Abstract
From January 1994, U.S. nuclear plants must develop a technically rigorous approach for determining the effective dose equivalent for their w ork forces. This dissertation explains concepts associated with effective dose equivalent and describes how to assess effective dose equivalent by using conventional personnel dosimetry measurements. A M onte Carlo computer code, MCNP, was used to calculate photon transport through a model o f the human body. Published mathematical phantoms o f the human adult male and female were used to simulate irradiation from a variety o f external radiation sources in order to calculate organ and tissue doses, as well as effective dose equivalent using weighting factors from ICRP Publication 26. The radiation sources considered were broad parallel photon beams incident on the body from 91 different angles and isotropic point sources located at 234 different locations in contact with or near the body. M onoenergetic photons o f 0.08, 0.3, and 1.0 M eV w ere considered for both sources. Personnel dosimeters were simulated on the surface o f the body and exposed to with the same sources. From these data, the influence o f dosimeter position on dosimeter response was investigated. Different algorithms for assessing effective dose equivalent from personnel dosimeter responses were proposed and evaluated. The results indicate that the current single-badge approach is satisfactory for m ost common exposure situations encountered in nuclear plants, but additional conversion factors may be used when more accurate results become desirable. For uncommon exposures involving source situated at the back o f the body or source located overhead, the current approach o f using multi-badges and assigning the highest dose is overly conservative and unnecessary expensive. F or these uncommon exposures, a new algorithm, based on two dosimeters, one on the front o f the body and another one on the back o f the body, has been shown to yield conservative assessment o f effective dose equivalent. The data presented in this dissertation have many applications in nuclear industry and can be used as a basis by national regulatory agencies and other radiation protection organizations in issuing guidances and recommendations for assessing effective dose equivalent from external photon radiations.
Xu, Xie (1994). The assessment of effective dose equivalent using personnel dosimeters. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -1552147.