On Tue, 09 Oct 2007 22:38:15 GMT, "Vaughn Simon"
wrote:


"Brian Lawson" wrote in message
.. .
, the need for rapid and multitudinous
changes of power required over the course of any 24 hour period
(sometimes as high as 1500 change-orders per shift) and which nuclear
plants at present are not able to modulate. This last item is what
I'm writing about.

That is not true. Nuclear reactors can modulate their output perfectly
well. In fact, a pressurized water reactor (that is the most common type of
reactor) changes power nearly automatically to match demand because of its
negative temperature coefficient .

(Vaughn gets a far away look in his eyes) Back in my nuclear reactor
operator days, I could watch power vary from (say) 10% to well over 50% and not
touch a single control. Larger power changes just took a little bump of the
control rod position.

Commercial nuclear reactors are operated near their full power capacity for
economic reasons, not because they are not capable of being modulated.

Vaughn


Hey Vaughn,

Hmmmmm....so, I wonder...why we still have coal-fired plants, and why
the latest plants built are coal-fired too? Just cost? Just time (to
build)? Just disposal problems? Just politics? Or do you see an
actual purpose for the coal-fired units, at least at present?

And just a question about your statement...

...."I could watch power vary from (say) 10% to well over 50%"

Are you saying a variation of 10% to 50% of full power, or 10 to 50%
of say 80% baseline, was automatically controlled through NTC? Or
would the cooling towers see a fair load shed? And would this power
generation be at the suggested 1500 possible changes per shift? What
am I, and apparently all the people that are debating this here in
Ontario, missing?

Interesting stuff!!

Brian Lawson,
Bothwell, Ontario.