Yes, submarines go from full to minimum to full again in *minutes*. This is possible through the use of very effective neutron poison control and the use of highly enriched fuel.

David

Doesn't is not the same thing as can't.

Is there any incentive for the French nuke plant operators to follow load?

What I call "sane" load following is the cycling you mention. It is insane to throw money down the toilet, which is exactly what you would be doing when diving down in power on a nuke unit to compensate for a thunderstorm turning off the AC.

To classify fossil and nuclear technologies as unable to load follow is disingenuous because a turbine-generator is designed for the application for which it is being used. If some clown wanted to load follow at higher speeds (its all relative) with a nuclear plant, they in theory, could develop a steam turbine with better ramp rates, resistance to high-cycle fatigue, longer outages, etc. Stupid, yes, but entirely possible.

A large portion of the operating costs in nuclear units goes to the engineers working in support of the plant. This makes it uneconomical to ever drop below the unit rating. It also makes nuclear the most economically stimulating form of power generation for a community.

Maybe, but it sure as hell shouldn't.

Alan,I have been following your posts with great interest and find them highly instructive.

Sometimes though I disagree with some info you seem willing to take as definitive.I am by no means a nuclear expert,but I used to live near North Anna in Virginia and worked there on several occasions during maintainence shutdowns and as always I talked to as many people as I could,especially the engineers who were generally willing to take a few minutes to explain the operation of the plant.(The fact that nuclear maintainence work involves a lot of hurry up and wait may explain the engineers free time.)Once I had my initial experience I was able to secure other well paid short term work at some other plants,and enjoyed many a long conversation with other workers every where I went,some of them very well trained specialists.It takes a lot of talk to fill up a twelve hour shift when you may only be needed for an hour or two.

So we talked about everything from proliferation to decomissioning to long term uranium supplies to coon hunting and the humongous bass that lived in the cooling water exit.Unfortunately you had to be cleared by security to fish there,and my job description didn't require me to me to enter that area.In a nuke, you are generally either required to be at a certain place, or else forbidden to go there.For what it's worth,the people I talked to generally thought that the uranium supply would last more or less forever-just like the coal and oil people.They did however acknowledge that at some distant time that breeder reactors might be needed,and did not seem to think that building and running them would be a problem.
Make what you will of this.Oil and coal depletion were mentioned only in passing if at all,but everybody seemed to agree that coal/oil prices would be going up,thereby making the nuke a better long term deal.
I can't remember that the question of reactor type being determined by the need/desire of the feds to control the fuel cycle came up.I could have forgotten by now anyway.

These people generally viewed spent fuel storage and decomissioning as non issues,from an engineering pov.As they saw it,sealing the fuel up in a deep dry salt cavern would take care of the problem if not with absolute safety then safely enough that our future citizens would have numerous other problems of far greater consequence to occupy thier time.As it has worked out,it seems to me that they were quite possibly right....mountiantop removal,ash slurry impoundments failing,global warming induced drought storm rising sea level..you see what I mean?Maybe even a nuclear war(oh the irony!)over oil.

As far as decomissioning goes,thier view was that once you pulled out the fuel,you could pretty well just bury the rest of the plant in a good dry desert and forget it,as any body dumb enough to dig it up would live long enough to regret it,but not a whole lot longer.Or you could just pour the containment building full of good concrete and forget it.Anybody capable of breaking into an ungaurded plant at some far distant time would be capable of doing far worse things, and with much less effort.

Now of course this is nothing less than the worst sort of sacrilege from the anti nuke environmentalist pov,and I personally do not know enough about the RELATIVE risks over the long term have a definite opinion either way.

But let us run the following thought experiment.Let us suppose that we can pour the containment building of a dead nuke full of concrete,weld up the entrances,and pour another few thousand tons of concrete here and there for good measure.Let us pass leglisation to pay for half a dozen around the clock gaurds to keep people off the premises,which would be more than ample,considering that getting into the containment would be literally impossible without a large crew using a great deal of heavy equipment which would have to be driven to the site over public roads. let us suppose that this costs 500 million dollars,which would seem to be ample.

This would free up anywhere from 4 or 5 billion dollars on up to maybe 9 or 10 billion dollars,depending on whose figures you use,to fund more solar,wind,geothermal,biofuel or whatever the best current use happens or seems to be.

Now let us suppose that we do this fifty times,and save 250 billion dollars,which properly invested in renewables,just might be the difference between a soft landing and an uncontrolled crash or worse.

If you step all the way back and look at the big picture,this might not be as farfetched as it sounds.Keep in mind that if we don't get thru the next half century more or less whole,then in centuries to come there will almost certainly be plenty of land and water well removed from any nuclear ruins(of the electricity generating kind,at least!)and probably very few people around anyway.If they are capable of getting in,they would ,one,either know better,or two,as stated above,be capable of worse mischief with less effort imo at least.If somebody ten or twenty thousand years from now gets radiation poisoning,that will be sad,but people will also be getting hit by lightning,murdered by jealous spouses, and maybe eaten by grizzly bears.

Let us also remember that the folks who are howling the loudest about spent fuel storage and nuclear decomissioning costs are the same ones in many cases who are also screaming the loudest about the environmental costs of burning oil and coal,although I must admit some of them have recently seen the nuclear light.

You may safely assume that I think the environmental movement is driven in part by nature worship,and that I don't tend to take shamans and preachers very seriously.I do realize the grave risks we are running of destroying our life support system,and support environmental initiatives that imo will do more good than harm.

If this post doesn't raise a few howls,I am sadly mistaken.Remember,I'm just a crabby old farmer and shouldn't be taken too seriously,except when I comment on agriculture.