• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.71-79
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• 2016

Background: It is necessary to analyze radioactivity of naturally occurring radioactive materials (NORM) in products to ensure radiological safety required by Natural Radiation Safety Management Act. The pretreatments for the existing analysis methods require high technology and time. Such destructive pretreatments including grinding and dissolution of samples make impossible to reuse products. We developed a rapid and simple procedure of radioactivity analysis for thorium series in the products containing NORM. Materials and Methods: The developed method requires non-destructive or minimized pretreatment. Radioactivity of the product without pretreatment is initially measured using gamma spectroscopy and then the measured radioactivity is adjusted by considering material composition, mass density, and geometrical shape of the product. The radioactivity adjustment can be made using scaling factors, which is derived by radiation transport Monte Carlo simulation. Necklace, bracelet, male health care product, and tile for health mat were selected as representative products for this study. The products are commonly used by the public and directly contacted with human body and thus resulting in high radiation exposure to the user. Results and Discussion: The scaling factors were derived using MCNPX code and the values ranged from 0.31 to 0.47. If radioactivity of the products is measured without pretreatment, the thorium series may be overestimated by up to 2.8 times. If scaling factors are applied, the difference in radioactivity estimates are reduced to 3-24%. Conclusion : The developed procedure in this study can be used for other products with various materials and shapes and thus ensuring radiological safety.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1275-1276
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• 2004

• Analytical Science and Technology
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• v.13 no.6
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• pp.693-698
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• 2000

The object of this series of experiments was aimed for the systematic and long-term radioactivity monitoring through indirect search of C-14 concentration level changes in the natural conditions around the operating nuclear facilities. The result of environmental radioactivity level through tree-ring analysis is increased after operating nuclear facilities and such a level can be proved to relate power generation closely. The measured result of ${\delta}^{13}C$ through the treatment of cellulose can be showed the level -30‰. This figure is very different from one which is measured the -17‰ of air sample by passive air sampling and -8‰ of air sample by active air sampling. And these differences can be assumed as isotope fractionation by photosynthesis, but the problem is more study as needed.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1638-1649
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• 2019

Top soil samples across the state of Kuwait numering ninety were collected and analysed using gamma-ray spectrometry, to evaluate the elemental concentration of $^{238}U$, $^{232}Th$ and $^{40}K$ and their depletion/enrichment. Results of elemental concentration ranges from 0.48 to 2.61 mg/kg, 0.87-5.23 mg/kg, and 0.24-2.23%, with a mean values of 1.39 mg/kg, 3.47 mg/kg, and 1.18%, for the $^{238}U$, $^{232}Th$ and $^{40}K$, respectively. Further analysis was conducted amongst the five identified soil types, i.e. Aquisalids (S1), Calcigypsids (S2), Petrocalcids (S3), Petrogypsids (S4), and torripsamment (S5). The highest radioactivity concentrations from both uranium and thorium were recorded in the S2 (Calcigypsids) soil, with a value of 1.71 (mg/kg) and 4.45 (mg/kg), respectively. Minimum and maximum values of $^{40}K$ are 1.1(%) and 1.27(%) and is prevalent in Aquisalids (S1) and Petrocalcids (S3) soil types, respectively. Ratios of elemental concentration for $^{232}Th/^{238}U$, $^{40}K/^{238}U$, $^{40}K/^{232}Th$ across the soil types are 2.53, 0.09 and 0.03, with a correlation coefficient of 0.92, 0.34, and 0.38, respectively. A progressively higher $^{232}Th/^{238}U$ ratio is observed moving south-wards, indicating lower $^{238}U$ content in soils from the south relative to the northern part. Overall results indicate Kuwait to be relatively an area with low level of natural radioactivity.

• Analytical Science and Technology
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• v.30 no.5
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• pp.262-269
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• 2017

The concentration of natural radioactivity in the sediment of the Geum River was investigated. The river and lake sediment samples were collected at 23 points during September to November, 2015 and March to April, 2015, respectively. The gamma-rays emitted from the $^{226}Ra$ and $^{232}Th$ decay series and $^{40}K$ were measured with a high purity germanium (HPGe) gamma detector. The average radioactivity concentrations of the $^{226}Ra$, $^{232}Th$ decay series and $^{40}K$ for the river sediment was found to be $15.6{\pm}0.6$, $33.8{\pm}1.2$, $789.8{\pm}26.0Bq/kg$, respectively, while for the lake sediment, the concentrations were $17.1{\pm}0.5$, $37.8{\pm}1.1$, $269.4{\pm}9.6Bq/kg$, respectively. Spearman's correlation was conducted to compare the radioactivity concentration and properties of the sediment. The radioactivity concentration of the $^{232}Th$ decay series showed a negative correlation with the particle size of the sediment, and was measured to be higher than the $^{226}Ra$ decay series according to mobility of the radionuclides. The radioactivity concentration of $^{40}K$ showed a negative correlation with organic matter content. The concentration of $^{40}K$ in the lake sediment was lower than that in the river sediment.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1282-1288
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• 2020

In the first study, the Radon emanation and radiological hazards associated with radionuclides in soil samples, collected from 9 various date palm farms located in 3 different districts in Saudi Arabia were determined through a high purity Germanium (HPGe) gamma-ray spectrometer. The estimated average values of Radon emanation coefficient and Radon mass exhalation rate for soil samples were 0.535 ± 0.016 and 50.063 ± 7.901 mBqkg^-1h^-1, respectively. The annual effective dose of radionuclides in all sampling locations was found to be lower than UNSCEAR's recommended level of 0.07 mSvy^-1 for soil in an outdoor environment. In the secondary study, gross α and gross β activities in soil and date palm pits samples were measured by a low background α/β counting system. Average values of gross α and gross β activities in soil and date palm pits samples were 5.761 ± 0.360 Bqkg^-1, 38.219 ± 8.619 Bqkg^-1 and 0.556 ± 0.142 Bqkg^-1, 24.266 ± 1.711 Bqkg^-1, respectively.

• Nuclear Engineering and Technology
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• v.38 no.6
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• pp.459-482
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• 2006

A geochemical approach to the long-term safety of waste disposal is discussed in connection with the significance of actinides, which shall deliver the major radioactivity inventory subsequent to the relatively short-term decay of fission products. Every power reactor generates transuranic (TRU) elements: plutonium and minor actinides (Np, Am, Cm), which consist chiefly of long-lived nuclides emitting alpha radiation. The amount of TRU actinides generated in a fuel life period is found to be relatively small (about 1 wt% or less in spent fuel) but their radioactivity persists many hundred thousands years. Geological confinement of waste containing TRU actinides demands, as a result, fundamental knowledge on the geochemical behavior of actinides in the repository environment for a long period of time. Appraisal of the scientific progress in this subject area is the main objective of the present paper. Following the introductory discussion on natural radioactivities, the nuclear fuel cycle is briefly brought up with reference to actinide generation and waste disposal. As the long-term disposal safety concerns inevitably with actinides, the significance of the aquatic actinide chemistry is summarized in two parts: the fundamental properties relevant to their aquatic behavior and the geochemical reactions in nanoscopic scale. The constrained space of writing allows discussion on some examples only, for which topics of the primary concern are selected, e.g. apparent solubility and colloid generation, colloid-facilitated migration, notable speciation of such processes, etc. Discussion is summed up to end with how to make a geochemical approach available for the long-term disposal safety of nuclear waste or for the performance assessment (PA) as known generally.

• BMB Reports
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• v.29 no.1
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• pp.73-80
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• 1996

The effect of albumin on phosphatidylcholine (PC) metabolism in Hep-G2, 3T3-H.ras, and 3T3 cells pre-labelled with [Me-$^3H$]choline was studied. The [$^3H$]choline was more efficiently taken up and incorporated into cellular phospholipids in 3T3-H.ras cells than in Hep-G2 and 3T3 cells. In each of the three cell lines, most of the [$^3H$]choline metabolized into the phospholipids was incorporated into PC and only minor was incorporated into lysophosphatidylcholine (LPC). Bovine serum albumin stimulated the release of [$^3H$]LPC and [$^3H$]PC from each of the three cell lines pre-labelled with [$^3H$]choline. [$^3H$]PC was also released in the absence of albumin but [$^3H$]LPC was not. The efficiency of LPC secretion represented as the proportion of medium [$^3H$]LPC to cellular [$^3H$]choline lipid during a chase period is approximately 9 to 14 times greater in 3T3 cells compared with the transformed 3T3-H.ras and Hep-G2 cells. A similar comparison of published data for rat hepatocytes with Hep-G2 shows secretion to be 35~75 times greater from the rat hepatocytes than from Hep-G2. Also, PC secretion from 3T3 cells was 1.6 times more effective than from 3T3-H.ras, whereas rat hepatocytes secrete PC 2.8~3.8 times more effectively than does Hep-G2. The measurement of specific radioactivity of cellular PC in pre-labelled 3T3 cells showed it to be similar to that of the secreted PC. However, the specific radioactivity of secreted LPC was markedly lower than that of the cellular PC, which suggests that LPC is being secreted from a PC pool distinct from that used for PC secretion.

• Journal of Korea Technology Innovation Society
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• v.2 no.3
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• pp.94-106
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• 1999

In Korea Basic Science Institute(KBSI) the remote data analysis system is developed for the joint use of advanced equipments. This system enables the researchers to access the datas which are produced at KBSI and analyse them by Java program on the Web,. Except Web browser such as Internet Explorer or Netscape Navigator no additional softwares are required for analysing data. We have developed remote data analysis systems for five major equipments which KBSI supports for the researchers, The systems which are developed are those for NMR spectrometer High Reso-lution Tandem mass Spectrometer Microscopic Imaging System DNA Sequencer and Natural Ra-dioactivity Measruement System, These programs work on any computer platform and any operat-ing system only if the internet is available. This remote data analysis system will be served as a part of Collaboratory the remote collaborative system.

• The Journal of Natural Sciences
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• v.18 no.1
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• pp.55-63
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• 2007

This research was conducted to investigate the effects of calcium solution spray on the accumulation of calcium into apple fruit. $^{45}_{CaCl_2}$ applied to fruit with different growth stages showed that more $^{45}Ca$ was penetrated into fruits when applied in the late stage than early stage. Slight radioactivity was detected only in pedicel except leaf when $^{45}Ca$ was treated on the leaves proximate to the fruit. When the Ca was treated on fruit surface only, calcium contents of fruit was increased.