Fukushima lady with more internal exposure than external? Uh-oh.

Noticed some hits from freerepublic, checked out the main link-provider, saw another link there to a Fukushima over-exposure.

and one of them was exposed to a total of 17.55 millisieverts of radiation.

The woman was found to have suffered more internal than external radiation exposure, with the internal exposure reaching 13.6 millisieverts.

Since 13.6 isn’t greater than 17.55, let’s assume the internal dose is the sum of those two.  So, 31 mSv (3.1 rem) dose.  That isn’t life-threatening; my highest dose doing nuke outages was 30 mSv one year, give or take a few mSv.  (My lifetime dose is about 82 mSv, almost all of it in my first seven years of work.)

Remember, their emergency response limit is 250 mSv.  Those “beta burn” workers got five or six times more dose than she did.  But we take internal dose very seriously.  How did she get it?

She had been wearing a mask, but may have inhaled radioactive material when putting it on or taking it off.

If you wear a respirator properly, the most likely time to get facial contamination or an uptake is when taking it off.  But are we even sure she was wearing it properly?

And respirators don’t completely eliminate airborne contamination.  They’re rated by PF, Protection Factor.  The given rating for a full-face cartridge type is 50: fifty times more activity in the air than in the respirator.  That’s the lowest acceptable number, and it’s the one used for planning.  In actuality, with a good seal around the skin and knowing how to work in a respirator, you can get over 1,000.

Last thing.  If they do dosimetry the way we do, she hasn’t picked up all of that 13.6 mSv yet.  We assign the “committed dose equivalent” all at once, though it’s for a fifty-year exposure.  This is more accurate than the CDE, but it also assigns all the dose at the very beginning. 

We need much more information to know what this lady’s actual situation is.  You have to look at more than whole-body dose when dealing with uptakes.  Was some of this from I-131, as seems very likely?  Then what’s her dose to the thyroid?  It could be much higher than 31 mSv.

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About wormme

I've accepted that all of you are socially superior to me. But no pretending that any of you are rational.
This entry was posted in Atomic Anecdotes, Nuclear power and radiation. Bookmark the permalink.

5 Responses to Fukushima lady with more internal exposure than external? Uh-oh.

  1. Mountainbear says:

    Seems FOX simply C&Ped parts of the JT article. The wording is exactly the same.
    http://search.japantimes.co.jp/mail/nn20110428a3.html

    As for the mask, all the photos I’ve seen so far with the Tepco crew show that they’re wearing them right. The guys who messed up are cops, who might wear those things once or twice per year for displays and parades.

    I find it interesting that they have 19 women on the ground. So feminazis, how’s that for “equality”? Oh, you don’t like that kind of equality. You don’t like it when women take upon the same dangers as men. Sorry! How could I forget that your “equality” means “special treatment”.

    • wormme says:

      They still don’t have equality of dose, though they’re willing to give pregnant women more than we are. I think our admin limit is 5 mSv (500 mrem) for the entire 9-month term.

  2. bartel says:

    More cowbell!

  3. Sue says:

    They had 19 women until March 23rd, when they reportedly pulled them out. If a woman wants “equality”, Japan is not the place to find it.

    I think the article is trying to say that she was “exposed” to a total of 17.55 mSv, of which 13.6 was “internal”, so 3.95 was “external”. I’m not sure I understand how they are making the distinction or where the figures came from. Since they claim all females were removed from the plant on March 23rd, perhaps the worker was subsequently being surveyed for “contamination” and results were positive? We’ve noticed confusion between “exposure” and “contamination” before.

    I will note that if she was around when one or both of the buildings blew up and there was a lot of dust released, the shock wave could have knocked her against something, causing the mask to gap briefly and she might not have realized it in the stress of the moment. Just a possibility, of course.

    The article also is indicating that all females are legally limited to 5 mSv in three months, simply because of the possibility that someone might get pregnant. This lady was in her 50’s and apparently they are concerned, not because of actual pregnancy, but due to the failure to stay under the limit.

    It sounds like they didn’t raise female workers’ rates to 250 mSv along with the men’s. I have also noticed that they are removing male workers who get over 100 mSv, even though the limit was supposedly raised. So far, the reports seem to indicate that when the original legal limit is verifiably breached, the workers are moved elsewhere.

    • wormme says:

      Yes, they’ve apparently been rotating people out of hot work when they hit 100 mSv. Thirty have reached it so far, including three contractors. Everything else being equal, we always try to equalize dose among workers. I think they still have about 150 of the “Fukushima Fifty”, so there may still be a good margin. We just don’t know if the others are all around 90 mSv or if some are relatively undosed.

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