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Quake's jolts were double VA nuke plant's design
The magnitude-5.8 earthquake last month in Virginia caused about twice as much ground shaking as a nearby nuclear power plant was designed to withstand, according to a preliminary federal analysis.
Parts of the North Anna Power Station in Mineral, Va., 11 miles from its epicenter, endured jolts equal to 26% of the force of gravity (0.26g) from some of the higher-frequency vibrations unleashed by the quake, said Scott Burnell, spokesman of the Nuclear Regulatory Commission.
An NRC document says the reactors' containment structure was built to withstand 12% of the force of gravity (0.12g.) Dominion, the power company that operates the plant, says parts of the plant can handle up to 0.18g.
Originally posted by loam
Feel safe?
Originally posted by SirMike
Yes, thank you.
Originally posted by OrganicAnagram33
All these recent nuclear incidents makes me wonder whether the builders of these plants knew of the potential dangers. It seems logical to check the earthquake record for the area before you build there, and to design the plant to withstand a step above the worst that area has felt. Big fail for big business married to corrupt government. Thanks for the information.
Originally posted by Amaterasu
Originally posted by OrganicAnagram33
All these recent nuclear incidents makes me wonder whether the builders of these plants knew of the potential dangers. It seems logical to check the earthquake record for the area before you build there, and to design the plant to withstand a step above the worst that area has felt. Big fail for big business married to corrupt government. Thanks for the information.
Yeah... That's why California built the San Onofre plant between San Diego and "Shaky Town (LA)."
And several plants are right on the spine of the New Madrid fault.
In fact... It looks as if They were looking for faults to build these on! Either that or They didn't take earth movement as a serious threat...
After Quake, Virginia Nuclear Plant Takes Stock
After weathering the East Coast’s recent quake, the North Anna nuclear plant finds itself in a situation that no American reactor has ever faced before.
The shock was bigger than anything its designers thought it would ever experience —big enough to make 117-ton canisters of spent fuel skitter a few inches on their storage pad.
The situation is so unusual that the Nuclear Regulatory Commission, already facing questions about American earthquake safety after a meltdown at Japan’s Fukushima Daiichi plant, has no protocol in place for determining whether North Annas 1970s design still holds up, post-earthquake.
Originally posted by SirMike
I dont think that is the case.
Little-known U.S. Fault Lines Cause For Seismic Concern About Potential Earthquakes
The New Madrid fault line is centered in the central part of the country and could affect more than 15 million people in eight states. (Alabama, Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri and Tennessee.) But the roughly 1 million people in the metro Memphis, Tenn., region are considered by the U.S. Geological Survey to be at greatest risk from a quake of 7.0 or 8.0. According to an August 2009 report by the U.S. Geological Survey the potential impact could be devastating.
...
There are 15 nuclear power plants in the New Madrid fault zone -- three reactors in Alabama -- that are of the same or similar design as the site in Japan experiencing problems.
There are 15 nuclear power plants in the New Madrid fault zone -- three reactors in Alabama -- that are of the same or similar design as the site in Japan experiencing problems.
Originally posted by loam
reply to post by SirMike
There are 15 nuclear power plants in the New Madrid fault zone -- three reactors in Alabama -- that are of the same or similar design as the site in Japan experiencing problems.
Makes whatever point you seem to be making rather silly doesn't it?
Originally posted by loam
reply to post by SirMikeBut then again, you see what happened in Virginia as a good thing.
North Anna's licensing design basis is 0.12g (peak ground force acceleration) at 100 Hertz (Hz). However, Dominion notes that the plant's design accelerations are significantly higher than 0.12g in the critical range of 2 Hz to 10 Hz, where most earthquake damage is likely to occur. Instruments at the plant indicated that vertical and horizontal motion "very briefly" exceeded 0.12g in the 2Hz to 10 Hz range - by some 12% on average in horizontal direction and by about 21% on average in the vertical direction. The entire earthquake lasted for some 25 seconds, but the peak motion lasted only 3.1 seconds, Dominion said.
Eugene Grecheck, vice president of nuclear development at Dominion, said: "We are seeing exactly what independent seismic experts have told us to expect - minor damage such as insulation that was shaken off some pipes, electrical bushings that will be replaced and some surface cracking on non-seismic qualified walls."
Originally posted by SirMike
Not at all. My point is that based on the seismic hazard map posted above,
Originally posted by SirMike
seismic issues stemming from the New Madrid fault were obviously taken into consideration as there isn’t a unit within 250 miles of the most active areas.
Originally posted by SirMike
While Browns Ferry is of a similar design to Fukushima, it sits about 300 miles away from the coast, not exactly at risk from a Tsunami.
Originally posted by SirMike
Originally posted by loam
reply to post by SirMikeBut then again, you see what happened in Virginia as a good thing.
I certainly do see it as a good thing: a nuclear unit receiving only superficial damage during an event which exceeded certain portions of its deign basis. Do you see this as a bad thing? Would you consider it a “good thing” if the plant suffered some catastrophic failure in a safety related system?
Originally posted by SirMike
North Anna's licensing design basis is 0.12g (peak ground force acceleration) at 100 Hertz (Hz). However, Dominion notes that the plant's design accelerations are significantly higher than 0.12g in the critical range of 2 Hz to 10 Hz, where most earthquake damage is likely to occur. Instruments at the plant indicated that vertical and horizontal motion "very briefly" exceeded 0.12g in the 2Hz to 10 Hz range - by some 12% on average in horizontal direction and by about 21% on average in the vertical direction. The entire earthquake lasted for some 25 seconds, but the peak motion lasted only 3.1 seconds, Dominion said.
Eugene Grecheck, vice president of nuclear development at Dominion, said: "We are seeing exactly what independent seismic experts have told us to expect - minor damage such as insulation that was shaken off some pipes, electrical bushings that will be replaced and some surface cracking on non-seismic qualified walls."
But not that any of this will persuade you. After all, you really only seem concerned with a trivial argument about whether a plant is actually ON TOP OF a known fault within the zone, ignoring the fact that the risk nonetheless remains for catastrophic damage to occur for some if not all of the 15 plants positioned within seismically relevant locations within the zone.
I see luck as a good thing.
I I do not see luck as a sound nuclear regulatory plan.
.
1)25 spent-fuel storage casks — each weighing 115 tons — moved on their concrete pads;
.
2) the plant was designed to withstand 12% of the force of gravity (0.12g.), the plant experienced twice that number;
.
3)by the NRCs own admission, it has no protocol in place for determining whether North Anna's 1970s design still holds up; and
.
4) They are still assessing the situation and have made no final safety or damage conclusions
“Real-world experience trumps all calculations,” said Roger Hannah, a spokesman for the [NRC]. “It provides an opportunity to have real empirical data you can put into the equation, rather than something that’s a computer model.”
The [NRC] has assigned a special team to study the quake’s effects on North Anna, and in the next two years it must determine whether a score of nuclear plants in the eastern United States are earthquake-safe.