• Journal of Radiation Protection and Research
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• v.7 no.1
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• pp.34-48
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• 1982

The prime purpose of this study is to realize an index quantity, absorbed dose index, defined by the ICRU for the characterization of ambient radiation level at any location for the purpose of radiation protection. The experiment has been designed to be carried out in two phases, namely, preliminary and main experiment. In the primary study a 30cm diameter sphere of polyethylene was used, while in the main experiment that of tissue equivalent material was fabricated and used. Both experiments were performed in the gamma-ray fields of $^{137}Cs\;and\;^{60}Co$, and in a neutron beam of thermal column of the TRIGA MARK-II research reactor. In the measurement of gamma-ray absorbed dose TLD-700 $(^{7}LiF)$ chips were used, and for the neutron dose both Au activation foils and TLD chips (TLD-600 $(^{6}LiF)$ and TLD-700 for the discrimination of gamma-ray contribution) were used. Theoretical assessment of the absorbed dose in the sphere phantom has been carried out in accordance with the Ehrlich's idea that deduced on the basis of Burlin's cavity theory in the case of gamma-ray irradiation. For the analysis of neutron dose fluence-KERMA rate conversion method was used. The explanation on the dose assessment is given in detail. Results obtained were numerically and statistically analyzed and the depth dose distributions are presented in the graphic forms with normalized values. In the concluding remarks, the possibility and difficulty of realizing the index quantity, including questions and problems to be solved are mentioned.

• Nuclear Engineering and Technology
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• v.1 no.2
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• pp.91-101
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• 1969

Resistivity changes of n-type float-zone silicon crystals with 6.4$\times$10$^{14}$ to 1.25$\times$10$^{17}$ phosphorus atoms/㎤ due to irradiation by (1) 1 MeV electrons, (2) two types of research reactors, and (3) $Co^{60}$ ${\gamma}$-ray sources were investigated. The results were analyzed on the basis of a simple exponential formula derived by Buehler. While the formula gave a fair fit in the low fluence range in most cases, the deviation was quite appreciable in the case of 1 MeV electron irradiation, and a linear change gave better fit in some cases. The large change in the carrier removal rate in electron-irradiated samples in the high fluence range was analyzed in detail in terms of the Fermi level cross-over of the defect levels. Based on the damage constants evaluated from the initial portion of data where the formula was applicable, the relative effectiveness of various radiation sources in causing the resistivity change in n-type silicon was compared. The TRIGA Mark II reactor neutrons, for example, were found to be about 40 times more effective than 1 MeV electrons. The dependence of the damage constant on the initial carrier concentration was also examined. The physical basis of the exponential law and the effect of the Fermi level cross-over of the defect levels on the resistivity change in the high fluence ranges are discussed.

• Journal of Nutrition and Health
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• v.31 no.2
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• pp.206-212
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• 1998

This study was undertaken to analyze the iodine content in commonly donsumed Korean foods. Food samples were purchased from 3 randomly selected markets. The iodine contents in foods were determined by nuetron activation analysis (NAA). All irradiation of food samples were done at a pnueumatic transfer system (thermal nuetron flux : 1 $\times$1013n/$\textrm{cm}^2$.s) of the TRIGA MarkIII research reactor in the Korea Atomic Energy Research Institute . The results indicated that the iodine content was high in seaweeds, fishes, and iodine-enriched eggs in that order and very low in grain, beans , fruits and vegetables. Edible seaweeds contained iodine levels of between 13,700 and 1,790, 600$\mu\textrm{g}$/kg. Levels of iodine in fishes and shellfishes were between 478 and 2, 840$\mu\textrm{g}$/kg. Ordinary eggs contained 314$\mu\textrm{g}$/kg iodine, but iodine -enriched eggs contained 1,869$\mu\textrm{g}$/kg. The average concentration of iodine in milk was 207$\mu\textrm{g}$/kg. There was seasonal variation in the iodine content of milk , levels were highest in winter milk(230$\mu\textrm{g}$/kg) and lowest in summer milk(180$\mu\textrm{g}$/kg).The idodine contents of most vegetables and fruits were below 10$\mu\textrm{g}$/kg. The iodine contents of most vegetables and fruits were below 10$\mu\textrm{g}$/kg. From high to low , the sequence of foods with high iodine content in one serving was as follows ; sea tangle , sea mustard, iodine-enriched eggs, fish , laver and milk. This study may provide basic data on the iodine content of foods consumed by Korean which have not yet been analyzed .

• Journal of Nutrition and Health
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• v.31 no.2
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• pp.213-219
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• 1998

This study was conducted to compare and evaluate the iodide specific ion electrode method (ISE) and neutron activation analysis method (NAA) for determining iodine in human milk and cow milk. The neutron irradiation and counting operations were carried out at the TRIGA Mark-III reactor facility of the Korea Atomic Energy Research Institute. The mean concentrations of iodine in human milk samples by the ISE and the NAA were 1450$\mu\textrm{g}$/L and 1350$\mu\textrm{g}$/L, respectively. The levels were not significantly different. In cow milk samples , the mean concentrations of iodine by the ISE and the NAA were 250$\mu\textrm{g}$.L and 200$\mu\textrm{g}$/L, respectively. here, the ISE reading was significantly higher than the NAA. reading. The correlations of the two methods were 0.92(p<0.001) for human milk samples and 0.65 for cow milk samples . The coefficient of variation was 8.3% in the ISE and 4.9% in the NAA. Therefore, the iodide specific ion electrode method is sample and fast method, but probably not in processed milk since free sulfhydryl groups in milk are also detected by the iodide electrode. However, these also indicate that the ISE method may be applicable to human milk and pasteurized milk if the conventional pasteurization time-temperature relationship of standards is not exceeded. On the other hand, the NAA method , which is independent of chemical forms and matrix, can be used for determining iodine in all kinds of milk and foods.

• Journal of the Korean Chemical Society
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• v.15 no.4
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• pp.191-197
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• 1971

Ruthenium content in highly purified palladium metal (99.9%) was determined by counting $^{105}Rh$ nuclide which was produced by $^{104}Ru(n,{\gamma};{\beta}^-)^{105}Rh$ nuclear reaction. Palladium sample and ruthenium standard were irradiated by neutron with the Pneumatic Transfer System of TRIGA MARK II reactor. Palladium and ruthenium were dissolved by treating with aqua-regia and by fusing with sodium peroxide flux respectively. $^{105}Rh$ was separated through anion and cation exchange resin columns. The ruthenium content was determined by comparing the $^{105}Rh$ activities, obtained from the palladium sample, with that from pure ruthenium standard. The detection limit of ruthenium by the present method is about 1 ppm of ruthenium in 10 mg of palladium, which is approximately 40 times more sensitive than that of the conventional radioactivation method which employs $^{102}Ru(n,{\gamma})^{103}Ru$ nuclear reaction.

• 한국해양학회지
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• v.4 no.1
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• pp.9-16
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• 1969

The sand drift movement at Young Il Bay area was tentatively investigated using Co-60 glass sand. Grain size and specific gravity of the glass sand which has originally contained natural cobalt, Co-59, was made similar to those of the real coastal sand, and was irradiated in a beam port of the reactor Triga Mark II to make the glass sand radioactive by the reaction of 59Co(n, r)60Co. The radioactive cobalt glass sand was deposited on the preselected point of sea bed, and, after a couple of weeks, the drift of sand was traced by means of specially designed water-proof G-M detector. Net counts at each point were plotted to figure out equicount lines and consequently such aspects as the direction of sand drift movement, the scope of distribution and the relative drift velocity etc. were indicated.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.104-111
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• 1993

Trace elements are important components in the biological system, as a structural material and metabolic controller. Neutron activation analysis (NAA) with high neutron flux and high energy resolution Ge (Li) detector coupled to multichannel analyzer (MCA) has been one of the most accurate method for the determination of ultra-trace level components, and is applicable to biological material. In human body, the NAA can be used for quantitation of trace elements in various organs and tissue with endocrinological and metabolic disease and industrial metal poisoning. In this study, Triga Mark III nuclear reactor in Korea Atomic Research Institute was used for quantitation of trace eleement in human lung cancer tissues by neutron activation analysis. In the squamous cell carcinoma tissues, Br, Hg, La, Sb, Sc, Cl, Fe and I content were lower than normal lung tissues, and K, Rb and Se content were higher. In the adenocarcinoma tissues, Fe, Au, La, Sc and Zn content were lower than normal lung tissues, and Rb, Co and Se content were higher. Rb content was higher in the adenocarcinoma tissues than in the squamous cell carcinoma tissues. Fe and Na content were higher in the squamous cell carcinoma tissues than in the adenocarcinoma tissues.

• Journal of the Korean Chemical Society
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• v.8 no.2
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• pp.47-56
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• 1964

When a developed paper partition chromatogram was irradiated by means of the pneumatic tube system of the Korean research reactor (neutron flux: 1.5 ${\times}10^{12}n/cm^2$sec.) the qualitative confirmation of the developed spot on the chromatogram was possible. In the case of an organic halogen compounds (chloro-acid, chloro-ester, iodide, and fluoride) the spot analysis was possible by the present method whereas the same spot could not give the distinct coloring with a common coloring reagents. Filterpaper thickness calibration and activity calibration induced by irradiation of the components of the filter paper, which were a source of erraneous interpretation of the spot, were searched and an average filterpaper calibration method and filter paper activity were improvised to obtain a good qualitative analysis of the spot. Finally the use and applicability of this method for the analysis identification of an organic halogen compound were evaluated. As the filter paper phase an ordinary phase (Whatmann #1, filter paper) and reversed phase (liquid paraffin impregnated) were used.

• Journal of the Korean Chemical Society
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• v.8 no.2
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• pp.88-91
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• 1964

A rapid and simple method is described here for the determination of scandium in monazite by neutron activation analysis. The sample is irradiated for 20 hours at the neutron flux of $10^{12}$ thermal neutrons/$cm^2$/sec in the TRIGA MARK Ⅱ reactor, after which the sample is decomposed by fusion with concentrated sulfuric acid. The scandium-46 together with scandium carrier are separated from the irradiated sample by precipitating with ammonia, and are extracted by solvent extraction of the thiocyanate complex into ether. The induced radioactivity is measured by gamma scintillation spectrometry using the Multichannel Pulse Height Analyzer connected with 2"${\times}$2" NaI(Tl). The chemical yield is determined gravimetrically by precipitating scandium with mandelic acid. In order to check the efficiency of scandium separation and the errors from interfering activities of the other elements, scandium was separated by the cation exchange resin column, and the results from both samples were compared each other, which showed that the chemical procedure used in this work was as selective as the ion-exchange method with respect to scandium separation. The scandium contents in Korean monazite were found to be about 12 p. p. m.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.2
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• pp.79-86
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• 2009

Concrete materials in nuclear facilities may become contaminated or activated by various radionuclides through different mechanism. Decommissioning and dismantling of these facilities produce considerable quantities such as concrete structure, rubble. In this paper, the characteristics distribution of the radionuclide have been investigated for the effects of the heating and grinding test for aggregate size such as gravel, sand and paste from decommissioning of the TRIGA MARK II research reactor and uranium conversion plant. The experimental results showed that most of the radionuclide could be removed from the gravel, sand aggregate and concentrated into a paste. Especially, we found that the heating temperature played an important role in separating the radionuclide from the concrete waste. Contamination of concrete is mainly concentrated in the porous paste and not in the dense aggregate such as the gravel and sand. The volume reduction rate could be achieved about 80% of activated concrete waste and about 75% of dismantled concrete waste generated from UCP.