Dose Comparisons for a Site-specific Representative Person Using the Age-dependent Dose Coefficients in CAP88-PC Version 4
Most U.S. Department of Energy (DOE) facilities with radiological airborne releases use the U.S. Environmental Protection Agency’s (EPA) environmental dosimetry code CAP88‐PC to demonstrate compliance with regulations in 40CFR61, subpart H [National Emission Standards for Hazardous Air Pollutants: Radiological (NESHAP)]. In 2015, EPA released Version 4 of CAP88‐PC, which included significant modifications that improved usability and age-dependent dose coefficients and usage factors for six age groups (infant, 1 y, 5 y, 10 y, 15 y, and adult). However, EPA has not yet provided specific guidance on how to use these age-dependent factors. For demonstrating compliance with DOE public dose regulations, the Savannah River Site (SRS) recently changed from using the maximally exposed individual (MEI) concept (adult male) to the representative person concept (age- and gender-averaged reference person). In this study, dose comparisons are provided between the MEI and a SRS-specific representative person using the age-specific dose coefficients and usage factors in CAP88‐PC V.4. Dose comparisons also are provided for each of the six age groups using five radionuclides of interest at SRS (tritium oxide, 137Cs, 90Sr, 239Pu, and 129I). In general, the total effective dose increases about 11% for the representative person as compared to the current NESHAP MEI because of the inclusion of the more radiosensitive age groups.