NRA panel confirms assessment on Tsuruga fault

November 19, 2014

NRA panel: Fault under Tsuruga reactor could move

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

Nov. 19, 2014 - Updated 13:04 UTC+1

Experts from Japan's nuclear regulator have determined that a fault running under a reactor at the Tsuruga nuclear plant in Fukui Prefecture, central Japan, could move in the future.

The Nuclear Regulation Authority concluded in May last year that the fault could be active. The plant's operator, Japan Atomic Power Company, then submitted new data disputing that assessment.

But after looking over that data, the NRA's panel of experts on Wednesday reaffirmed last year's conclusion that the fault could shift again.

In its draft assessment report, the panel cited a recently discovered fault north of the reactor that appears to extend from the fault under the reactor.

The panel said it couldn't rule out that the new fault had shifted in the past 120,000 to 130,000 years. Based on new regulations, the authority defines a fault that shifted within that period as potentially active. Reactor buildings and other key nuclear facilities are not allowed to be built atop such faults.

The report pointed out that the new fault could be connected to the fault beneath the reactor.

The panel will submit its assessment to the authority after hearing from other experts who did not participate in the discussions.

If the authority does not overturn the panel's assessment, the reactor cannot be restarted and may have to be decommissioned.

Japan Atomic Power Company Vice President Taiki Ichimura criticized what he described as a unilateral assumption, and expressed confidence it would be proved wrong.

He said the company welcomes the opportunity to challenge the panel's assessment.