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Re: [Phys-l] Nuclear Power and the Grid



In a message dated 9/9/2011 7:46:17 P.M. Eastern Daylight Time,
bernardcleyet@redshift.com writes:


On 2011, Sep 09, , at 15:38, Edmiston, Mike wrote:


So what's the point of a reactor shutdown when the external grid power
is lost? Indeed, what in the world would happen in a system where *all*
power is provided by nuclear plants, and there is a grid problem? They all
shutdown, and you can never get any of them running again if external grid
power is a condition of restart. Sounds like you'd have the proverbial
"catch-22."


I'm surprised no one has mentioned that at least two have shut down in TX
due to the fires (or is it NM) and perhaps a Sr. moment, and these are
coal fired.

If the grid is shut down and the generators are feeding in to it what
happens?

bc thinks not shut down, but down to "idling" power.

p.s. if there's a prob. w/ feeding a dead grid, why not feed pumps to
raise water in a storage lake?

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You can't idle a large power plant. A large power plant turbine is
pumping well over a million Horse power into the grid. When all that power has no
where to go the unit must trip off line. all steam flow to the turbine is
stopped and the generator breakers. are tripped open. The power still being
produced by the boiler , or nuclear reactor goes into raising the
temperature and pressure of the steam system. These plants are designed to also
rapidly trip the steam supply systems ,which in the case of nuclear power
is the nuclear reactor itself. Of course all nuclear plants are designed to
take a full load rejection without exceeding any thermal limits.

With regard to pumping water to a higher level to maintain turbine load,
while the system is indifferent to how the power produced is used, it almost
certainly wouldn't be possible to effect the load transition quickly
enough to preclude the need for a full plant shutdown to prevent dangerous
turbine over speed.

Bob Zannelli