Deutsch (6.2 MB) - Nagra

NAGRA NTB 85-32 - V -
SUMMARY
The biosphere model is the final link in the chain of radionuclide transport
models used for radiation dose calculations for nuclear waste repositories.
The dispersion of radionuclides from a low and intermediate level waste
repository in the biosphere and their uptake by man through food pathways
is investigated with a compartment model. The relevant biosphere parameters
were based on the model site at Oberbauenstock and compiled as a
model data set for further use in the biosphere modelling. Nuclide concentrations
in the biosphere compartments and foodstuffs as well as annual
individual radiation doses are calculated with the computer program
BIOSPH.
The present report contains a description of the model area and of its
subdivision into 4 compartments, a compilation of the relevant parameters
and the simplifying assumptions that have been made, discussion of mathematical
modelling of nuclide transport in the biosphere and of the calculation
of the individual radiation doses, a technical description of the
computer program BIOSPH and a detailed presentation of the results from
the model calculations.
The safety calculations show that the radiation doses calculated for the
base case scenario with realistic/conservative parameter values are negligible.
Even for an accumulation of several conservative assumptions, one
calculates doses that are clearly under the protection standard of 10 mrem
per year.