Determination of the Maximum Permissible Activity of 60Co Line Source for Different Application Modes of Lead Cell

Isolation of radiation sources is one of the most important methods of the radiation protection in order to prevent harm to human beings. Usually, lead cells with plumbic brick walls are used for isolation of medium and low radiation level sources. In this research, the maximum permissible activity of 60Co line source was calculated using both the analytical and Monte Carlo methods, such that the handling of this amount of activity inside the lead cell with 5 cm standard plumbic brick walls, could fulfill the accepted international criteria for lead cells application in restricted areas. The difference between the analytical and Monte Carlo results was obtained less than 16% in average. The results showed that, the activity of 60Co source should be less than 5.61 and 48.25 mCi for the analytical method and less than 6.67 and 56.36 mCi for Monte Carlo method respectively at irradiate/storage and load/unload (as well as transient) operation modes. The proposed analytical method could generate MCNPX code data with relatively good approximation.