Dose coefficients for external exposure from the cloud

As default, SAFRAN performed dose calculations for releases inside incorporate the US Environmental Protection Agency Federal Guidance Report No. 12 provided values of effective dose per time integrated activity concentration in the air esub (Sv per Bq s m-3). The publication provides values for effective equivalent dose and equivalent skin dose separately. The effective dose factor is calculated as follows:

esub = hE + 0.01 hT

Where: hE – is the effective equivalent dose factor for air submersion (dose to skin is not included into summation); hT – is the skin equivalent dose factor for air submersion.

The publication provided dose factors do not include consideration of radiations emitted by radioactive decay products. Following the approach used in the IAEA Safety Report Series No. 19, esub values for some of radionuclides are additionally upgraded to account for impact arising from their progenies. These radionuclides and considered progenies are listed below:

Bi-212Tl-208 (0.3593), Po-212 (0.6407)
Ce-144Pr-144 (0.9857)
Cs-137Ba-137m (0.9457)
Mo-99Tc-99m (0.8860), Tc-99
Te-131mTe-131 (0.2220), I-131 (0.7780)

Where relevant, progeny branching ratios are shown in brackets