A8.2 Determination of Proportionality Constant Fi

The proportionality constant Fi for radionuclide i was determined from the following relationship:

where: Cx is the annual water consumption for age group x (l /a)

(DCF)ix is the dose conversion factor for radionuclide i and age group x (mSv/Bq)

Wx is the weighting factor for age group x

The annual water consumption values for the various age groups were taken from CNS Licensing Guide LG-1032, and are given in Table A8.3.

Table A8.3 Annual Water Consumption Values

Age Group

Water Consumption (l /a)

0 - 1 years

200

1 - 2 years

260

2 - 7 years

300

7 – 12 years

350

12 - 17 years

600

> 17 years

730

The dose conversion factors for the various radionuclides and age groups were taken from the IAEA Basic Safety Standards.

The weighting factor for each age group was determined by dividing the number of years in the age group by the average life expectancy, taken to be 70 years. For example, the weighting factor for the 7 - 12 years age group was:

and for the > 17 years age group:

The resulting proportionality factors for each radionuclide are listed in Appendix 2 as the ‘annual dose per unit activity concentration in water’.