Is There a Need for Reducing the Limit on Surface Dose Rates of Packages During Transport of Radioactive Material?

Abstract

AbstractNearly 25,000 packages containing radioactive material are annually transported in India. The three isotopes which contribute maximum dose to the transport workers are 131I, 192Ir and 99Mo. These packages have been analysed with respect to surface dose rate, activity content and weight in order to assess whether the surface dose rate has to be reduced in the light of the revised dose limits recommended by the ICRP. It is observed that there exists an inverse relationship between the weight of the package and surface dose rate, thus rendering the heavier ones less important from the point of view of dose to the handlers. The analysis shows that none of the packages containing 131I or 192Ir had surface dose rates approaching the permitted limit of 2 mSv.h−1 and in the case of 99Moonly 1.34% of the packages were in that category. In all cases the distribution was skewed towards lower dose rates. Hence, a notional reduction in the limit for surface dose rate may not have any impact on the dose receive...