Earticle

During the maintenance period at Korean nuclear power plants, internal exposure of radiation workers occurred by theinhalation of 131I released to the reactor building when primary system opened. The internal radioactivity of radiation workers contaminatedby 131I was measured using a whole body counter. Intake estimation and the calculation of committed effective dose were also conductedconforming to the guidance of internal dose assessments from publications of International Commission on Radiological Protection.Because the uptake and excretion of 131I in a body occur quickly and 131I is accumulated in the thyroid gland, the estimated intakes showeddifferences depending on the counting time after intake. In addition, since ICRP publications do not provide the intake retention fraction(IRF) for whole body of 131I, the IRF for thyroid was substitutionally used to calculate the intake and subsequently this caused moreerror in intake estimation. Thus, intake estimation and the calculation of committed effective dose were conducted by manual calculation.In this study, the IRF for whole body was also calculated newly and was verified. During this process, the estimated intake and committedeffective dose were reviewed and compared using several computer codes for internal dosimetry.