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To: justa-hairyape

Excellent posts with the updated information. No power from the grid and 1 of 4 back-up generators has failed.

Presumably they were running 4 generators because they needed 4 generators, and not just for the hell of it. Now they have 3.

Wonder what broke that seems like it was not major, and whether it will seem more important later on.


50 posted on 08/23/2011 2:57:46 PM PDT by Buckhead
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To: Buckhead
They had a similar problem in Japan. When running on just 3 generators, it could mean that current generation may not be optimal. In Japan that caused some spent fuel pools to overheat. And the busy Japanese workers missed the overheating. At any rate - there are now reports of 14 nuclear plants that have reported unusual events (lowest level of concern).

No other power reactors shut automatically, or scrammed, said Diane Screnci, another NRC spokeswoman. Fourteen other nuclear plants declared a Notification of Unusual Event, but remained in operation, she said. These are:

--Carolina Power & Light's Shearon Harris-1, North Hill, North Carolina
--Constellation's Calvert Cliffs-1 and -2, Lusby, Maryland
--Dominion Power's Surry-1 and -2, Surry, Virginia
--Entergy's Palisades, Covert, Michigan
--Exelon's Oyster Creek-1, Forked River, New Jersey
--Exelon's Limerick-1, Limerick, Pennsylvania
--Exelon's Peach Bottom-1 and -2, Delta, Pennsylvania
--Exelon's Three Mile Island-1, Middletown, Pennsylvania
--Exelon's Oyster Creek-1, Forked River, New Jersey
--Exelon's Limerick-1, Limerick, Pennyslvania
--PPL's Susquehanna-1 and -2 Salem Township, Pennsylvania
--PSEG's Salem-1 and -2, and Hope Creek-1 and -2, Hancocks Bridge, New Jersey
--Indiana Michigan Power's Donald C. Cook-1 and 2, Bridgman, Michigan

Earthquake of 5.8 magnitude shuts North Anna nuke plants

51 posted on 08/23/2011 3:10:33 PM PDT by justa-hairyape
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To: Buckhead

I would assume that they have redundancy built into the system, where when the power goes out all the generators start up even thou they don’t need all four. That way if one does fail, their is no delay until the next one comes online. Also they must account for the fact that at some point they must take one off line at a time to change the oil, filters, etc.


55 posted on 08/23/2011 3:43:09 PM PDT by matt04
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To: Buckhead

They are not running 4 generators because they need 4 generators. They’re running 4 generators because the procedure says to run 4 generators. They only need one per reactor, and I’d bet they have a way of cross connecting them to only really need 1 for both. Even if off site power is restored, the procedure probably still calls for them to run. Once off site power is restored, they won’t need them at all.


59 posted on 08/23/2011 4:48:24 PM PDT by wolfpat (Not to know what has been transacted in former times is to be always a child. -- Cicero)
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To: Buckhead

Each unit has two redundant safety trains, i.e. duplicate of everything they need to either shut the plant down safely and/or maintain core temperature. Each safety train has one generator, which by design, is all they need to maintain that unit. Running both trains at the outset of an emergency is likely standard EOP. Loss of one genset does not mean they have inadequate generating capacity. Additionally, they most likey can cross-tie emergency electrical busses across both units, resulting in the availability of 3 gensets, where only two are needed by design for both units. Essentially, they are still up one genset, instead of down one as you imply. 22 years in Nuclear Generation.


69 posted on 08/23/2011 6:09:57 PM PDT by DKM
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To: Buckhead
This website linked below is a little bit on the fringe, but they have put together some interesting points in their article. Just posting it for discussion purpose.

Media Silent On Fate Of North Anna Nuclear Plant At Epicenter Of 5.9 Mineral Virginia Earthquake

79 posted on 08/23/2011 7:50:12 PM PDT by justa-hairyape
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