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Re: "A key lesson here is the importance of the inhaled dose during plume passage. During plume passage, the unmasked, outdoors, inhaled dose will be 100 to 50 times the external dose as measured by a dosimeter"

I infer this is because the dosimeter measures counts from decaying radiative atoms for short times as they pass by, but human lungs trap the radioactive atoms for their longer effective half-life.

In your Table 2 I'd think the beta (electron) component of the external exposure should be nil because the electrons don't penetrate epidermis, while lung tissue has no such barrier.

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Oct 29·edited Oct 29

I've been hosting a debate on LNT in the FaceBook forum Renewable vs Nuclear Debate. One of the anti-nukers commented that inhaled radiation was very different than external, sparsely ionizing radiation, and would probably follow LNT due to the particles that get stuck in the lung. I haven't seen any counter argument, but perhaps this data on Fukushima workers would do it.

Do we have any information on the nature of these particles? Are they just isolated iodine atoms floating in the air, or more like an aerosol with thousands of atoms in a small cluster? The concentration of radiation from one particle in a small volume of tissue could overwhelm any hormetic response.

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I'm guessing he's talking about the "hot particle" theory. This was a big deal in the early 1970's when it was raised in relationship to plutonium. There have been plenty of counter-arguments. The theory was investigated pretty thoroughly with animal studies, and the results were negative. Also contradicted by 25 Los Alamos workers who inhaled a bunch of Pu dust. According to the 'hot particle" theory, each had a 99.5% chance of mortal cancer. but none were observed. See Cohen, The Nuclear Option, p 249-250.

Cohen points out that particles in the lung don't stay in one place. Pu is an alpha emitter whose radiation is far more localized than the I-131's beta and gamma emissions. Moreover, iodine unlike PuO is soluble and absorbed into the blood stream pretty quickly. The hot particle theory, even if it were true, does not apply to this situation. The problem, if there is one, will be that absorbed iodine concentrating in the thyroid.

5718 Fukushima workers including most of the high dose cases have been closely tracked in a government funded program. As of end of 2019, no significant health effects have been observed.\cite{kitamura-2022} Kitamura et al write: "The blood test results showed that the study participants were no different from the healthy Japanese men population." These tests included thyroid function, mainly the amount of TSH (thyroid stimulating hormone).

These authors note that the group does drink and smoke more than the Japanese average. Guys who take on perceived dangerous jobs tend to do that. Down the road, they will die slightly sooner than the general population. This will be blamed on radiation.

The iodine plumes after Fukushima have received lots of attention. Tsuruta et al conclude that the iodine in the plume started out as mostly gas and then developed into aerosols. At high concentrations, it's almost all gas, dropping to around 60% gas at concentrations of around 1000 Bq/m3.\cite{tsuruta-2019}[Fig 7] The big worker doses probably were mostly gas.

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