A Conversation for How a Nuclear Plant Works

Reactor safety and all that

Post 1


Cool article. Nuclear power plants are really interesting if one discounts how incredibly dangerous they are. Plus in the UK you can normally get free trips round them! If you get to the stage of having to use a film badge, wear a watch with a glow-in-the-dark dial. It will give your mates a laugh when they come to check if you're contaminated.

With regard to reactor safety, I would argue that the analogy would be more like conventional power:nuclear power::normal accident events:plane crashes. Nuclear reactors are commonly designed to be fail-safe. For example, fuel rods are held in place using electro-magnets, so that if there is a failure of the internal electrics, the rods get dropped into a big load of cadmium. When accidents do happen, it is usually because of some idiot engineer defeating the safety mechanisms. Therefore, nuclear incidents tend to be low-frequency but high severity. A bit like plane crashes.

What does worry nuclear power stations, in the UK at least, is that shoddy adherence to safety proceedures (causing events not dangerous per se, but of concern wrt future safety) can easily get that plant shut down for a while. And they don't like that very much.

Reactor safety and all that

Post 2


Good analogy. I wish I had used that one instead; I was sort of scraping around for a good analogy between conventional and nuclear power.

At least in the United States, there's something of a safety-concious culture, because plants are answerable to the government in the form of the Nuclear Regulatory Commission (NRC), and therefore the people. We've all seen what happens when plants don't behave in a safety-concious manner; they get ordered to shut down at a monetary loss of over $500,000 per day.

What scares me is the new plants they're building in China. The Chinese government doesn't have nearly as much experience with nuclear power that we do, and they don't have anybody regulating them like the NRC does. Supposedly, they've got ten new plants under construction, which means they're going to have a lot of shoddily-built plants run by inexperienced personnel.

Reactor safety and all that

Post 3

Xanatic(phenomena phreak)

Speaking of glowing watches, you used to be able to buy watches where the "hands" had a radioactive material on them. I think uranium. But they stopped them when they found out you got cancer from wearing them. This was 40 years ago or such. They also made ballets where the dancers wore radioactive suits, so they glowed nicely in the dark. That was a longer time ago.

Reactor safety and all that

Post 4


I think the radioactive material was Tritium, an isotope of hydrogen with 1 proton and 2 neutrons. This is liquid at room temperature and could be mixed with other things to create a glowing yellow paint. It was used in night scopes for guns to highlight the cross hairs and other application such as watches. It was found that it was dangerous because the workers who painted with it used to keep their brushes pointy by sucking them (in retrospect, probably one of the worst things they could of done).
It is now very hard to find things that glow due to radioactivity. I believe it is still possible to get emergency exit signs that are slightly radioactive, but you also need to pay lots of money to the government (UK) if you have them.


Reactor safety and all that

Post 5


Yep, they sure do use tritium to make watch faces and exit signs glow, as well as those other things you mentioned. At the risk of sounding like an annoying person who lives to point out detailed corrections ("the devil is in the details" is a mantra around my workplace), I must point out that tritium is not a liquid at room temperature. Tritium behaves chemically the same as hydrogen, which is a gas at normal temperatures and pressures. Tritiated water (T2O) is a liquid, as are any number of other tritiated compounds (compounds where the hydrogen has been replaced with tritium). But you're right, of course, about them using tritium to make the stuff they deposit on the watch faces and hands to make them glow. Since tritium acts much like hydrogen, all you need is very small amounts of it in place of hydrogen in whatever hydrogenous compounds they put on there. For what it's worth, I found that watch faces used to have zinc sulfide mixed with a radioactive salt (!) but that was too dangerous and banned in the '50s. I'm not sure if watches using tritiated stuff are around much, as you say. But we do have many exit signs in the USA that use tritium - typically 11-12 curies, which isn't all that much.

Glow in the dark

Post 6


You're quite right to point out something as stupid as my statement that tritium is liquid at room temperature. I was probably thinking of heavy water and getting confused. My only defence was I am a work when I write these things, and work instantly turns me into a gibbering idiot.
As to the watches, I have seen them in museums set up under geiger counters so you can compare the radioactivity of various things. The watches are always the most radioactive.


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