Feasibility of miniature radiation portal monitor for measurement of radioactivity contamination in flowing water in pipe

Abstract

In this study, a miniature radiation portal monitor and an operation program were developed and tested for monitoring radioactive contamination of water caused by nuclear power plant accidents or unplanned release of radioactive materials. In order to set the optimum voltage of the detector, the voltage was increased by 1 V and the detection efficiency was measured. It was confirmed that the detector had a stable count and a high signal-to-noise ratio at 60 V. The detector response, gamma-ray energy spectrum, and energy linearity were tested using the detector with an applied voltage of 60 V. The R-square value of the detector response based on the intensity was 0.9980 and the R-square value of the channel linearity based on the energy was 0.9851, which indicates the detection characteristics to be very good. In addition, the system showed good resolution characteristics in which the gamma-ray emission energy 122 keV of the 57Co had an energy resolution of 16.02%, 662 keV of the 137Cs spectrum had 4.88%, and 1,332 keV of the 60Co had 2.02%. Based on the results from this study, it is determined that continuous research work may contribute in reducing the radioactive exposure caused by contamination of groundwater and drinking water in radioactive spill accidents.