Free Markets, Free People

Japan’s nuclear plant problems and what they mean – a little context

Right now we’re seeing all sorts of reports come out of Japan as to what is happening at the Fukushima nuclear plants.   All of them are tinged with sensationalism, and many of them contain no context to enable the reader to understand what is being reported in terms of the severity of the problem.  For instance:

Readings reported on Tuesday showed a spike of radioactivity around the plant that made the leakage categorically worse than in had been, with radiation levels measured at one point as high as 400 millisieverts an hour. Even 7 minutes of exposure at that level will reach the maximum annual dose that a worker at an American nuclear plant is allowed. And exposure for 75 minutes would likely lead to acute radiation sickness.

Yes, but what does that mean outside the plant?  And, how many millisieverts an hour do we naturally absorb just going about our daily lives.  Both of those answers would help the reader assess the real danger of such radiation levels.

What you’ll find is that if you take an airplane and fly from say Atlanta to Chicago at 39,000 feet, you can expect to absorb 2 millirems of radiation.

So how does that convert to millisieverts?  You math whiz types can figure it out here with these conversion factors:

  • 1 rem = 10-2 sievert (Sv)
  • 1 millirem (mrem) = 10-5 sievert (Sv)
  • 1 millisievert (mSv) = 10-3 sievert (Sv)
  • 1 millisievert (mSv) = 0.1 rem

To help others, 1 millisieverts equals 100 millirems.  And 1 Sievert equals 1000 millisieverts.  To give you an idea of what the number above means in millisieverts (mSv), we typically absorb 6.2 mSv per year in the US.

Now that number has some context and you can relate it to the danger outlined above.

As to the effect.   Here’s a good table outlining the effects of different levels of absorption:

  • 0–0.25 Sv: None
  • 0.25–1 Sv: Some people feel nausea and loss of appetite; bone marrow, lymph nodes, spleen damaged.
  • 1–3 Sv: Mild to severe nausea, loss of appetite, infection; more severe bone marrow, lymph node, spleen damage; recovery probable, not assured.
  • 3–6 Sv: Severe nausea, loss of appetite; hemorrhaging, infection, diarrhea, skin peels, sterility; death if untreated.
  • 6–10 Sv: Above symptoms plus central nervous system impairment; death expected.
  • Above 10 Sv: Incapacitation and death.

So given the information above, 3 hours at 400 mSv is equivalent to 1.2 Sv.    It’s recoverable but with damage.

As for exposure outside the plant – the levels of radiation drop sharply away from the plant.   So those in the most danger, obviously, are those within the plant trying to contain the problem.  Reports say that most of the plant workers have been evacuated and about 50 continue to battle the problems in the reactors.  Where the problem for the public may occur is if there is a release of radioactive clouds of steam, or through explosions that eject material (think dirty bomb).  And naturally much of the impact would be determined by wind direction.   If it is blowing directly east over the ocean, the cloud would do much less harm than if it blew west over  populated areas of Japan.  Additionally, the materials effect would dissipate as the cloud expanded and traveled.  The possibility of any significant amount of radiation reaching the US, for instance, is not particularly high.

Finally, this article by the NYT is actually a good one for background about the problems the Japanese face and the possible outcomes.   For once, they attempt to keep the reporting less sensational and more focused on relating facts.



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13 Responses to Japan’s nuclear plant problems and what they mean – a little context

  • I wonder how many people were killed or injured by fires following the quake.  How many were electrocuted?
    EVERY form of technology…every means of providing energy for our use…carries risks.  We learn to control them.  In a big enough disaster, a lot of our risk management is lost.  It is reality.
    Atomic power is just another technology, and it is one we will get better at using safely by innovation and USE.

    • But radiation is the boogey man, the same way bacteriological infection is.  It’s invisible (not that electricity ISN’T, but people think they’re going to SEE the sparkies before they get zapped so they can avoid it) and unless you get the killer dose of radiation (and even if you DO) it’s not quick (and so we’re treated to the Hollywood vision of skin falling off and turning into a mutant from X-men..)
      We’ve been programmed to think some kinds of death are worse than others – killed by a bullet?  oh well how sad.
      People aren’t rational about the dangers Rags, it’s the way we are, it makes us a wonderful herd animal.   And our friends in the media aren’t helping by observing we get radiation dosed every day, when we stand next to granite monuments, or lay in the sun or during our flight from Dallas to Denver, or when we carry our ever-active cell phones (that slice, dice, do your laundry, take photos, track your pet and twit at you).
      They don’t trouble us with half-life information (or even what it means), that would take all the fun out of putting RADIATION!!!!!! in the head-lines.  I’ve seen, 3 dozen times now, the headline about Navy personnel being radiated as if they were 15 feet from ground zero at the Trinity site during the test.
      Fear wise, I think we’re about 2 years advanced from yelling “PLAGUE!” and carrying posies in our pockets at every opportunity.

      • Yeah, I’ve said for decades a nuke is just a big bombardment weapon.  I get the “chicken-with-head-cut off” response.  Lots of wing flapping and running around bumping into things.
        There are radiation emitters that throw off radiation that registers on a Geiger Counter, but is too wimpy to penetrate a piece of paper.
        I’m too rational.  It is a flaw, I am told…

        • For years I wanted to stick an ‘addendum’ sticker on cars that had the
          “One nuclear Bomb can ruin your whole day” stickers on them….
          I wanted it to say “Right, A 200 lb iron dumb bomb is much betterl”
          You know, for that matter, a 10 lb weighted anything, unguided, non-reactive, from anything from 40 to 20,000 feet, really would suck too, if it’s path coincided with yours.

          • I remember the little “bomblets”, each a few ounces of inert metal, that we used to drop in great numbers over Viet Nam.
            They were day ruiners…

          • 1000grams. Hmm, sounded large when I ordered it. I don’t think I should bother with these metric booby traps!

  • Very informative. Thanks.

  • I found this anecdote from the blog of Jerry Pournell, the sci-fi writer.
    “I don’t mean to belittle the possibility of some radiation exposure in Japan, but do note that during the weeks when the TMI episode dominated the headlines several people were killed at railroad crossings by coal-bearing freight trains, six miners were killed in coal mine accidents, and I make no doubt that there were some severe injuries among oil field workers. Producing energy has a price. Indeed, the late Petr Beckmann in his Access to Energy used to keep track of the fatalities/megawatt for various energy sources: coal, natural gas, nuclear, etc. The source that had the largest number of fatalities per megawatt of energy produced was — rooftop solar power. The fatalities were caused by people falling off the roof while installing or maintaining the collectors. Of course there were not many of those, but there were also not very many megawatts of energy produced, so death per megawatt was very high compared to the next one, which was I think coal. Commercial nuclear was near the bottom, even if you included fatalities in research reactors and those incurred during the development of the atomic bomb (which might be thought of as necessary R&D and thus appropriately factored into the cost of nuclear energy).?

    • Pournell, when he’s gone….great sadness.  He and Niven, top of my favorite writer’s list.

  • Pournelle kicks a$$. I’ve been reading his stuff about the nuclear reactor problems/response/etc and the media coverage.
    Great post with sound information about milliSieverts etc. Thanks! QandO is on top with facts instead of sensationalism.

  • I assume the workers wear special gear that allows them to withstand more radiation, right?

  • I have to wonder if they are trying to hold onto the plants in a functional state, making the situation worse.
    Also, thanks to this, nuclear power is done here.  You almost got some greenies to relent because they don’t produce C02, but the Eco-Luddites who ultimately don’t want us doing anything but crawl into a hole and die will get their way.

  • Isn’t this 400 mSv reading based on radioactive debris blown that was blown into a single detector?
    Also, many cases of long term exposure above what governments consider safe have actually resulted in significantly lower rates of some cancers, with no long term ill effects.  Ann Coulter is a bit snarky, as she usually is, but this article summarizes the evidence well: