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IMPACT ON PEOPLE AND THE ENVIRONMENT
Release

THE BASIS OF THE DEFINITION (1)

 

In each event the isotopes released will be different. Any isotope could have been used as the basis of the definition, but it was decided to use iodine-131 (131I) as it is typically released in reactor accidents. A methodology for relating release of any other isotope to the quantity of 131I was then defined and multiplication factors were calculated.

Am-241 H-3 Mo-99 Sr-90 U-235(F)a Unat
Co-60 I-131 P-32 Te-132 U-238(S)a Noble gases
Cs-134 Ir-192 Pu-239 U-235(S)a U-238(M)a  
Cs-137 Mn-54 Ru-106 U-235(M)a U-238(F)a  

a Lung absorption types: S - slow; M - medium; F - fast. If unsure, use the most conservative value.

The basic approach is to see how much more or what fraction of each isotope would give the same dose as a release of 131I.

All releases are assumed to be atmospheric. The calculation of dose assumed two exposure pathways. Do you know what they are?

1. click here to reveal the first pathway of exposure

1. That from inhalation.

2. click here to find out what the second pathway of exposure is

2. Long term external radiation from material deposited on the ground, integrated over 50 years.

Ingestion was not considered, as it is likely that food intervention measures would prevent any significant dose.