34 ms·
“ Nukes can operate as peaker plants. The feedback from the control rods is nearly instantaneous.” But the physical thermal stress from throttling it signific
by djsbs 5y ago
“ Nukes can operate as peaker plants. The feedback from the control rods is nearly instantaneous.”
But the physical thermal stress from throttling it significantly shorten its lifespan.
Throttling nukes is not a trivial task; I know one plant (Bruce?) doesn't even bother changing the reactor power, they just inject steam into the bay instead of putto g it through a turbine
- R0b0t1 5y agoSounds like red tape or other stupidity. Ramping up very hot yes, but matching loads like you would with a gas plant no.
- djsbs 5y agoIts a bit complicated. Disclaimer: Im not a nuke engineer, I just took some nuke classes and was surrounded by then for a while. New reactor designs promise to throttle, but I don’t know if any have been deployed. This is a bit more complicated than a gas turbine. With a gas turbine, you just inject more gas as needed to keep the turbine turning at a constant speed. The combustion chamber is a violently small part of the whole. The heat producing part of a reactor, by contrast, is massive. As a result you have thermal gradients, and these gradients are different at different power. They’re also larger at larger power. A large thermal gradient isn’t a huge problem by itself (engineers have been accounting for this since the steam engine). The problem is the change of gradient itself. As the gradient changes, the materials inside change shape and this causes large mechanical stresses. The situation is pretty much the same as when you turn off an ICE car: ever hear those ringing or popping sounds it makes? That is the various hot parts cooling and changing shape abruptly. The problem for a reactor is made worse because material selection is very difficult: you cant just pick any alloy that has good thermal expansion, or good fatigue characteristics. Every alloy must be from a very narrow set of isotopes (not elements!!) that are compatible with the reactor’s neutron environment (balance, distribution, energy spectrum, etc).
- R0b0t1 5y agoI know all of the basic science behind this, but there exist old test reactors that can respond to loads quickly enough to act as peaker plants. Your information is either absolutely ancient or propaganda.
- djsbs 5y agoA throttle-able test reactor can be as simple as a pool with no pressure vessel. There’s maybe 100 of those in univeristies throughout the US. Now commercialize it.
- inter_netuser 5y agoDoes this vary with nuke's design? I'd expect some do better than others.
- djsbs 5y agoSee answer to other comment.
- WalterBright 5y agoShould put a bitcoin mine in the power plant to use the excess power.