Effective dose equivalent due to gamma-ray emissions from hot particles

The quantification of dose from hot particles in the nuclear power industry has received a good deal of attention in the past few years. Specifically, calculational models have been developed to determine shallow dose equivalent from both beta and gamma-rays (using VARSKIN) and to estimate deep dose equivalent based upon the gamma dose at a tissue depth of 1 cm, These two values are reported for regulatory purposes. The purpose of this study is to estimate another measure of dose from hot particles (or from skin contamination over a small area), specifically the effective dose equivalent which takes into account all organs of the body receiving appreciable dose from the gamma-ray emissions from the contamination, While it is generally recognized that this dose will be small, this study gives representative doses for a range of hot particle locations and gamma-ray energies. MCNP and the ADAM phantom have been used for the calculational model. The effective dose equivalent is found to range from 0.1 to 12 mu Sv h(-1) MBq(-1) (0.4 to 43 mu rems h(-1) mu Ci(-1)) of gamma activity, depending upon the location of the hot particle on the body.