• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.223-230
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• 2015

The objective of this study is to identify the radionuclide distribution in public water by carrying out the analysis of artificial radionuclides($^{134}Cs$, $^{137}Cs$, $^{239+240}Pu$), natural radionuclide($^{210}Pb$) and TOC in the lake Euiam sediment in Chuncheon, South Korea. The $^{134}Cs$ concentration in all lake sediments showed below MDA values, and the $^{137}Cs$ concentration in lake sediment were ranged from MDA to $8.79Bq{\cdot}kg^{-1}-dry$. The $^{137}Cs$ concentrations in surface sediment were reported to be 2.4 to $4.2Bq{\cdot}kg^{-1}-dry$. The lowest concentration of $^{137}Cs$ was reported at St. 4 and the highest concentration was reported at St. 3, respectively. The $^{239+240}Pu$ concentration in lake sediment were ranged from 0.049 to $0.47Bq{\cdot}kg^{-1}-dry$. The lowest concentration was reported at St. 2 and the highest concentration was reported at St. 3. The correlation(r) between the $^{239+240}Pu$ concentration and $^{137}Cs$ concentration in lake sediment presented higher values (0.54 to 0.97) and this suggests the behavior and origin of $^{137}Cs$ is identical to the $^{239+240}Pu$ in the sediment. The $^{134}Cs$ concentration below MDA value and the $^{239+240}Pu/^{137}Cs$ ratio(mean value of 0.041) indicated that the artificial radionuclides in the sediment were originated from global fallout by the atmospheric testing of nuclear weapons conducted by former USSR and U.S.A, but not from the Fukushima Daiichi NPP accident. The sedimentation rate derived from $^{210}Pb$ age-dating method at St. 2 is calculated to be $0.31{\pm}0.06cm{\cdot}y^{-1}$. This value is similar to the value ($0.41{\pm}0.05cm{\cdot}y^{-1}$) estimated from the $^{137}Cs$ maximum peak produced from early 1960's. The content of TOC in lake Euiam sediments varied from 0.20 to 13.01%. While the highest correlation between TOC and $^{137}Cs$ concentration in the sediment were found at St. 1, the others presented the low correlation.

• Journal of Radiation Protection and Research
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• v.24 no.3
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• pp.155-160
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• 1999

In the natural, there exist several kinds of radioactive isotopes. From atmospheric weapon tests and then some isotopes are naturally radioactivity above all things, nuclear power plant operation and man-made radioactive isotopes concern steadily growing in the environment. During the fission process of nuclear weapon tests and nuclear power plant operation, more than 200 radioactive isotopes are generated. Among them, $^{90}Sr$ and $^{137}Cs$ has been regarded as very important isotopes due to characteristics. In this paper, a quantitative analysis method of environment low level $^{90}Sr$ is studied. Radioactivity level of the environmental $^{90}Sr$ is very low, and it emits continuous beta spectrum, and $^{90}Sr$ exists together with $^{89}Sr$, $^{90}Y$ and other radioactive isotopes. It very difficult to make the quantitative analysis of $^{90}Sr$. For the analysis of low level radioactive strontium, enrich and chemical separation of strontium from the other radioactive isotopes are needed. For the estimation of strontium recovery ratio, so called SGAT(Strontium Gravimetric Analysis Technique) was generally used among the domestic research groups, and chemical procedures were developed appropriation for the SGAT, Recently, by using ICP(Inductively Coupled atomic Plasma emission spectrophotometer), amounts of stable atoms can be measured easily and accurately to the extend of ppm or ppb. In this paper, new chemical procedures are developed to exploits the ICP technique. New developed method has simpler chemical treatment procedures and then it gives more accurate results compared with the traditional SGAT.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.161-166
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• 2005

In KAERI, about 3,100 drums containing soil have been stored. The soils were generated from the decommissioning process of Seoul office in 1988. Those soils occupy about $27\%$ of the capacity of the radioactive waste storage facility and make it difficult to maintain the storage facility. The major radioactive nuclides contained in the soils were expected to be Co-60 and Cs-137. As 16 years have passed, the radioactivity of those nuclides have decayed a lot. In this study, as a basis of regulatory clearance, radionuclides and radioactivity concentration of soils were analyzed. As a result, there are only Co-60 and Cs-137 in soils as ${\gamma}-emitters$. The total concentration of ${\gamma}-emitters$ in soil is analyzed as about $0.01\;{\sim}\;0.12$ Bq/g. As the soils are expected to be regulatory cleared in 2009, those concentrations will decay to be less than 0.1 Bq/g. This concentration can be meet the regulatory criteria suggested by IAEA. The regulatory clearance will be proceeded based on not only the assessment results of environmental influence but also related regulations.

• Journal of Radiation Protection and Research
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• v.31 no.3
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• pp.141-148
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• 2006

Surveys of radioactive contamination were performed for imported foodstuffs in 2003. The following samples among imported foodstuffs were selected from markets and Korea Food and Drug Administration(KFDA); the imported samples from country associated with the Chernobyl nuclear accident, the samples produced around the nuclear power plants or nuclear tests, the foodstuffs reported as radioacitive contamination materials in foreign country. After pretreatments such as drying and homogenization, samples were analyzed. The $^{137}Cs$ radionuclide was only measured among the regulation radionuclides($^{137}Cs,\;^{134}Cs,\;^{131}I$) of food code. All foodstuffs except Inonotus Obliquus(Chaga mushooms) are less than 17.0 Bq/kg or below the minimum detectable activity(MDA). The activity concentrations of Chaga mushrooms from Russia ranged up to 131.25 Bq/ltg which is almost 35 % of the maximum permitted level of food code. The fraction of imported foodstuffs having meaningful radioactivity is small, however, the radioactive contamination survey of imported foodstuffs is still needed.

• Nuclear Engineering and Technology
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• v.8 no.2
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• pp.69-76
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• 1976

This experiment has been carried out for the removal of long-lived radioactive-nuclides (Sr-90, Ru-106, Cs-137 and Ce-144) contained in the low-level radioactive effluents from the spent fuel reprocessing plant and nuclear power plant, in order to determine the decontaminability of various chemical coagulants and domestic clay mineral (montmorillonite). Phosphate process showed prominent efficiency for the removal of Ce-144, and lime-soda process did good removal efficiency for Sr-90. About Cs-137 copper-ferrocyanide process is much desirable. In phosphate or lime-soda process, most favorable removal efficiency was obtained at more than pH 11. The montmorillonite treated with sodium chloride showed a considerable improvement in the removal of the radioactive-nuclides. By a combined chemicals-montmorillionite process, the radioactive-nuclides could be more effectively removed than by the only chemicals process.

• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.24-29
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• 1983

The effects of temperature on the uptake of $^{137}Cs$ from seawater and on the retention after its uptake by the clam Cycling sinensis was investigated under laboratory conditions. The clams exhibited a greater bioaccumulation of $^{137}Cs$ in $25^{\circ}C$-acclimated animals than those acclimated at $15^{\circ}C$. The viscera of the clams reached the highest bioconcentration factor after 14 days uptake from seawater, but the tissue distribution pattern of $^{137}Cs$ was little influenced, if any, by the uptake temperature. The uptake rate slightly decreased with an increase of temperature in order of $10^{\circ}C$. The radionuclide accumulated in clams was released again in a radionuclide-free seawater according to a two-exponential compartment model. A temperature increase of $10^{\circ}C$ reduced the biological half-life of the long-lived component with a factor of about two, whereas it caused no change in the short-lived component.

• Journal of the Korean Society of Radiology
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• v.5 no.1
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• pp.5-10
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• 2011

Based on basic concept of detection limit, sample measurement time & background measurement time was considered, and MDA values according to background measurement time and sample measurement time in land samples(river soil, surface soil, drinking water, underground water, surface water, pine leaf, mugwort) analysis among environmental samples were compared. Seeing the water sample analysis result, it was shown that most of the samples were not detected, and most of the samples in land specimen analysis showed to be below the detection limit of "Ministry of Education, Science and Technology Announcement Je-2008-28-ho", but $^{137}Cs$ which is one of artificial radioactive nuclide was detected in some samples. It can be traced back to 1950s and 1960s when nuclear tests were carried out in atmosphere and catastrophic Chernobyl atomic power station accident that caused fallouts in the sky, and this is common level of detection that can be observed worldwide. Seeing the result that the $^{134}Cs$(which is a isotope of $^{137}Cs$, and it has relatively short half life) was not detected in all samples, it can be considered it doesn't affect to the operation of atomic power station.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.1
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• pp.57-61
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• 2016

The Tomographic Gamma Scan (TGS) technique partitions radioactive waste drums into $10{\times}10{\times}16$ voxels and assays both the density and concentration of radioactivity for each voxel thus providing for improved accuracy, when compared to the traditional Non-Destructive Assay(NDA) techniques. It could decrease the degree of precision measurement since there is a trade-off between spatial resolution and precision. This latter drawback is compensated by expanding the Region of Interest (ROI) that differentiates the full energy peaks, which, in turn, results in an optimized degree of precision. The enlarged ROI, however, increases the probability of interference among those nuclides that emit energies in the adjacent spectrum. This study has identified the cause of such interference for the reference nuclide of the TGS technique, $^{137}Cs$ (661.66 keV, half-life 30.5 years), to be $^{110m}Ag$ (657.75 keV, half-life 249.76 days). A new calibration method of determining the optimized ROI was developed, and its effectiveness in accurately characterizing $^{137}Cs$ and eliminating the interference was further ascertained.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.544-548
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• 2003

The Irradiation test of bar code label tagged on radioactive waste container was done to determine the effect of radiation. Low and medium radioactive waste is that below total activity of 4,000 Bq/g according to the Korean nuclear law. The irradiation amount to radiate bar code label tagged on radioactive waste container was calculated by MCNP-4b computer code. The nuclide such as Co-60 and Cs-137 was assumed to contribute 50% of total activity. Real irradiation amount for bar code label was finally calculated by the dimensions of the container and the bar code label. The Identification of post and the physical deflection of irradiated bar code label was tested by the bar code reader. The coated bar code label was suitable to use on low and medium radioactive waste container.

• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.31-36
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• 2020

To ensure food safety of berries from radioactive contamination, radioactivity monitoring was conducted with a total 258 samples of the berries and processed berry products distributed in Gyeonggi-do, South Korea, from 2016 to 2018. The concentration of artificial radionuclides, ¹³¹I, ¹³⁴Cs and ¹³⁷Cs, was analyzed using gamma-ray spectrometry. ¹³¹I and ¹³⁴Cs were not detected above the MDA (Minimum Detectable Activity) value from any of the samples. However, the range of radioactivity concentration of ¹³⁷Cs was 0.69-808.90 Bq/kg in 39 cases of berries. ¹³⁷Cs was detected at 0.70-3.29 Bq/kg from 6 cases of domestic berries, which were manufactured from imported raw materials. Among 33 cases of imported berries, ¹³⁷Cs was detected at 0.69-808.90 Bq/kg. The concentrations of ¹³⁷Cs in 1 case of blueberry powder product (808.90 Bq/kg) and 2 cases of lingonberry powder products (103.93, 188.46 Bq/kg) exceed domestic maximum radioactivity limits, and these were detected in the berries from Poland. These results suggest that monitoring system for imported berries and processed berry products should be continuously intensified to secure food safety.