able to offer support forever because they are also struggling amid increased fuel costs for thermal power generation to make up for the loss of nuclear power.

NRA: Tsuruga nuclear plant built on active fault

http://www3.nhk.or.jp/nhkworld/english/news/20130522_23.html

Japan's Nuclear Regulation Authority has officially endorsed a report by its expert panel that said a reactor in Fukui Prefecture, central Japan, sits on an active fault.

NRA Chairman Shunichi Tanaka announced the conclusion at a meeting on Wednesday. He said his organization takes seriously the result of the expert panel's probe into the Number 2 reactor at the Tsuruga nuclear power plant, which was released last week.

The government's guidelines ban plant operators from building reactors above active faults due to concerns about damage from earthquakes. The nuclear regulator's conclusion may force Tsuruga plant's operator, Japan Atomic Power Company, to decommission the Number 2 reactor.

The operator says that the NRA's conclusion is unacceptable. The company will carry out its own survey into the fault, and submit the results to the authority by June.

But some participants at the NRA meeting on Wednesday raised concerns that active faults may be overlooked if operators fail to make adequate surveys. They say surveys on faults under other nuclear plants should be reviewed.