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Comment Re:Cute, but not accurate (Score 1) 392

Sieverts are actually the equivalent dose, which has units of energy deposited per kg of tissue (J/kg).

To calculate equivalent dose from an external radiation source, you have to take the exposure, X (C/kg or R), and calculate the absorbed dose, D, (J/kg or Gy or rad). D depends on the energy of the energy of the incident radiation, the attenuation coefficient of tissue at that given energy, and a few other factors I think. To get from absorbed dose to equivalent dose, H, (J/kg or Sv or rem), you multiply by a unitless conversion factor Q which depends on the type of radiation being absorbed. H = D*Q. For gamma rays, Q is 1. For alpha particles, which are only a risk if the alpha emitter is already in your body, the Q factor is 20.

Comment Re:Nuclear Paranoia (Not) (Score 1) 145

With respect to your comment that "low-level exposure to radiation causes a cumulative increase in cancer risk" is an assumption made by the bodies who write the rules about nuclear exposure and safety. That is based on their assumption that the body does not repair damaged DNA, ever. There is actually much more evidence to the contrary that low-level exposure to radiation reduces cancer risk. See "Radiation Hormesis".

Comment Re:Oh yeah, 3 miles of molten salt piping! (Score 1) 316

Yes, some molten salts are very corrosive. I'm working with KCl-MgCl2 eutectic, and when it has oxygen or water in it, it really starts to corrode the stainless and carbon steel that we have, so we have to keep it under an inert (argon) atmosphere to minimize corrosion. Nitrate salts, on the other hand, are actually not very corrosive compared to other molten salts that are being looked at for higher temperature purposes (like nuclear reactors or secondary heat transfer loops).

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