• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.

• Journal of the Korean Geophysical Society
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• v.7 no.1
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• pp.61-72
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• 2004

In this project, under the server-client environment, GIS for the radiological emergency and control system of the vehicles for the environmental radioactivity monitoring was complete. This system is able to display environmental radioactivity data and vehicle's locations through wireless network on real time. Furthermore, it supports not only static analysis function with the collected data regarding nuclear type, collecting time period and vehicle's location but also a documents printing out function.

• Journal of Sensor Science and Technology
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• v.26 no.6
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• pp.427-431
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• 2017

In this study, a foods radioactivity monitoring sensor was developed as a part of basic research for household radioactivity monitoring, and its performance was evaluated using a calibration source. The prototype of the sensor was based on a CsI:Tl scintillator using a crystal light guide and Si photomultiplier. The light guide was introduced to improve gamma-ray detection efficiency. For quantitative evaluation, tests were conducted using $^{134}Cs$ liquid source. In the performance evaluation, It was confirmed that analysis of $^{134}Cs$: 100 Bq/L(kg) was possible. Thus, result of this study is expected to contribute to research in the development of the household foods radioactivity monitoring system.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.770-780
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• 2022

In 1993 the University of Extremadura initiated the design, construction and management of the Radiological Alert Network of Extremadura (RAREx). The goal was to acquire reliable near-real-time information on the environmental radiological status in the surroundings of the Almaraz Nuclear Power Plant by measuring, mainly, the ambient dose equivalent. However, the phased development of this network has been carried out from two points of view. Firstly, there has been an increase in the number of stations comprising the network. Secondly, there has been an increase in the number of monitored parameters. As a consequence of the growth of RAREx network, large data volumes are daily generated. To face this big data paradigm, software applications have been developed and implemented in order to maintain the indispensable real-time and efficient performance of the alert network. In this paper, the description of the current status of RAREx network after 30 years of design and performance is showed. Also, the performance of the graphing software for daily assessment of the registered parameters and the automatic on real time warning notification system, which aid with the decision making process and analysis of values of possible radiological and non-radiological alterations, is briefly described in this paper.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.186-191
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• 2007

The objective of this research was to assess the reliability of data and to improve nuclear analytical techniques concerning the Domestic Radioactivity Intercomparison program for environmental radioactivity monitoring of Jeju from 1998 to 2006. Gross beta for filter papers and water samples was determined, and gamma nuclides for natural and artificial nuclides in soil and water samples were analyzed. The gross beta activity of all samples except for the water samples of 1998 and 1999 showed a good agreement within the confidence intervals. In gamma nuclides, $^{40}K$ and $^{137}Cs$ of soil samples and most nuclides in the water samples, with the exception of several nuclides, were evaluated to be reliable. Based on these results, it is considered that a reliable method for the analysis and monitoring of environmental radioactivity were established, which may play an important role in case of emergency radiation accident.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.459-461
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• 2022

In this paper, we propose a measurement system for measuring radioactivity detected in an indoor environment. This is to measure and prevent radiation generated in various spaces such as general house, workplace, and research institutes. Multi-radioactivity sensors are used to measure multiple spaces simultaneously. The measured radioactivity data is transmitted to the PC in real time through ZigBee and monitored. Even with a small amount of radioactivity, it is considered that it must be installed in a place where radiation exposure is expected, such as a laboratory or workplace, for prevention from chronic radiation syndrome.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.3
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• pp.55-62
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• 2013

Generally, the radioactivity from NPP(Nuclear Power Plants) operation can be released below 3% of DRLs(Derived Release Limits) to environment. It was tried to understand which plant was efficient for absorbing radioactivity in this study. Pinus thunbergii Parl. and Viburnum awabuki K. KOCH were analyzed for radioisotope absorption. The samples were collected at three different locations depending on the distance from NPP at the vicinity 10km away, and 30km away. Gamma radionuclide was not detected from the samples, which means that the direct transition into the plant was not significant. Meanwhile, the very low level of radioactive tritium was detected in the samples. One remark was that every plant has different ability for tritium absorption. These results are expected to be applied to propagation and transplanting in radioactively contaminated area or reducing radioactivity in the soil and water near the plants.

• Journal of Radiation Protection and Research
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• v.23 no.2
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• pp.65-74
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• 1998

One of the important things in low level radioactivity measurement is determination of the optimized counting time. Counting strategy has to be established, in order to count the radioactivity of the sample by condition of optimized measurement. There were three kinds of counting strategies in this report ; about fixed time, about fixed count, to compared sample, background, and reference level. The best of them was satisfied rendition to give about condition of instrument and process, as an example, efficiency of detector, counter capacity, maximum and average background count rate of counter, reference level and limit of derision and detection, etc. Therefore, we can decide the optimized counting time in the screening and monitoring. And we can save the time for courting the sample of course the data of count will be counted by optimized accuracy finally, in rountine measurement of radioactivity these strategies will be used available.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4554-4560
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• 2023

Continuous monitoring of radioactive substances over a prolonged duration can yield crucial insights into the levels of radiation exposure through inhalation, both in the vicinity of nuclear facilities and/or general environments. In this study, we evaluated long-term measurements (2012-2022) of gross alpha-beta activities in the air in the vicinity of nuclear facilities and reference site, distribution characteristics of temporal trends and spatial fluctuations, and factors affecting radioactivity levels. The average airborne gross-α (in mBq m^-3) for onsite and off-site were 0.124 and 0.117, respectively, and the average airborne gross-β (in mBq m^-3) measurements were 1.10 and 1.04, respectively. The activity ratio (AR) of gross-α and gross-β were calculated as a ratio of 0.12. The distribution characteristics of gross-α and gross-β activities in this study area are likely influenced by the meteorological factors and variations in airborne PM concentrations rather than the operation of the nuclear facility.

• Analytical Science and Technology
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• v.31 no.3
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• pp.134-142
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• 2018

The uranium isotopic ratio in environmental samples around nuclear facilities is important because it reveals information regarding illegal activities or anthropogenic pollution. Determination of uranium isotopes, however, is a challenging task requiring much labor and time because of the complex separation procedures and lengthy process. In this study, a rapid determination method for uranium isotopes in environmental samples was developed using. The sample was completely decomposed using the alkali fusion method. The separation procedure using extraction chromatography (UTEVA) was simplified in a single step without any further removal process for Si and major matrix elements. The established method can be completed within 3 h from sample dissolution to ICP-MS measurement. Most matrix elements and uranium isotopes in the soil samples were well separated and purified. Five types of were used to assess the method's accuracy and precision for a rapid uranium analysis method. The analytical accuracy for all CRM samples ranged from 95.1 % to 97.8 %, and the relative standard deviation was below 3.9 %. From the analytical results, one may draw conclusions that the evaluated method for uranium isotopes using alkali-fusion, the extraction chromatography process, and ICP-MS measurements is fast and fairly reliable owing to its recovering efficiencies. Thus, it is expected that the evaluated method can contribute to the improvement of environmental monitoring ability.