It’s easy to forget how reliant we are on our technologies … until we are unexpectedly deprived of the means to use them, that is.
Deprived by … oooh, let’s say, an electricity grid fault that leads to an automatic shutdown at a nuclear power station and leaves a big chunk of Florida completely blacked out for an evening? [image by dogfrog]
[As a side note, I never knew that nuclear reactors could just be switched off. Disconnected from the grid, sure, but switched off?]
And that’s just one little hardware failure, hence quickly fixed. But imagine for a moment another highly electricity-dependent country, like the UK for example, being hit by some sort of environmental disaster to which it isn’t accustomed, which causes a large number of grid hardware problems which are hard to trace and fix in the absence of the electricity they provide …
… I think we have a potential cookie-cutter techno-thriller movie plot, folks! Now, who shall we cast as the plucky Prime Minister?
Well, not switched off like a light, but I believe nuclear reactors need to be connected to external power supplies as a safety measure. That way, if the reactor failed, there’d still be power to remove the rods and stop fission.
It can be done, and usually is as a safety measure (think difference between Three Mile and Chernobyl), but I’d imagine moving the fuel rods in and out constantly isn’t a good idea.
(Disclaimer: I’m in no way a nuclear anything, although I once went to a nuclear engineering seminar 12 yrs ago in college where I was told there wasn’t a future in it so don’t bother.)
That’s correct. It takes a certain amount of power for a nuclear plant to operate – there are circulation pumps, lights, etc., that need to be kept running. US nuclear plants are required (so far as I am aware) to be able to draw power from the grid to operate these essentials, as a backup to the plant, in case something should happen to the plant’s own generation capacity. The grid power failed, thus, standard procedure is to shut down the nuclear plant so that you avoid a situation where the plant’s own generation might fail, and you would not have that essential backup power available.
It’s a very “belt-and-suspenders” situation, where if you don’t have both, the plant is shut down. Shut down is accomplished in various ways, depending on the type of reactor. In nearly all cases, though, the fuel remains in place, but graphite (or other materials) “control rods” are lowered into place between the fuel rods to stop the reaction. Good designs “fail safe”, meaning that in case of total loss of power, gravity pulls the control rods down into place, stopping the reaction by absorbing the free neutrons. The reaction stops almost instantly. It does take a bit more time for the heat exchanger, turbines, etc., to spin down, though.
Personally, I think that nuclear fission is a very good option for electric power generation for the next few decades, at least. Yes, it has its own problems and challenges, but so do coal, oil, and gas-fired plants, and hydro, tidal, solar, and wind generators. It’s a matter of choosing amongst alternatives. Right now, the fossil fuels are getting expensive; most environmental lobby groups are not going to be allow new hydro projects to be built in most developed countries; tidal, solar and wind are becoming competitive, but produce so little power per unit that it’s tough to build enough of them to produce power on the scale that is needed.
Thanks for confirming my impressions, Anthony.
I wrote a post touching on the benefits of nuclear power, and how some previously anti-nuclear environmentalists have turned towards it as our best short-term alternative: https://futurismic.com/2007/10/30/long-term-energy-solutions-is-nuclear-our-best-option/
I certainly think it is, for the time being.
“But imagine for a moment another highly electricity-dependent country, like the UK for example, being hit by some sort of environmental disaster to which it isn’t accustomed, which causes a large number of grid hardware problems which are hard to trace and fix in the absence of the electricity they provide …”
It is not a fun experience but it happens.