Extension of NCRP 129 to short-lived radionuclides.

Abstract

NCRP 129 contains dose conversion factors for 200 radionuclides that allow one to estimate the maximum dose to an individual based on the concentration of the radionuclide in the soil and the way in which the land is used. The methodology of NCRP 129 has been extended to be applicable to 28 common short-lived radionuclides and their progeny, and dose conversion factors were obtained for these radionuclides. In addition to applying the NCRP 129 calculational methodology to these radionuclides, holdup times from harvest or slaughter until consumption have been incorporated into the decay correction equations used to determine the maximum annual dose due to the significance of the holdup time with respect to the dose from short-lived radionuclides. These holdup times were included in the Monte Carlo sampling regimen used in NCRP 129. A test using emission rates proportional to those of the Chernobyl event indicated that areas of high dose, where rainout occurs, more than doubled in areas where short-lived radionuclides from this study were included.