Dose conversion factor for accidental releases to air

The SAFRAN includes procedure for evaluation of population exposure due to accidental radionuclide releases to the atmosphere. This is performed on the basis of precalculated dose conversion factors (DCF).

Values of the DCF are calculated assuming exposure conditions similar to those that are used for calculation of the generic dose conversion factors for routine radioactive releases, cf. Generic Models for Use in Assessing the Impact of Discharges of Radioactive Substances into the Environment, Safety Report Series No. 19, IAEA, Vienna (2001), Annex I:

• Release occurs from the building at the effective height of 10 m;
• It is assumed that critical group member live at a distance of 30 m from the source in the downwind direction. The terrestrial foods are produced at a greater distance from the source: crops from a distance of 100 m and milk and meat from 800 m.

Calculated DCF consider:

• External exposure by radiation from the radioactive air plume (air submersion);
• External exposure by radiation from contaminated ground (ground radiation);
• Internal exposure by radionuclides which are inhaled with the air (inhalation);
• Internal exposure as result of consumption of radionuclide contaminated foodstuffs (ingestion).