Doses from releases to air inside

For endpoints of the type inside which are linked to scenarios with impacts of the type releases to air, SAFRAN will apply the procedure shown in Table 3.10 for assessment of doses inside the facilities.

Table 3.10. Doses inside the facility from accidental releases to air


RN – radionuclide, SDB – SAFRAN Internal Database, N/A – not applicable. The cell marked in read is used in the Analysis Module for comparison of hazards.

Definition of columns in Table 3.10:

  • Column 1. Short name of the scenario.
  • Column 2. Distance to the source.
  • Column 3. Exposure time.
  • Column 4. Dispersion factor.
  • Column 5. Short name of the radionuclides (RN).
  • Column 6. Release of each radionuclide.
  • Column 7. Protection factor.
  • Column 8. Dose from the release.

Columns in Table 3.10 that can be modified by the user: column 2 – to define the distance to the source, 3- to define the exposure time, column 4 – for entering the dispersion factor, column 7 – for entering the protection factor, column 8 - for entering directly dose values.

The doses from exposures inside the facility due to accidental radionuclide releases to air are calculated with equation 3.11, which takes into account exposures via inhalation and external irradiation from the cloud.



Releasei is the release to air inside the facility of the i-th radionuclide Bq,

DispFactor – is the dispersion factor h/m3,

InhRate is the inhalation rate of the exposed individual m3/h,

DCCiinh is the dose coefficient for internal exposure to the i-th radionuclide via inhalation Sv/Bq,

DCCiextCloud is the dose coefficient for external exposure from the cloud to the i-th radionuclide Sv/h per Bq/m3

ProtectionFactor unitless – considered in equation 1 only for inhalation – it might be necessary to introduce it also for exposure to the cloud.

The dispersion factor is defined as the concentrations in air, per unit release, at a given distance integrated over the exposure period. Values of dispersion factors for different distances and exposure times are available in the SAFRAN Internal Database. The user can also add own dispersion factor values in Table 3.10 and/or the SAFRAN Internal Database.

The protection factors have a value between zero and one and are the fractional reduction in incorporation of radionuclides via inhalation provided by protective equipment, such as respiration masks.