Nuclear Regulation Authority probes faultline beneath Oi plant

By Mari Yamaguchi

Nuclear regulators inspected ground structures at the country's only operating nuclear power plant Friday to examine if an existing fault line is active.

The inspection will determine whether the Oi plant in Fukui Prefecture should close. Its No. 3 and No. 4 reactors went back online in July, becoming Japan's only operating reactors after all 50 Japanese reactors went offline for inspection after a March 2011 earthquake and tsunami triggered a meltdown crisis at Fukushima Daiichi nuclear plant.

A five-member team, led by regulatory commissioner Kunihiko Shimazaki, a seismologist, includes four independent seismologists and fault experts. Among them is Toyo University professor Mitsuhisa Watanabe, who initially brought to attention the question over the F-6 fault where he has found a zone of crushed rocks in bedrocks.

If the fault that cuts across the plant is judged active, Oi must be closed. Government's safety guidelines ban a nuclear plant directly above an active fault.

Active faults are also thought to be under several other plants across Japan and are under investigation.

"There were things we learned only by coming to the site," Shimazaki told reporters after finishing the inspection. But the team may need another round of inspection to make a decision, he said.

The experts will meet Sunday to discuss their findings and possibly make a verdict.

The closely monitored inspection would be a major first test for the regulators to gain credibility over a safety decisions.

Safety concerns run deep among the public, which largely turned anti-nuclear since the meltdowns in Fukushima. While regulators are stepping up reactor safety standards and emergency plans for nuclear plant host communities, many people remain highly concerned about fault lines running underneath nuclear plants.

The Oi plant's shattered zone in question won't trigger an earthquake but could move with active faults near the plant's perimeter. If that happens, the movement could damage a water pipe to bring in water to cool reactors in an emergency. The north-south fault cuts between the No. 1-2 reactors and the No. 3-4 pair.

Oi's operator Kansai Electric Power Co, which had earlier failed to produce a document of the suspected fault despite repeated requests, submitted its preliminary findings of a government-ordered internal investigation that they found no further evidence suggesting an active fault.

Before the on-site inspection, top regulator Tanaka said the two operating reactors would have to be shuttered if the F-6 turns out to be an active fault.

Regulators sought to distance themselves from business or political leaders and promised to make a purely scientific ruling.

"Our decision will not be political, social or economic, but purely based on safety," Tanaka said recently.

He also has modified the definition of an active fault, saying any traces of ground movements as far back as 400,000 years ago should be considered active, more than tripling the current definition.

Prime Minister Yoshihiko Noda, who faced massive protests after ordering the restart for the two reactors, told reporters that he would abide by any decision by the regulators.

© Copyright 2012 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

©2021 GPlusMedia Inc.

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"The law prohibits construction of nuclear power plants above active faultlines. if the faultline is determined to be active, the two reactors will have to be shut down."

I bet they're active, and I bet KEPCO knew they were active when building the reactors, but like TEPCO doing the same just feigned they had no idea. I also bet that despite them being active, in all probability, the new Nuclear Regulation Authority will say it's safe and the reactors will NOT be shut down. It's all about the vested interests and padded envelopes, peeps.

2 ( +2 / -0 )

At the time, the trade and industry ministry said there was no need to prevent the restart of the reactors because the faultline was thought to be inactive.

THOUGHT??? How on earth can they guarantee it? Its nature, its like putting a reactor on mount Fuji and say oh its a sleeping volcano. Seriously where do they get these people.

0 ( +0 / -0 )

KEPCO just announced in its interim report on Wednesday the 31st October that the fault 'cannot be considered an active fault', according to NHK.

So now the government has a dilemma on its hands. If they find it is indeed active, and then actually pluck up he courage to say so, they will have to deactivate a perfectly good NPP and what is far worse, they will risk making KEPCO lose face in public.

1 ( +2 / -1 )

Seriously where do they get these people. From the bureaucracy: amakudari.

0 ( +0 / -0 )

"To meet increasing electricity demand in winter. " And they kept telling us demand increased in the summer, so which is true?

1 ( +1 / -0 )


Electricity use peaks twice a year: midsummer and midwinter, for obvious reasons. The winter peak is about 10% higher than that in summer.

0 ( +0 / -0 )

Not in all areas of Japan and depending on whether you are using electricity for heating which I don't so my winter bills are half those of the summer months. The fridge also requires a lower temperature. My water heating and cooking is gas so about the same summer/winter.

3 ( +3 / -0 )

Interesting that the first paragraph says they conducted the probe Friday. (Past tense, but it's still Friday as of this post.) In and out. In fact I read that they went down the same hole that was dug for Wednesday's report.

The result of such a lightning probe can only be one of two things. Rubber stamp. Or drop the anchors. Now we will have to wait two whole days while they type it up. (Due on the 4th apparently.)

0 ( +0 / -0 )



I'm fairly sure the 10% figure (from NHK) is for the nation as a whole.

0 ( +0 / -0 )

"To meet increasing electricity demand in winter. "

I called this excuse ages ago, and it seems despite being unable to prove there would be no power outages in summer without the reactors, they are now once again threatening the public. This whole 'active'/'inactive' thing is ridiculous; it may not be active at this particular moment but could easily BECOME active at ANY time, so there is no less danger. If there's a fault line below it, shut it down -- the only way to be sure you are safe. /

1 ( +1 / -0 )

The winter peak is about 10% higher than that in summer.

The horrible ubiquitous Kurisumasu light up.

there was no need to prevent the restart of the reactors because the faultline was thought to be inactive.

It is inactive most of the time, let's not nitpick, they''ll stop when that starts shaking, like in Fukushima. But at that moment, they will find there are no batteries in the remocon of the reactors and the plant staff will count the spare change in their pockets to go and buy new ones at the kombini...

1 ( +1 / -0 )

Oi reactors 1 and 2 should be shut down at once. The other 2 (3 & 4)...well eventually.

0 ( +0 / -0 )

Active or inactive, the mindset to build a nuclear reactor on a fault line is absurd.

Giving the green light to restart it is also absurd.

Then we have the Govt. spouting nonsense about needing energy for the winter after raging about needing energy for the summer. And yet, only this week, reports were out that it will be a generally mild winter.

But in the mindset of the Japanese, as soon as the mercury is below 20 degrees C. people act like theyre in the midst of a bitter winter, so the Govt. can easily fool the public with the winter energy story.

Still, the story here is the reactors and continuing saga of how this country operates run by such a misfit outfit which is apparently the Government, which bullies and lies to its people.

The reactors won't be switched off whatever the report.

0 ( +0 / -0 )

Why can't they build nuclear reactor's submerged? Sure, it would cost more, but it would be safer, just like off-shore drilling platforms.... Wait..BP explosion comes to mind....never mind, bad idea no matter where a reator is located. Enviroment suffer's, and People have to move away from their home's

-1 ( +0 / -1 )

Get rid of nuclear power. Put large delta shaped wings out at sea in an ocean current, with a cable attached to the ocean floor. Computer adjusts control surfaces to fly wing to the surface. Cable is paid out, spins on board generator, power is produced and lines carry it back to shore. Control surfaces are re adjusted and computer flies wing to the ocean floor. Cable is retracted, spins generator, produces more electricity. Wing can surface for maintenance ... Relocation etc. no radiation, no noise, no pollution. Put ten out there or five hundred.

0 ( +1 / -1 )

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