Posted by Jim Rojas on December 25, 2010, 8:16 pm
x wrote:
>> That IS what we are talking about here
> Since you have chosen to trollishly top post, we can't really know
> WHAT you are talking about can we?
>> Since you responded to my statement
>> about grid power nukes, we ARE discussing them.
> Who said we weren't?
>> You haven't changed anything with your vast knowledge of a different style
>> of nuke control sytem as it doesn't apply to land units
> You are welcome to prove your point, but you haven't yet. So far, all
> you have done is show your ignorance.
> What you said is that nukes can't change power quickly so they must be
> used as base load. That is wrong. Nuclear plants are normally ran at
> full power for ECONOMIC reasons, not because they can't respond to
> changes in grid demand.
>>
>> Have a great Christmas.
> You too!
> Vaughn
Don't mind some of the people that post here, they mean well.
Jim Rojas
Posted by Josepi on December 27, 2010, 2:03 am
Third time lucky with your troll BS.
We're done
Since you have chosen to trollishly top post, we can't really know
WHAT you are talking about can we?
Vaughn
Posted by x on December 27, 2010, 4:34 am
> Third time lucky with your troll BS.
Don't know what you mean by "third time" but...
> We're done
Suits me. As always, you are welcome to ignore any or all of my
posts.
Happy holidays!
Vaughn
Posted by daestrom on December 27, 2010, 1:25 am
On 12/24/2010 14:37 PM, Josepi wrote:
> I can't buy you logic on that one.
> Are you stating the nuke subs do not run the engines from batteries?
Steam turbines don't run well from batteries. :-)
On my boats, only the emergency propulsion motor was DC and could run
from battery (only about 5 knots).
Nuc subs can afford a highly enriched fuel that makes the nuclear
physics exceedingly simple to operate. Draw more steam, reactor cools a
couple of degrees and physics makes power rapidly rise until temperature
is restored. Stop drawing steam and exact opposite happens.
Your 'logic' is flawed in that you don't seem to perceive that reactors
don't operate the way you think.
> History has indicated land nukes cannot reduce their output quickly without
> radical measures. When the big blackout happened a few years ago, after the
> nukes had to be emergency stopped, without notice, it took weeks to initiate
> them again and get them functional online. Some lessons there.
The 'lesson' is that commercial nucs don't operate in a frequency
regulating mode. Like all base-load units, they do not try and control
grid frequency. So when loads start shifting and the grid starts
breaking apart, frequency at the generators starts oscillating quit a
bit and the unit trips. If the grid hadn't grown so unstable, they
wouldn't have tripped.
BTW, not all nucs 'took weeks to initiate them again'. True, some did
remain shutdown to repair things, but not all experienced any problems.
Some in up-state NY (NMP2, JAF, Ginna) managed to restart in a very
short time (about 1 day).
Some US nuc types were originally designed for load-following and could
go up/down at respectable rates (up to as much as 5% / minute). But the
*economics* of nucs make this not very practical in this country.
Add to it the regulatory issue that no grid operator is licensed in the
US to change the power of a nuc. This means the grid operator has to
make a phone call to the nuc control room to even begin changing load.
In the middle of a crisis, this time delay just doesn't work.
(nucs of similar design in other countries *are* used in load-following
and cycle up/down every day to support grid ops [France and Taiwan are
two that come to mind])
> If your logic were true there would be no need for coal and other quick
> response energy supplies because the cheaper nukes could adapt t the load
> readily and quickly...they can't.
Again, you've got it wrong. The economics of a commercial nuc is that
only a tiny fraction of their costs is power-level related. It costs
almost the same amount of money to run a nuc at 50% as it does at 100%.
Yet the revenue generated at 50% is obviously 1/2.
Please explain what 'the cheaper nukes' is? If you schedule a nuc to
always run at 50%, the price of its electricity is almost doubled what
it would cost per MWhr when operating at 100%. The O&M are the same,
yet the revenue is 1/2.
Besides, there aren't enough nucs currently to replace all the coal
plants, regardless of operational capabilities. (remember, we stopped
building new ones after TMI).
> There must be a different method to waste nuke energy in a submarine, like
> charge batteries or heat sea water. Perhaps the water moderated method you
> mention if you can explain it. Obviously land nukes do not have this luxury.
Nope. The reactor power follows steam demand with almost no rod
control. It's just the physics of a high-enrichment reactor (with
little U-238, the core can be quite small in size so that leakage terms
become very dominant and the temperature coefficient is very negative,
giving very good stability and control).
Once critical in the power range, the physics is such that the reactor
'wants' to remain at one temperature. Raise it by not drawing off steam
and power drops. Cool it by drawing more steam and reactor power rises.
All with no controls and reactor response times are *very* short (can
follow steam transients on the order of just seconds, like going from
all-ahead flank to all-stop and back again).
daestrom
(former EMC Nuclear Submarines)
Posted by Josepi on December 27, 2010, 2:02 am
It would appear that land nukes and sub nikes operate on different concepts
or "politics", if you will.
Thanx for the informative details.
The comment about neks being "cheaper" was in relation to other fuels
producing electricity. I can't be bothered to rehash what it was in retort
to with all the noise.
On 12/24/2010 14:37 PM, Josepi wrote:
> I can't buy you logic on that one.
> Are you stating the nuke subs do not run the engines from batteries?
Steam turbines don't run well from batteries. :-)
On my boats, only the emergency propulsion motor was DC and could run
from battery (only about 5 knots).
Nuc subs can afford a highly enriched fuel that makes the nuclear
physics exceedingly simple to operate. Draw more steam, reactor cools a
couple of degrees and physics makes power rapidly rise until temperature
is restored. Stop drawing steam and exact opposite happens.
Your 'logic' is flawed in that you don't seem to perceive that reactors
don't operate the way you think.
> History has indicated land nukes cannot reduce their output quickly
> without
> radical measures. When the big blackout happened a few years ago, after
> the
> nukes had to be emergency stopped, without notice, it took weeks to
> initiate
> them again and get them functional online. Some lessons there.
The 'lesson' is that commercial nucs don't operate in a frequency
regulating mode. Like all base-load units, they do not try and control
grid frequency. So when loads start shifting and the grid starts
breaking apart, frequency at the generators starts oscillating quit a
bit and the unit trips. If the grid hadn't grown so unstable, they
wouldn't have tripped.
BTW, not all nucs 'took weeks to initiate them again'. True, some did
remain shutdown to repair things, but not all experienced any problems.
Some in up-state NY (NMP2, JAF, Ginna) managed to restart in a very
short time (about 1 day).
Some US nuc types were originally designed for load-following and could
go up/down at respectable rates (up to as much as 5% / minute). But the
*economics* of nucs make this not very practical in this country.
Add to it the regulatory issue that no grid operator is licensed in the
US to change the power of a nuc. This means the grid operator has to
make a phone call to the nuc control room to even begin changing load.
In the middle of a crisis, this time delay just doesn't work.
(nucs of similar design in other countries *are* used in load-following
and cycle up/down every day to support grid ops [France and Taiwan are
two that come to mind])
> If your logic were true there would be no need for coal and other quick
> response energy supplies because the cheaper nukes could adapt t the load
> readily and quickly...they can't.
Again, you've got it wrong. The economics of a commercial nuc is that
only a tiny fraction of their costs is power-level related. It costs
almost the same amount of money to run a nuc at 50% as it does at 100%.
Yet the revenue generated at 50% is obviously 1/2.
Please explain what 'the cheaper nukes' is? If you schedule a nuc to
always run at 50%, the price of its electricity is almost doubled what
it would cost per MWhr when operating at 100%. The O&M are the same,
yet the revenue is 1/2.
Besides, there aren't enough nucs currently to replace all the coal
plants, regardless of operational capabilities. (remember, we stopped
building new ones after TMI).
> There must be a different method to waste nuke energy in a submarine, like
> charge batteries or heat sea water. Perhaps the water moderated method you
> mention if you can explain it. Obviously land nukes do not have this
> luxury.
Nope. The reactor power follows steam demand with almost no rod
control. It's just the physics of a high-enrichment reactor (with
little U-238, the core can be quite small in size so that leakage terms
become very dominant and the temperature coefficient is very negative,
giving very good stability and control).
Once critical in the power range, the physics is such that the reactor
'wants' to remain at one temperature. Raise it by not drawing off steam
and power drops. Cool it by drawing more steam and reactor power rises.
All with no controls and reactor response times are *very* short (can
follow steam transients on the order of just seconds, like going from
all-ahead flank to all-stop and back again).
daestrom
(former EMC Nuclear Submarines)
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> Since you have chosen to trollishly top post, we can't really know
> WHAT you are talking about can we?
>> Since you responded to my statement
>> about grid power nukes, we ARE discussing them.
> Who said we weren't?
>> You haven't changed anything with your vast knowledge of a different style
>> of nuke control sytem as it doesn't apply to land units
> You are welcome to prove your point, but you haven't yet. So far, all
> you have done is show your ignorance.
> What you said is that nukes can't change power quickly so they must be
> used as base load. That is wrong. Nuclear plants are normally ran at
> full power for ECONOMIC reasons, not because they can't respond to
> changes in grid demand.
>>
>> Have a great Christmas.
> You too!
> Vaughn