4 ms·
They aren't being added to nuclear powerplants because nuclear powerplants have a wide and controllable dynamic range (they can run higher or lower depending)
by DabAsteroid 18y ago
They aren't being added to nuclear powerplants because nuclear powerplants have a wide and controllable dynamic range (they can run higher or lower depending)
Nuclear powerplants, typically, are capital intensive. For this reason, their operators aim for high capacity-factors. Unless economic forces are being ignored, they cannot easily be throttled. They run at 100%, all of the time, except when they are being refueled. The only nation that uses its nuclear powerplants in load-following mode is France -- since such a high proportion, some 80%, of its electricity is nuclear -- and France pays a price for that.
Additionally, it is not mechanically good for a nuclear-powerplant to throttle up and down. Such cycling causes parts to wear-out faster. If it is going to be used at all, it is best to keep it on, at a steady output.
There are other considerations. The nature of reactor poison build-up is such that throttling-up immediately after throttling-down tends, in typical reactor designs, to be difficult to do.
Unlike nuclear-powerplants, hydro and gas-turbine powerplants load-follow well (though the more-efficient gas-turbine powerplants take longer to start-up and might have to burn fuel, idling).
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new [nuclear powerplants] aren't being created.
The United States continuously adds nuclear capacity (through uprates, improved management, refurbishment of previously shut-down reactors, etc.). (http://www.eia.doe.gov/neic/press/images/press191_02-06-1.gif http://www.eia.doe.gov/neic/press/images/press191_02-06-1.gi...)(http://uspowerpartners.org/images/Section2Topic-NuclearEnergy-Graph1.gif http://uspowerpartners.org/images/Section2Topic-NuclearEnerg...) Additionally, up to 33 reactor-units are expected to be on-order there, soon. (http://www.world-nuclear.org/info/inf41.html#preparing http://www.world-nuclear.org/info/inf41.html#preparing) Several reactor-vessels have already been ordered for new reactor-units to be built in the United States. Worldwide, 36 power-reactor-units are under construction, 97 are planned, and 221 are proposed.
http://www.world-nuclear.org/info/reactors.html http://www.world-nuclear.org/info/reactors.html
Japan's nuclear share of its total electricity production (past and projected):
http://www.world-nuclear.org/info/inf79.html http://www.world-nuclear.org/info/inf79.html
2008 30%
2009 37%
2017 41%
2050 60%
It has 3 reactor-units under construction, and 12 more are planned.
South Korea's nuclear share of its total electricity production (past and projected):
http://www.world-nuclear.org/info/inf81.html http://www.world-nuclear.org/info/inf81.html
2006 39%
2017 47%
2035 60%
It has 4 reactor-units under construction, and 4 more are planned.
- DaniFong 18y agoI will confess I know less about fission power plants than you seem to. Good point on the capital intensity. I suppose this does answer why there aren't major flywheel installations are not present at nuclear powerplants. One thought: why aren't there flywheel systems at wind turbines, moderated by a CVT? This would get rid of a lot of transformation losses, and since a motor is unneeded it would be fairly cheap.
- anamax 18y agoNot so fast. Basically everything that you asserted about nuclear plants was wrong. Should we assume that you've gotten that out of your system or ....
- DaniFong 18y agoAm I on trial? What's the question? Let me be more careful. There are two methods to throttle nuclear plants: by control rods, moderating neutron flux, and by temperature, moderating coolant flow (in, say, a pebble bed reactor). Either of these work well for generating heat, though coolant flow is simpler technically. Beyond this the plant is a steam turbine, which would have the same maintenance problems as any other steam turbine designed for the load. It's not as fast as gas, but the fuel is cheaper. But as DabAsteroid pointed out, Nuclear Plant are typically base loaded, in the US at least, so that's not terribly relevant. I don't understand enough of the specifics of the particular designs Dab alludes to to comment on reactor poison buildup. I know that in pebble bed reactors throttling was intended by design. I think that within the US market (which was, erroneously on my behalf, what I assumed the conversation was about), the point of new power plants not being yet created still holds: whatever load balancing one would need is an investment already made. (though this is mostly irrelevant to the point of discussion where nuclear plants don't supply peak demand). Of the proposals for which nuclear plants would supply peak power, the question is still out there: how will they balance the load? There are many possibilities, but they're mostly guesses. There is, increasingly, a diverse market for load balancing technology, and companies, struggling with technology and sales and tradition and economy, to try fill that need.