Floating Chernobyls

Hmm, I think there are a few people who might be in need of a quick refresher course on nuclear reactor technology.

\’Floating Chernobyls\’ to hit the high seas
\”Floating Chernobyls-in-waiting\” are coming to a sea near you after a major international agreement was signed last week, according to critics of nuclear power.

These ship bourne reactors may or may not be a good idea but Chernobyls they won\’t be.

For what actually caused the real and major problem and Chenobyl was that the graphite in the reactor caught fire. Once the containment had blown off this meant that the fire was spewing all those radioactive isotopes (remnants of the used fuel essentially) into the atmosphere and thus a plume which reached as far as Wales.

Now if this happens on a ship then there\’s a simple answer. Scuttle the ship.

Sure, you get contamination of the water but the ocean\’s a damn big place and the dilution will be such that it would be very difficult to even detect what had happened, let alone measure any effect. After all, a number of reactor cores have been dumped by the Soviets in the Arctic seas in exactly this manner.

Not exactly nice of them (and sure puts paid to that idea that it\’s capitalism that causes pollution) and something we\’d much rather they hadn\’t done: but not, as a matter of scientific fact, all that big a deal either.

As I say, these ships might be good or bad ideas for other reasons but Chernobyl they ain\’t gonna be.

12 thoughts on “Floating Chernobyls”

  1. Not only did the graphite catch fire, but so did the uranium. For they were using uranium metal as fuel, not uranium oxide.

    So not only was it unspeakably badly operated, it was criminally badly designed. Ah, the Socialist Economies, eh?

  2. “…Once the containment had blown off ..”: time to remind ourselves that they didn’t equip Chernobyl with a Containment Building in the western sense i.e. there was no belt-and-braces, just a belt.

  3. One other thing, Tim. Shortly after the explosion it became clear that they had had a steam explosion – you could rule out a nuclear explosion becuase one always designs a nuclear reactor so that a nuclear explosion is plain impossible. But Wikipedia says that it now seems that there was a (small) nuclear “excursion” – i.e. explosion – after the steam explosion, the evidence being in a measured isotope ratio. If so, that means that the reactor design was worse than you could have imagined. Dear God! Anyway, arguments about sea-going nukes should surely turn not on Chernobyl, but on all those fatuous asses who called for the nuking of the leaking BP oil well in the Gulf.

  4. A strong containment vessel might in fact be a bad idea – if a core does start to go off like a nuclear bomb then the best thing is to let it blow itself apart ASAbloodyP – to contain it might allow the nuclear reaction to continue for another 8 thousandths of a second (or whatever), which in nuclear reaction terms can be a very long time and the difference between a small nuclear explosion and a big nuclear explosion.

    Also, graphite moderated cores are inherently unstable compared to water moderated cores, and also lack the “positive void coefficient” of water moderated cores.

  5. Chernobyl wasn’t necessarily “criminally badly designed.” But the design target was not primarily to provide safe energy; the reason for using this inherently unsafe reactor type was that it could be used for making material for nuclear weapons.

    However, for the modern anti-nuclear movement, since these were for the Peace Bombs, the evil thing is not that USSR took these risks to build bombs; the evil thing is nuclear power itself.

    I remember living near smelly the armpit of USSR and watching, with astonishment, the CND demonstrations aimed against the Western weapons. There was a huge stockpile just round the corner, but no one was really interested because they were socialist bombs.

  6. Chernobyl died because its cooling system had a ‘positive void coefficient’. The coolant (water) was also used as a moderator. When the coolant started to boil, and form steam voids, its moderating capability dropped, which caused reactor temperatures to rise, causing more voids. This was a positive feedback. Eventually, the temperature got so high that the coolant started to crack into hydrogen and oxygen on the zirconium fuel rod cladding. This set fire to the graphite core, which then ignited the hydrogen and blew the lid off the primary containment vessel.

    If these reactors are not RBMK type, then they are unlikely to have a positive void coefficient, and thus they are not Chernobyls.

    Tim adds: Your metals trivia of the day: The Soviets used Zr/Nb tubing for the fuel rods, not Zr/Sn as in the west. Of no great import except that that difference meant there was no decent market for offcuts and scrap of the Zr/Nb tubing in the west, meaning that the 60 tonnes I bought once went off to make Al MAG wheels for cars. Still, 60 tonnes at $3 a kg margin…..

  7. Also using graphite cores is inherently unwise due to Wigner energy which is essentially energy stored in the graphite due to defects caused by neutron impacts. When overheated, the graphite releases the stored energy, adding to the heating of the graphite and encouraging ignition of the graphite. Since this defects have different activation energy, as the graphite heats, Wigner energy is released, further heating the graphite, releasing more Wigner energy, etc. etc.
    The Windscale fire of 1957 was partially the result of Wigner Energy. Of course, if you are using a gas-cooled reactor design, you must use a graphite moderator (no cooling water to use as a moderator). In the 50’s, use of a graphite moderator was understandable (the US had a gas cooled reactor with a graphite moderator from the same era–long decommisioned). That the Soviets keep building them is another example of the Triumph of the Proleteriat being not so much a triumph as a shambles.
    Can’t imagine why most American citizens are so upset with the idea of becoming a socialist society. It worked so well in places like Russia, East Germany, Venezuela, China, etc. etc. etc.

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