Development of Dual Counting Analysis and Exposure Possibility Evaluation for Carbon-14 at Korean Nuclear Power Plants

In a Pressurized Heavy Water Reactor (PHWR), most internal radiation exposure is attributed to tritium. Carbon-14 is not a dominant nuclide in the radiation exposure of workers, but it is one of the potential nuclide that needs to be monitored. Carbon-14 is a low energy beta emitter and passes relatively easily into the body of workers by inhalation because its dominant chemical form is radioactive carbon dioxide (CO2). Most inhaled carbon-14 is rapidly exhaled from the worker’s body, but a small amount of carbon-14 remains inside the body and is excreted by urine. In this study, a method for dual analyzing tritium and carbon-14 in urine samples of workers at nuclear power plants was developed. As a result of the developed dual counting analysis of tritium and carbon-14 in the urine samples of radiation workers who entered the high radiation field area at a PHWR, it was found that internal exposure to carbon-14 is unlikely to occur. In addition, through the urine counting results of radiation workers who participated in the opening process of steam generators at pressurized water reactors (PWR), it was found that the likelihood of internal exposure to either tritium or carbon-14 is extremely low at PWR.