Update on Nuclear Hysteria

I’ve found this blog from MIT’s Nuclear Science and Engineering department to be a great source of information on what’s actually going on in Japan from people who actually know this stuff. Clayton Cramer offers this interesting radiological travel log of a Southwest vacation.

Future Pundit ponders what design changes could have been made. We know from reports that there was an attempt to bring in a mobile generator to provide power for the cooling pumps, but that it did not succeed because of power incompatibility issues. We also know that for at least eight hours after backup power failed, the reactors coolant was circulated successfully by battery power. So we know we have time even in a very dire situation. I’m honestly rather shocked by the idea that there would be a power incompatibility with a mobile generator. I would imagine you could run such a system off standard 480V three phase AC power that any number of industrial mobile generators could provide. This would allow a generator to be trucked or flown in by helicopter, easily connected, and that could provide enough power for critical cooling systems at the plant. Just checking, there are tractor trailer sized generators that can provide up to 1.5 megawatts of power off a diesel engine. That’s enough power to run 1500 homes. I would imagine it would be enough to run emergency systems at a nuclear facility, but maybe I’m wrong about that. If I am, I’d like to understand why.

10 Responses to “Update on Nuclear Hysteria”

  1. Flighterdoc says:

    Japan has weird household power – 100 v, 50 hz or something, but you would think that somewhere on the island they have suitable generators…. And that the military could get them there (perhaps borrowing an LCAC or two from the US military).

  2. Kevin Baker says:

    It depends on the size of the pumps and how they start those pumps.

    Let’s assume the pumps are 500Hp just for grins. They’re then probably 3,300V, 50Hz and draw something like 76 amps. If they are started with full-voltage starters, then they require a minimum of about 450A to start. A generator big enough to provide that much current without excessive voltage sag would be on the order of 2MW. That’s a BIG generator to be portable – semi-trailer sized. Have you seen the conditions of the roads in that area?

    These are, of course, just guesses, but I’ve been at a few power plants, and I’ve seen the size of some of the equipment they have. I don’t think it’s outside the realm of possibility

  3. Windscreen says:

    I think the power incompatibility problem, as reported in mainstream media was incorrect. The best, most logical explanation I’ve read is that the switchgear room, where the connection was to be made and the mains disconnected, was flooded by sea water and effectively ruined. It stands to reason that the switchgear room/building was built to similar standards as the generator buildings.


  4. Sebastian says:

    Wow, OK… so we’re talking big motors and a significant power infrastructure to support them. It’s amazing they can run off batteries then for eight hours. Their battery banks must be seriously impressive.

  5. Harold says:

    Flighterdoc: it’s 100 V throughout the country (according to Wikipedia), 50 Hz in the east (where this happened) and 60 Hz in the west (Kansai, e.g. Osaka, which I learned independently of Wikipedia some time ago).

    Kevin Baker: I gather there are a variety of pumps involved, not all are that huge. One problem I’ve read is that one or more power switching areas were flooded, but that doesn’t explain the multiple accounts of a compatibility problem and of course all this could be wrong as early reports often are. We’ll probably have to wait on the post-mortems N years from now.

  6. Jake says:

    What I thought, based on the stories I read (yes, I know, MSM accuracy is somewhere on the order of “minute of galaxy”) was that the problem was incompatible connectors – i.e., the generators had the wrong plugs. It’s not an issue that would surprise me, considering that on my rescue squad’s crash truck we have a box full of plug adapters just for the various electrical tools we have on board. The number if different ways to connect to power that have been developed just over the last forty years since the plant was built is amazing. Add in what Harold has said about the two different standards in use in Japan and it complicates the issue even more.

    Given the state of chaos at the time, it wouldn’t surprise me if the mobile generators they got were not the ones originally intended for that facility. Whether that happened through maintenance errors (say, upgrading the generators without checking for compatibility with the 40 year old systems at the designated plant), communications errors caused by the disaster, or because the original mobile generators were damaged, destroyed, or inaccessible because of the widespread damage, is something that may not be known for years.

  7. Oakenheart says:

    Wrong connector my ass. In an emergency, if voltage, current and frequency are correct, hardwire it! Had I been onsite it’s what I would have done!

  8. Reputo says:

    The big pumps that are needed for circulation may run on 4160V power. That would be my gut guess.

  9. Ian Argent says:

    My guess is an inapt translation from Japanese to English in the media is to blame for the “incorrect connectors” thing – that’s a fairly subtle phrase when you think about it.

  10. Ash says:

    What genius builds a reactor in a known tsunami area with the electrical substation in the freaking *basement*?

    I’ve looked down into the basement of an abandoned 70’s era pressurized water reactor, and that sucker was deep – and that was only the part I could see above the water line.