• 방사선산업학회지
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• 제5권1호
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• pp.21-24
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• 2011

This study was conducted to evaluated the sensory properties of Miyukgook, Korean seaweed soup, with gamma-irradiated Undaria pinnadifida for enhancing the storage of the harvested seaweed. The harvested seaweed was irradiated at the doses of 1, 3, 5, and 10 kGy. The Miyukgook was made by following the general recipe. The values of pH and acidity of the Miyukgook were not changed by the irradiation of harvested Undaria. The sensory evaluation result showed that the preference scores in all the sensory properties was a little decreased when it was irradiated, but sensory score of less than 5 kGy samples was similar in all terms. Therefore, it was considered that gamma irradiation with less than 5 kGy was effective for improvement of the storage stability of U. pinnatifida without the changes in the sensory of its major cooked food, Miyukgook.

• 방사선산업학회지
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• 제4권1호
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• pp.73-77
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• 2010

In recent day, there is much interest in the biocidal activity of silver since silver is known to be safe and effective as disinifectant and biocidal material against coliforms and viruses. In this study, hydrogels containing silver acetate as antibacterial agent have been prepared using gamma rays irradiation. The hydrogels are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG), carrageenan and silver acetate. The concentration of solution was 9 wt%. The ratio of PVP : PEG : carrageenan was 6 : 1 : 2. The concentration of the silver acetate were 0, 0.01, 0.03, 0.05 and 0.07% and Gamma irradiation dose was 25 kGy. The Gamma irradiation dose in hydrogels with 0.01% silver acetate were 20 kGy, 35 kGy, 50 kGy, 65 kGy, and 80 kGy. The results showed that 0.01% silver acetate concentration of hydrogels by 25 kGy irradiation dose showed the highest antibacterial activity against E. coli and Staphylococcus aureus. Moreover, antibacterial activity of various Gamma irradiation dose in hydrogels treated 0.01% silver acetate showed highest 35 kGy irradiation dose against Staphylococcus aureus.

• 방사선산업학회지
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• 제6권2호
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• pp.139-145
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• 2012

Gold nanoparticles (GNPs) have led to the development of a new field in the diagnosis and treatment of diseases such as cancer. An efficient synthesis of gold nanoparticles within the range of 8~57 nm was established by ${\gamma}-ray$ irradiation. The good point of a radiation-based method is the production of gold nanoparticles with a higher concentration and narrower size distribution compared with conventional methods. The size of gold nanoparticles was controlled using two methods. : (i) varying the ${\gamma}-ray$ irradiation dose of 10 to 25 kGy and (ii) varying the concentration of $HAuCl_4$ solution from 4 to 40 mM. In addition, the GNPs were radiolabeled using $[^{125}I]NaI$ in a simple and fast manner with high yields. The produced gold nanoparticles were characterized using a transmission electron microscopy (TEM), a UV-visible spectrophotometer, and a radio-TLC imaging scanner. From these results, these radiolabeled GNPs can be applicable for a radioisotope tag of biomolecules.

• 방사선산업학회지
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• 제5권3호
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• pp.197-202
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• 2011

In this study, an Ag-polyaniline-silica (Ag-PANI-silica) nanoparticle was evaluated as a radioisotope carrier. An Ag-PANI-silica nanoparticle was incubated in the $^{125}I$ solution for a duration of 24 hr to test its radioisotope absorptivity. During the incubation, radioactivity of the nanoparticle was measured at 3, 6, 12, and 24 hr. After a 24 hr incubation, $^{125}I$-Ag-PANI-silica nanoparticle was incubated in a fresh saline for a duration of 48 hr to check its stability. Additionally, the $^{125}I$-Ag-PANI-silica nanoparticle was injected to the ICR mouse to investigate its in-vivo distribution characteristics. The $^{125}I$ absorption yield of the Ag-PANI-silica nanoparticle was higher than 95% after a 6 hr incubation period in the $^{125}I$ solution. And $^{125}I$-Ag-PANI-silica was stable for 48 hr at 80% yield at room temperature. The SPECT/CT image of a mouse that received $^{125}I$-Ag-PANI-silica complex showed that the $^{125}I$-Ag-PANI-silica complex was distributed in the lung, stomach and thyroid at 30 min post injection. From these results, the Ag-PANI-silica nanoparticle has good radio-iodine carrying property and can be applicable for the purpose of diagnosis and therapy.

• 방사선산업학회지
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• 제5권4호
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• pp.325-330
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• 2011

To predict the details of flow in industrial process unit, single photon emission computed tomography (SPECT) is a promising technique. Recently, industrial SPECT based on medical system has developed by researchers of the Korea Atomic Energy Research Institute (KAERI) and Hanyang University. In the present study, to confirm the effect of the number of detectors on image quality, and determine the optimal number of detectors in industrial SPECT, industrial SPECT system with various geometries were evaluated by the Monte Carlo simulation. CsI(Tl) detectors ($12mm{\times}12mm{\times}20mm$) with collimators (the geometric resolution of collimator $R_g$ was 4 cm at the center of the 30 cm diameter cylindrical vessel object) were modeled in a hexagonal array, and the point sources of $^{99m}Tc$, $^{68}Ga$, and $^{137}Cs$ were simulated at the center of the cylindrical vessel object using the MCNPX code. Then, the reconstruction images of each geometry were reconstructed using the expectation maximization (EM) algorithm. In this study, the reciprocity theorem was used to improve computation time required for system matrix of the EM algorithm. The result shows that the resolution of the reconstructed image was significantly improved by increasing the number of detectors in industrial SPECT system and more than 60 detectors will be required for the resolution of the reconstructed image.

• 방사선산업학회지
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• 제4권4호
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• pp.373-379
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• 2010

Cellulose, chitin, chitosan and hyaluronic acid are well known as polysaccharides. These polysaccharides have many effects on cell growth and differentiation. Cell activation increases with increasing the polysaccharides concentration. In this study, gelatin scaffold containing microorganism fermented cellulose, citrus gel were prepared by using irradiation technique. Physical properties of the scaffolds were investigated as a function of the concentrations of gelatin and citrus gel and the cell attachment, cell morphology and inflammation of the scaffolds also were characterized for regeneration of skin tissue.

• 방사선산업학회지
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• 제12권4호
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• pp.303-310
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• 2018

Since Roentgen discovered X-rays, radiation sources have been utilized for many areas such as agriculture, industry, medicine and fundamental chemical research. As a result, human society has gained lots of benefits. However, if a radioactive material is used for the malicious purpose, it causes serious consequences to humanity and environment. Consequently, international organizations including International Atomic energy Agency (IAEA) have been emphasizing establishment and implementation of security management to prevent sabotage and illicit trafficking of radioactive materials. For this reason, the rule of technical standards of radiation safety management was revised and the public notice of security management regarding radioisotope was legislated in 2015 by Nuclear Safety and Security Commission (NSSC). Several radioactive sources which have to be regulated under the above rule and the public notice have been utilized in Advanced Radiation Technology Institute (ARTI) of Korea Atomic Energy Research Institute (KAERI). In order to control them properly, security management system such as access control and physical protection has been adapted since 2015. In this paper, we have analyzed the public notice of NSSC and its field application case. Based on the results, we are going to draw improvement on the public notice of NSSC and security system.

• 한국안전학회지
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• 제33권6호
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• pp.136-143
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• 2018

In this study, we conducted a pilot study on the multiple spurious operations (MSO) analysis in the fire probabilistic safety assessment (PSA) of domestic nuclear power plant (NPP) to identify the degree of influence of the operator actions used in the MSO mitigation strategies. The MSO scenario of the domestic reference NPP selected for this study is refueling water tank (RWT) drain down event. It could be caused by spurious operations of the containment spray system (CSS) of the reference NPP. The RWT drain down event can be stopped by the main control room (MCR) operator actions for stopping the operation of CSS pump or closing the CSS motor operated valve if the containment spray actuation signal (CSAS) is spuriously actuated. Outside the MCR, it can be stopped by operator actions for closing the CSS manual valves or motor operated valve or stopping the operation of CSS pump. The quantification result of a fire PSA model that takes into account all recovery actions for the RWT drain down event lead to risk reduction by about 95%, compared with quantification result of fire PSA model without considering them. Among the various operator actions, the recovery action for the spurious CSAS operations and the operator action for the manual valve are identified as the most important operator actions. This study quantitatively showed the extent to which the operator actions used as MSO countermeasures have affected the fire PSA quantification results. In addition, we can see the rank of importance among the operator recovery actions in quantitative terms.

• 방사성폐기물학회지
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• 제17권1호
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• pp.121-126
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• 2019

원자력발전소 해체과정에서 방사화 재고량에 대한 평가는 방사선 환경에 정보를 제공함으로써 해체 계획을 수립하는데 중요한 정보를 제공한다. 원자로 운전 정지 후 원자로 및 관계시설에서의 축적된 방사능은 노심 구조물, 반사체 및 차폐체 등의 구조재가 중성자 조사에 의해 방사화된것이다. 방사화생성물 중 $^{36}Cl$ 과 $^{41}Ca$ 은 반감기와 화학적 물리학적 특성에 의해 해체 처분 관점에서 매우 중요한 핵종이며 이에 따라 본 연구에서는 차폐 콘크리트 내 생성량을 평가하였다. MCNPX 코드를 사용하여 중성자속과 반응단면적을 계산하였으며 이 결과를 토대로 ORIGEN2 코드를 사용하여 방사화생성물의 양을 평가하였다.

• 한국재료학회지
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• 제29권4호
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• pp.271-276
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• 2019

Oxide-dispersion-strengthened (ODS) alloy has been developed to increase the mechanical strength of metallic materials; such an improvement can be realized by distributing fine oxide particles within the material matrix. In this study, the ODS layer was formed in the surface region of Zr-based alloy tubes by laser beam treatment. Two kinds of Zr-based alloys with different alloying elements and microstructures were used: KNF-M (recrystallized) and HANA-6 (partial recrystallized). To form the ODS layer, $Y_2O_3$-coated tubes were scanned by a laser beam, which induced penetration of $Y_2O_3$ particles into the substrates. The thickness of the ODS layer varied from 20 to $55{\mu}m$ depending on the laser beam conditions. A heat affected zone developed below the ODS layer; its thickness was larger in the KNF-M alloy than in the HANA-6 alloy. The ring tensile strengths of the KNF-M and HANA-6 alloy samples increased more than two times and 20-50%, respectively. This procedure was effective to increase the strength while maintaining the ductility in the case of the HANA-6 alloy samples; however, an abrupt brittle facture was observed in the KNF-M alloy samples. It is considered that the initial microstructure of the materials affects the formation of ODS and the mechanical behavior.