Optimization of Monitoring System using Plastic Scintillator for Beta nuclide including Tritium in Water

Department of Nuclear EngineeringVarious radionuclides can be generated from decommissioning sites and nuclear facilities. Radionuclides can move through water, so monitoring is essential. A monitoring system has been established to detect beta-nuclides in water samples around nuclear facilities. Beta-nuclides, including tritium, have a short range and difficulty in detecting in water samples. In order to solve this problem, the detection chamber of the structure in which the scintillator and the water sample directly contact is designed and constructed. The system is constructed using a plastic scintillator that does not react with water and has a low background level because of its low atomic number. In order to increase detection efficiency, the area of reaction between the water sample and the scintillator is increased by using the multi-layer scintillators structure. Thirteen scintillators are used for low energy beta, such as 3H, and seven scintillators were used for the relatively high energy 90Sr. Using the manufactured detection chamber, an electronics of monitoring system for each nuclide is set. The change of the detection efficiency is confirmed by changing the amplification degree of the main amplifier. The amplification degree of the main amplifier is selected for each case of 3H and 90Sr. The major beta nuclides, 90Sr and 3H nuclides are considered, and the performance of the system is evaluated by the time required to derive the MDA to satisfy regulatory standards for each nuclide. The liquid radioactive effluent level is used for 90Sr and 3H. In case of 90Sr, it takes 18 seconds to satisfy 0.02 Bq/g of effluent level. In the case of 3H, it takes 2,300 seconds to satisfy the standard for effluent level of 40 Bq/g. It is considered that scintillation-based radiation monitoring systems for beta nuclide in water can be used to evaluate effluent level for 3H and 90Sr. The system is expected to be used to ensure the radiological safety of the operating nuclear facilities and decommissioning sites of nuclear power plants.clos

Development of AN On-site, Rapid, Environmental Radiation-distribution Monitoring System for Decision Making during a Radiation Emergency

An on-site, rapid, measurement-based, radiation-distribution visualization system with radionuclide recognition was developed for quick decision making during a radiation emergency. After scanning of the area was complete, radionuclide-specific radiation-distribution contours were displayed in two and three dimensions on a map of the measurement area, in a few tens of seconds, by clicking once on an execution file, which was programmed using MathWorks' MATLAB software. The contours were fundamentally verified using Cs-137 and Co-60 standard sources. Radiation distribution in the measurement area was simultaneously displayed in the main office using code division multiple access. It was demonstrated that rapid decision making for public safety is possible through the prompt display of radiation distribution in a nuclear emergency environment. This can also be applied to establish an environmental restoration plan for decontamination and decommissioning of nuclear power plants

The Application of the Portable Nuclide Recognizing Rapid Radiation Distribution Monitoring System for Ensuring Radiation Safety

The portable nuclide recognizing rapid radiation distribution monitoring system was developed for the in-situ detection of contamination in the field and quick grasp of the distribution of radiation levels at radiation emergency. The system was composed of a combination of the hardware (portable detector, GPS) and the software (digital map and program for the quick data treatment). Also, simultaneous display system was constructed by CDMA remote data communication method. The five sites of non-destructive testing industries were scanned for filed application. The distribution of dose rate was from 0.071 to 0.112??Sv/hshowing that it fell on the environmental radiation level of Korea. It was demonstrated that the developed system with quick display of radiation distribution could be used to easily find relative hot spot and to secure the quick measure for the public radiation safety

Analysis of the Influence of Nuclear Facilities on Environmental Radiation by Monitoring the Highest Nuclear Power Plant Density Region

Monitoring of environmental radioactivity is essential for ensuring the radiological safety of residents who live near nuclear power plants. Ulsan, South Korea, is surrounded by 16 nuclear power plants, the highest density in the country. In addition, the city contains facilities for conducting radiological nondestructive testing and using radioisotopes for medical purposes. It makes the confirmation of radiological safety particularly necessary. In this study, sampling points were selected based on regional characteristics, and surface water samples were pretreated and analyzed for gross beta and gamma radiation levels. In addition, the distribution of the city???s gamma dose rate was determined using a mobile monitoring system and distribution visualization program. The results showed that there is no effect on the gross beta and gamma nuclides of artificial radionuclides, and the gamma dose rate of the entire region did not exceed the environmental radiation level in South Korea overall, confirming the radiological safety of the city