Derivation of Operational Intervention Levels for the early phase of radioactive material at Koeberg Nuclear Power Station
Date
2015-01-29
Authors
Trollope, Ian Douglas
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Abstract
An investigation was performed to look at a method to develop easy to use field
survey measurements to assist decision makers in the process of deriving public
protective actions. This method could be used at a nuclear power plant if certain
accident conditions are known. International values for operational intervention
levels (OIL’s) do exist and are recommended to be employed if station specific
data has not been derived. No values exist specific to Koeberg Nuclear Power
Station and as a result, this became an ideal opportunity to derive station specific
values.
It was firstly necessary to decide on a specific accident type and hence an
applicable accident release fraction. A suitable accident software dispersion code
was applied to calculate the organ doses for the selected accident type. It was also
decided to use two different wind dispersion criteria to further refine the results.
Due to the complexities of dose distribution within the body it was also necessary
to look at the gamma dose in isolation as this would be the measurement radiation
type utilised as a limit in the field either using installed radiation monitors or by
physical measurement performed by station Radiation Protection staff.
Comparisons were done with thyroid and lung dose versus gamma dose to arrive
at ratios for this specific accident type. This would then be indicative of the total
dose to each organ as a result of a single field measurement.
Conclusions were drawn on the results obtained and recommendations were made
for when this type of data may be suitable for use in the unlikely event of a
nuclear accident.
Description
A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science, Joannesburg, 2014.