Let's see what happens with the Tsuruga plant

January 28, 2013

National 

Active fault to scuttle Tsuruga plant

NRA findings may cost Japan Atomic Power dearly

by Kazuaki Nagata 

Staff Writer

http://www.japantimes.co.jp/news/2013/01/28/national/active-fault-to-scuttle-tsuruga-plant/#.UQZwfPL1tEs

The quake fault running under reactor 2 at the Tsuruga nuclear power plant in Fukui Prefecture is probably active, a panel from the Nuclear Regulation Authority stated in a draft report Monday, effectively condemning the two-reactor complex.

The report, compiled from the panel’s search for potentially active faults at the Tsuruga plant, is a heavy blow to Japan Atomic Power Co., which may have to scrap the reactor at great cost.

“If new knowledge is obtained, the judgment could be reviewed. However, at least at this point, the fault at the plant site is highly likely an active fault that needs to be considered in terms of seismic design,” the report said.

The draft report said the fault or zone of small rocks and sediment called D-1 could move simultaneously with a major active fault called the Urazoko, which is about 200 to 300 meters from the reactor buildings.

If that happens, “it could impact the critical facility right above,” the report said.

The report pointed out that the D-1 zone is possibly an extension of the K fault, which showed traces it has moved within the past 130,000 years or so.

It also said the K fault would probably move together with the Urazoko fault.

The safety guidelines for nuclear power plants do not allow utilities to build reactors or critical cooling equipment directly above an active fault. The guidelines define a fault as active if it has moved within the past 120,000 to 130,000 years. The NRA is planning new rules that will expand that time frame by thousands of years.

During the meeting Monday at which the draft report was submitted, Kunihiko Shimazaki, an NRA commissioner who heads the panel, said the report will be checked by other outside experts before it is finalized.

The panel investigated the Tsuruga site in December, when its experts quickly leaned toward the conclusion that the fault appeared active.

Japan Atomic Power has criticized the panel, saying its view lacks scientific support.

NRA chief Shunichi Tanaka has said the Tsuruga plant’s No. 2 reactor will not undergo the safety exam required to be restarted if D-1 is active, because the unit will no longer be allowed to operate.

The Tsuruga plant has two reactors, with two faults also running under reactor 1, and Japan Atomic Power is still examining them. But reactor 1 is over 40 years old, and the new rules will not allow reactors over 40 to run in principle. The NRA has been examining possible active faults at other plants, including Kansai Electric Power Co.’s Oi atomic plant, also in Fukui Prefecture.

Fault under Tsuruga reactor could be active

http://www3.nhk.or.jp/daily/english/20130128_32.html

An expert panel of the Nuclear Regulation Authority says a fault running under a nuclear reactor on the Sea of Japan coast could be active.

The experts have been examining fissures beneath nuclear power plants. The panel issued their draft report on the Tsuruga nuclear plant in Fukui Prefecture at a meeting on Monday.

The report says a newly found fault under the plant might have moved sometime between 120,000 and 130,000 years ago.

The report says the experts also examined the direction of the fault. This indicates it could be an extension of another fault running directly under the No.2 reactor.

The draft concludes by saying the experts cannot deny the possibility the fault running directly under the No.2 reactor is active.

Government guidelines prohibit building nuclear reactors directly above active faults.

Panel member Kunihiko Shimazaki says it will take more time to complete the final report. He says they are ready to listen to the opinions of other experts, as well as plant operator Japan Atomic Power Company. Shimazaki says learning from others would be helpful in compiling a thorough report.

Nuclear panel to give assessment on fault

      http://www3.nhk.or.jp/daily/english/20130128_15.html

A Nuclear Regulation Authority experts' panel is taking the unusual approach of compiling circumstantial evidence and making a decision from a safety standpoint on the geological conditions under a nuclear power plant.

The panel will caution the authority that a fault running under the Tsuruga plant in Fukui Prefecture could be active. The government's guidelines prohibit building key nuclear facilities directly over active faults.

The authority was created based on the lessons learned from the 2011 Fukushima Daiichi accident. It is allowed to operate independently, without relying on information from the operating power company.

The panel has been collecting circumstantial as well as concrete evidence on faults the government has identified under nuclear facilities.

Meanwhile, the operating power company has reacted to the panel's findings.

On Tuesday of last week, the Japan Atomic Power Company gave the media a look at a survey site at the plant. The utility said it will prove in an additional survey that the fault is not active. The company had earlier submitted an open list of questions to the nuclear authority.

Governor Issei Nishikawa of Fukui Prefecture, which hosts the plant, has released a request for sufficient scientific evidence.

The authority is expected to include older active faults in the new nuclear safety standards it is considering. The tighter standards on active faults could affect nuclear power stations around the nation.

The authority is being asked to explain in detail how it arrived at its decision on the issue, not only to the utilities and local governments concerned, but also to the public to regain their trust in the county's nuclear administration.