Over-reaction?
Time will tell.
Almost certainly sensible rules for what to do in an emergency. When you first feel the shake you don't know how big the earthquake is so you drop the control rods and shut down the reactor. Then you see how bad it was and whether anything was damaged. If everything is OK then you restart the reactor.
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In our pussified, over-regulated, fearful, bureaucratic make-work society, need you ask?
Undoubtedly a gross, wholly unnecessary overreaction.
As a lifelong Californian, it sounds like it to me, though a 5.9 is a decent shaker -- enough to put the fear of God in you! It must have scared the willies out of folks who've never experienced a quake before.
But, I would venture to say, hardly enough to cause the shut-down of a power plant, even -- or especially -- a nuclear one. Around here, they're built to withstand quite a lot more than that.
Just my two cents.
Standard safety precaution, I would assume. I'm guessing the plant's seismic sensors aren't aware of the severity of the problem, they just are programmed to shut down the reactor if they sense anything.
Just like the smoke detectors in my house go off every time I try to microwave popcorn. An overreaction? Yes, but standard safety procedure for said smoke detector. ;-)
No just normal caution. Controlled shut downs at not a problem. Moat likely SOP.
Coal power is so dirty and nuclear power is so risky that DC should run only on solar power, wind power and burning bullsh*t. I hear at least one of these is in ample supply.
Could have been automatic.
Most likely shutdown on loss of offsite power than due to damage from the earthquake. Most plants will have to declare a Notification of Unusual Event (NUE) for just having felt the earthquake - gets the reviews and evaluations going. At some level, plants will shutdown automatically for a seismic even - levels depend on what the plant is designed for.
Yes. By the media. For the plant, it was a builtin failsafe: “Both reactors tripped automatically at the time of the quake and shut down.” Even the article says so.
On whose part? Frankly, they did the right thing by shutting down and going to the DG’s. They lost offsite power, meaning even though they were up, there was no way of knowing for how long they’d be able to STAY up. Best to place the plant in a safe condition and go with what you know.
A core-trip is usually automatic in cases such as this.
The U.S. Nuclear Regulatory Commission headquarters in Rockville, Md., is monitoring an Alert at the North Anna nuclear power plant in Virginia, following today’s earthquake in central Virginia. The NRC is also monitoring Unusual Events, the lowest emergency classification, declared at several other Eastern U.S. nuclear power plants. In accordance with agency procedures, the NRC’s regional offices in King of Prussia, Pa., and Atlanta have activated their incident response centers. NRC resident inspectors at the affected nuclear power plants will continue to monitor conditions for the duration of the event. North Anna declared its Alert, the second-lowest of the NRC’s four emergency classifications, when the plant lost electricity from the grid following the quake just before 2 p.m. Tuesday. Power is being provided by onsite diesel generators and the plant’s safety systems are operating normally. Plant personnel and NRC resident inspectors are continuing to examine plant conditions. NRC staff in the Maryland headquarters felt the quake and immediately began checking with U.S. nuclear power plants. The NRC is in direct communications with North Anna and is coordinating its response with other federal agencies. Nuclear power plants are built to withstand environmental hazards, including earthquakes. Even those plants that are located outside of areas with extensive seismic activity are designed for safety in the event of such a natural disaster. The NRC requires that safety significant structures, systems, and components be designed to take into account the most severe natural phenomena historically reported for the site and surrounding area. Plants declaring Unusual Events, which indicate a potential decrease in plant safety, include Peach Bottom, Three Mile Island, Susquehanna and Limerick in Pennsylvania; Salem, Hope Creek and Oyster Creek in New Jersey, Calvert Cliffs in Maryland, Surry in Virginia, Shearon Harris in North Carolina and D.C. Cook and Palisades in Michigan. All these plants continue to operate while plant personnel examine their sites.
ref: http://www.nrc.gov/reading-rm/doc-collections/news/2011/11-153.pdf
*groan*
No, an appropriate precaution, assuming the plant was designed to the worst-case earthquake environment for the area, which might have been a 7.0. A 5.9 EQ would have a a chance of being a foreshock to be followed by a 7.0-7.5 EQ near the plant design limits. If you look at the Japan EQ, there were 7.0 level foreshocks that should have led the Fukushima Daiichi ower plant to be fully shut down as a precaution. Would not have prevented all that ultimately happened, but some.
I would not be surprised if the cautionary protocols at US nuke plants has been tightened accordingly. Better to have your pizzas thaw a bit than having to deal with the irrational radiation panics that the media lived on for a good while after the Japan EQ.