earticle

영어

In a pressurized heavy water reactor (PHWR), radiation workers who have access to radiation controlled areas submittheir urine samples to health physicists periodically; internal radiation exposure is evaluated by the monitoring of theseurine samples. Internal radiation exposure at PHWRs accounts for approximately 20 ~ 40% of total radiation exposure;most internal radiation exposure is attributed to tritium. Carbon-14 is not a dominant nuclide in the radiation exposure ofworkers, but it is one potential nuclide to be necessarily monitored. Carbon-14 is a low energy beta emitter and passesrelatively easily into the body of workers by inhalation because its dominant chemical form is radioactive carbon dioxide(14CO2). Most inhaled carbon-14 is rapidly exhaled from the worker’s body, but a small amount of carbon-14 remainsinside the body and is excreted by urine. In this study, a method for dual analysis of tritium and carbon-14 in urine samplesof workers at nuclear power plants is developed and a method for internal dose assessment using its excretion rate resultis established. As a result of the developed dual analysis of tritium and carbon-14 in urine samples of radiation workerswho entered the high radiation field area at a PHWR, it was found that internal exposure to carbon-14 is unlikely to occur.Inaddition, through the urine counting results of radiation workers who participated in the open process of steam generators,it was found that the likelihood of internal exposure to either tritium or carbon-14 is extremely low at pressurized waterreactors (PWRs).