Showing posts with label North Anna. Show all posts
Showing posts with label North Anna. Show all posts

AP: "Quake risk to reactors greater than thought"

Diposkan oleh Pengetahuan dan Pengalaman on Friday, September 2, 2011

"Gov't says 27 US reactors could be more vulnerable to earthquakes than previously thought", according to the article on 9/2/2011.



From AP:

WASHINGTON (AP) -- The risk that an earthquake would cause a severe accident at a U.S. nuclear plant is greater than previously thought, 24 times as high in one case, according to an AP analysis of preliminary government data. The nation's nuclear regulator believes a quarter of America's reactors may need modifications to make them safer.



The threat came into sharp focus last week, when shaking from the largest earthquake to hit Virginia in 117 years appeared to exceed what the North Anna nuclear power plant northwest of Richmond was built to sustain.



The two North Anna reactors are among 27 in the eastern and central U.S. that a preliminary Nuclear Regulatory Commission review has said may need upgrades. That's because those plants are more likely to get hit with an earthquake larger than the one their design was based on. Just how many nuclear power plants are more vulnerable won't be determined until all operators recalculate their own seismic risk based on new assessments by geologists, something the agency plans to request later this year. The NRC on Thursday issued a draft of that request for public comment.



The review, launched well before the East Coast quake and the Japan nuclear disaster in March, marks the first complete update to seismic risk in years for the nation's 104 existing reactors, despite research showing greater hazards.



The NRC and the industry say reactors are safe as they are, for now. The average risk to U.S. reactors of core damage from a quake remains low, at one accident every 500 years, according to the AP analysis of NRC data.



The overall risk at a typical reactor among the 27 remains very slight. If the NRC's numbers prove correct, that would mean no more than one core accident from an earthquake in about 30,000 years at the typical reactor among the 27 with increased risk.



But emails obtained in a more than 11,000-page records request by The Associated Press show that NRC experts were worried privately this year that plants needed stronger safeguards to account for the higher risk assessments.



(The article continues.)

What's more interesting than the article is the comment section. Here are some:

- I am suspicious of the anti-nuclear propaganda like this article. Not one person died due to the Japanese nuclear problem. Millions of people die worldwide each year due to pollution from coal and oil fired power plants. ... Nuclear power does not produce CO2. It is the ONLY source powerful enough to supply our modern world. Solar and wind are great - but much too small a source. ...The hysteria over nuclear must stop. Every power source has its problems. Nuclear will not kill the five or six billion eventually that scientists say will happen with increasing CO2.



- That's right- Hack Journalist! Blow Me AP! You fear mongoring POS! DIE AP!



- So a bunch of hack journalists read a bunch of government emails and that makes them nuclear engineers?Give me a freaking break!

You can read the rest of the comments at the link.

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North Anna Nuke Plant: Quake May Have Exceeded Nuclear Plant's Safety Specs

Diposkan oleh Pengetahuan dan Pengalaman on Tuesday, August 30, 2011

But don't worry, says NRC, the plant is "less safe", not more dangerous.



From NBC News Washington (8/29/2011):

Despite being built to sustain more than the maximum expected shaking, last week’s earthquake may have exceeded the design parameters of the two nuclear reactors knocked offline.



That conclusion by Dominion Virginia Power and an independent government analysis prompted the Nuclear Regulatory Commission to send inspectors to the nuclear plant in Virginia.



The Dominion-operated North Anna Power Station 12 miles from the epicenter of the 5.8-magnitude quake in Louisa County temporarily lost power, but there was no significant damage to safety systems, according to the NRC. A low-level emergency was declared temporarily Tuesday after the incident.



The additional inspection should not be interpreted to mean the plant is less safe, the commission said Monday.



Nuclear power plants are built with margins of safety beyond the maximum expected shaking, and the damage detected so far at North Anna has been minimal.



(The article continues.)

In the meantime, Japan's Nuclear and Industrial Safety Agency now says there are 14 newly identified active faults near the nuclear facilities in Fukushima and Ibaraki Prefectures: 5 of them around TEPCO's Fukushima I and II Nuclear Power Plants, and 9 around the Tokai II Nuclear Power Plant operated by Japan Atomic Power Company and Tokai Fuel Reprocessing Facility operated by Japan Atomic Energy Agency. (From Kyodo News Japanese, 8/30/2011)



Don't worry, says NISA, they are all minor faults incapable of producing major earthquakes.

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