Safety_Series_041_1975 - gnssn - International Atomic Energy ...

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APPEN D IX IV 75
of the type of fuel involved. Account was also taken of the potential
contribution of a further power station at Atucha, which would somewhat
change the composition.
The Derived Working Limits obtained with these models and
parameters are independent of the way in which the releases are
made from the power station, since they relate to the 'blank
organism' and its critical organs.
3. Derived Working Limits for Atucha
Figure 5 summarizes the DWL values obtained for the area
near the Atucha Nuclear Power Station, with reference to stack
releases. The values indicated refer to levels caused by operation
of the power station. The radioactive fall-out (and the natural
radiation background in the case of external exposure) make an
additional contribution to the measurements indicated, and this
had to be taken into account in analysing the monitoring results.
In the case of aqueous releases the critical radionuclides are
37Cs and 6°Co. Figure 6 gives the corresponding DWL values,
which take into account the proportion of these nuclides in the
liquid effluents.
In this case, too, the values refer to the levels resulting from
operation of the power station, in addition to those due to radioactive
fall-out.
4. Sampling and interpretation
For the sampling of material suspended in the air it is recommended
that fixed collection stations be established at five positions. This
distribution takes account of points where values are likely to be
high or the population dense. These collection stations should carry
out filtration of aerosols (samples of several thousand m ) and
collection of tritiated vapour. For 131I sampling use can be made
of carbon filters, but this sampling is not considered essential.
As regards the noble gases, it is advisable to measure these in
conjunction with other contributors to the external gamma exposure.
The optimal sampling frequency is weekly, but depending on the
capacity of the equipment other intervals are acceptable.
For measuring the external exposure it is recommended that
four integrating dosimeters (films, glasses, or preferably TLD)
should be placed 1 m above the ground at the positions mentioned