Safety_Series_041_1975 - gnssn - International Atomic Energy ...

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AN N E X III
DOSE E STIM A T E S
IN TR O D U C TIO N [15]
The estimation of the dose received by the population is based
on the estimation of any dose received from external radiation and
of the concentration of individual radionuclides in ingestion and
inhalation pathways and the use of mathematical models to relate
these concentrations to organ or whole-body doses. The estimated
dose from inhaled or ingested radionuclides is then added to the
measured or calculated dose from exposure to external radiation to
give the total dose.
Even with the most sensitive radiation detectors it is som etim es
difficult to make measurements of the external radiation or the
concentrations of radionuclides in environmental media that are
attributable to discharges from a nuclear installation under normal
operating conditions. The population doses are therefore m ore
usually estimated from the known activities of radionuclides
discharged and the postulated critical environmental pathways and
reconcentration factors. W herever possible, such estimates should
be compared with calculations based on environmental monitoring
results. In some cases, however, the calculations based on
measurements will only show that the population dose is less than
some level representing the detection lim it of the measuring system.
The models used for calculating the concentrations of radionuclides
in the environment should be representative of the environmental
and demographic characteristics of the area. The
environmental characteristics include those relating to m eteorology,
hydrology and pathways for exposure to external radiation and to
internal exposure from inhalation and ingestion of water and food.
The demographic characteristics include population distribution and
eating, recreational and other appropriate habits. It may be possible
to identify a hypothetical person who receives the maximum dose.
This might be a person who lives at the area of maximum predicted
ground-level concentration, or a person who eats food grown in the
area of highest concentration or ingests or is otherwise exposed to
contamination in an identified critical pathway.
The demographic data should also permit the identification of
the critical population group. The location of the critical group may
be far from the responsible installation.
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