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.