검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 52

        1.
        2023.11 구독 인증기관·개인회원 무료
        The radiological characterization of SSCs (Structure, Systems and Components) plays one of the most important role for the decommissioning of KORI Unit-1 during the preparation periods. Generally, a regulatory body and laws relating to the decommissioning focus on the separation and appropriate disposal or storage of radiological waste including ILW (intermediate level waste), LLW (low level waste), VLLW (very low level waste) and CW (clearance waste), aligned with their contamination characteristics. The result of the preliminary radiological characterization of KORI Unit-1 indicated that, apart from neutron activated the RV (reactor vessel), RVI (reactor vessel internals), and BS (biological shielding concrete), the majorities of contamination were sorted to be less than LLW. Radiological contamination can be evaluated into two methods. Due to the difficulties of directly measuring contamination on the interior surfaces of the pipe, called CRUD, the assessment was implemented by modeling method, that is measuring contamination on the exterior surfaces of the pipes and calculating relative factors such as thickness and size. This indirect method may be affected by the surrounding radiation distribution, and only a few gamma nuclides can be measured. Therefore, it has limitation in terms of providing detailed nuclide information. Especially, α and β nuclides can only be estimated roughly by scaling factors, comparing their relative ratios with the existing gamma results. To overcome the limitation of indirect measurement, a destructive sampling method has been employed to assess the contamination of the systems and component. Samples are physically taken some parts of the systems or components and subsequently analyzed in the laboratory to evaluate detailed nuclides and total contamination. For the characterization of KORI Unit-1, we conducted the radiation measurement on the exterior surfaces of components using portable instruments (Eberline E-600 SPA3, Thermo G20-10, Thermo G10, Thermo FH40TG) at BR (boron recycle system) and SP (containment spray system) in primary system. Based on these results, the ProUCL program was employed to determine the destructive sample collection quantities based on statistical approach. The total of 5 and 8 destructive sample quantities were decided by program and successfully collected from the BR and SP systems, respectively. Samples were moved to laboratory and analyzed for the detail nuclide characteristics. The outcomes of this study are expected to serve as valuable information for estimating the types and quantities of radiological waste generated by decommissioning of KORI Unit-1.
        2.
        2023.05 구독 인증기관·개인회원 무료
        Molten Salt Reactor (MSR) is one of Generation-IV nuclear reactors that uses molten salts as a fuel and coolant in liquid forms at high temperatures. The advantages of MSR, such as safety, economic feasibility, and scalability, are attributed from the fact that the molten salt fuel in a liquid state is chemically stable and has excellent thermo-physical properties. MSR combines the fuel and coolant by dissolving the actinides (U, Th, TRU, etc.) in the molten salt coolant, eliminating the possibility of a core meltdown accident due to loss of coolant (LOCA). Even if the molten salt fuel leaks, the radioactive fission products dissolved in the molten salt will solidify with the fuel salt at room temperature, preventing potential leakage to the outside. MSR was first demonstrated at ORNL starting with the Aircraft Reactor Experiment (ARE) in 1954 and was extended to the 7.4 MWth MSRE developed in 1964 and operated for 5 years. Recently, various start-ups, including TerraPower, Terrestrial Energy, Moltex Energy, and Seaborg, have been conducting research and development on various types of MSR, particularly focusing on its inherent safety and simplicity. While in the past, fluoride-based molten salt fuels were used for thermal neutron reactors, recently, a chlorine-based molten salt fuel with a relatively high solubility for actinides and advantageous for the transmutation of spent nuclear fuel and online reprocessing has been developing for fast neutron spectrum MSRs. This paper describes the development status of the process and equipment for producing highpurity UCl3, a fuel material for the chlorine-based molten salt fuel, and the development status of the gas fission product capturing technologies to remove the gaseous fission products generated during MSR operation. In addition, the results of the corrosion property evaluation of structural materials using a natural circulation molten salt loop will also be included.
        3.
        2022.10 구독 인증기관·개인회원 무료
        Nuclear spent fuel (SNF) disposal in deep geological repositories is considered as one of sound options for the long-term and safe sequestration of radiotoxic SNF and the sustainable use of nuclear energy. The chemical behaviors of various radionuclides originated from SNF should be well understood to evaluate the migrational behaviors of radionuclides and their reactions and interactions with various geochemical components. Formation of secondary minerals, colloids, other insoluble precipitates is of interest since the concentrations of radionuclides in groundwaters can be limited by the solubility of those solid phases. Particularly when evaluating their solubility, the use of well-defined solid materials in terms of chemical composition and molecular structure is crucial to obtain reliable measurement results. In this study, a synthetic calcium uranyl silicate (Ca-U(VI)-silicate, or uranophane) was prepared and characterized by using various analytical methods including powder X-ray diffraction (pXRD), scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX), and vibrational (FTIR and Raman) spectroscopies. Uranyl silicate minerals are significant to the disposal of nuclear wastes. Our simulation demonstrates that uranophane (Ca[UO2SiO3OH]2·5H2O), one having a U:Si ratio of 1:1, can be a mineral species limiting U(VI) solubility under groundwater conditions in Korea. For the preparation of Ca-U(VI)-silicate, we applied a two-step hydrothermal synthetic procedure reported in literature with modification. Briefly, we conclude that the obtained mineral phase is the ‘α-uranophane’; our characterization results show that the structural and spectroscopic properties of the synthetic Ca-U(VI)-silicate agree well with those of α-uranophane. For instance, the pXRD patterns obtained from the solid show nearly identical diffraction peak positions with those from the reference XRD pattern. From IR and Raman spectroscopy it is noticed that the stretching modes of UO2 2+ and SiO4 4- ions result in strong absorption bands in a region of 700 ~ 1,100 cm-1. Elemental compositions of the synthetic solids were also estimated by using EDX analysis, which results in a Ca:U:Si ratio close to 1:2:2 on average. However, we found that it is difficult to obtain good crystallinity of uranophane, which can be observable by using SEM and its image analysis. We believe that this work serves as a model study to provide synthetic routes of radionuclide-related mineral phases and applicable solid phase characterization methods. In the presentation, the potential use of the U(VI)-silicate solid phase for the upcoming groundwater solubility measurements will be discussed. Keywords: Hexavalent Uranium, Silicate
        4.
        2022.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effect of oxidation time on the characteristics and mechanical properties of spent nuclear fuel cladding was investigated using Raman spectroscopy, tube rupture test, and tensile test. As oxidation time increased, the Raman peak associated with the tetragonal zirconium oxide phase diminished and merged with the Raman peak associated with the monoclinic zirconium oxide phase near 333 cm−1. Additionally, the other tetragonal zirconium oxide phase peak at 380 cm−1 decreased after 100 d of oxidation, whereas the zirconium monoclinic oxide peak became the dominant peak. The oxidation time had no effect on the tube rupture pressure of the oxidized zirconium alloy tube. However, the yield and tensile stresses of the oxidized nuclear fuel cladding tube decreased after 100 d of oxidation. The results of the scanning electron microscopy and transmission electron microscopy were represented with the in-situ Raman analysis result for the oxide characteristics generated on the cladding of spent nuclear fuel.
        4,000원
        5.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The PoN (Proof of Nonce) distributed consensus algorithm basically uses a non-competitive consensus method that can guarantee an equal opportunity for all nodes to participate in the block generation process, and this method was expected to resolve the first trilemma of the blockchain, called the decentralization problem. However, the decentralization performance of the PoN distributed consensus algorithm can be greatly affected by the network transaction transmission delay characteristics of the nodes composing the block chain system. In particular, in the consensus process, differences in network node performance may significantly affect the composition of the congress and committee on a first-come, first-served basis. Therefore, in this paper, we presented a problem by analyzing the decentralization performance of the PoN distributed consensus algorithm, and suggested a fairness control algorithm using a learning-based probabilistic acceptance rule to improve it. In addition, we verified the superiority of the proposed algorithm by conducting a numerical experiment, while considering the block chain systems composed of various heterogeneous characteristic systems with different network transmission delay.
        4,000원
        6.
        2022.03 구독 인증기관 무료, 개인회원 유료
        WAIS in South Korea and WEU Inc. in Philadelphia hosting the 22nd World Peace Island Forum: Remembering Jeju King Cherry Trees Bio-diplomacy (1943) in Washington D.C. and the first Korean Congress Democracy (1919) in Philadelphia which organized by the Korean Provisional Government from March 22 to 24, 2022. We want to propose cultural historic events which connect American and Korean society, such as the Trip to Faith and Liberty Hall that relate to the integration processes of Korean and American Democracy. Dean Max Friedman of American University calls the Jeju King cherry trees cultural event bio-diplomacy among world citizens. In addition, the Korean embassy evaluated the cherry tree event as a new kind of bio-diplomacy approach which paves the way for understanding different cultures in different countries. The aim of this paper is to share present contexts and meanings about both the first Korean Congress Democracy (1919) and Bio-diplomacy (1943). We had also the 2022 GAN Korea Jeju to Philadelphia Webinar Conference: Diversity as a New Diversity for Global Ageing Network in New Normal: Jeju Village Healing, PASSi Asian Culture, Japanese Indigenous Peace Culture, and Busan Smart Health Care approach.
        4,000원
        7.
        2021.06 구독 인증기관 무료, 개인회원 유료
        In this article, firstly, we talk about why we respond to “climate change impacts in nature and society” educationally. Secondly, we try to find ways that Jeju also has the ability to halt biodiversity loss and apply nature-based solutions to conserve biodiversity, enhance resilience, and so improve the well-being of the people on the island and in turn to improve the well-being of the people on the planet at the grass roots level of UNESCO internationally protected areas. Thirdly, we try to develop World Environment University Online School Leads Establishment of World Environment University so called “Lead WEU.” We will announce “World Environment University Online School Leads Establishment of World Environment University” at Private Meeting of the 2020 World Conservation Congress on September 9, 2021 in Marseille of France. We propose ”Jeju Global Governance of World Heritage; Climate Change Impacts and Integrated Management of UNESCO internationally Protected Area, at the graduate class of Jeju National University from September 2 to December 9, 2021. The core program centered at the University itself would be developed initially on the basis of the comparative advantage offered by its location in Jeju and the quality of faculty, full and part time, that could be recruited to the University.
        4,000원
        9.
        2020.06 구독 인증기관 무료, 개인회원 유료
        The University will contribute, through its high quality of education, training and research, to the containment, reduction and management of the problems confronting humanity in the transition to sustainable way of life utilizing the latest technologies of distance learning. Through international collaboration and leadership, it will generate, mobilize and share knowledge, experience and skills throughout the world so as to promote equitable and sustainable progress and to preserve and enhance the natural world on which humanity depends. As merit of the location of center in Northeastern Asia and North and South countries, Jeju Island has a remarkable natural beauty matching with unique environmental culture tradition, and a wide range of expertise, connections and capabilities in regard to global commerce, finance and transportation, and to the management of watersheds and biodiversity as a newly established international free city, all of which are relevant to world environment of sustainable development.
        4,000원
        10.
        2020.03 구독 인증기관 무료, 개인회원 유료
        The name of the University. While there is a close relationship between the environment and peace, this should be reflected in the establishment of an institute or program rather that in the name of the University which should be, as originally conceived, the World Environment University. The credibility of the University will depend on the involvement in it from the beginning of highly influential leaders of the world environment movement. There is no better way of ensuring this than to obtain the formal involvement of IUCN which has in its membership most of the leading nongovernmental and governmental organizations of the environment and conservation movement
        4,000원
        15.
        2019.03 구독 인증기관 무료, 개인회원 유료
        We want to have an opportunity to learn in a global context why GAN is so important to Jeju as Korea's largest Island in a multi-cultural society. Politically, Jeju Island succeeds have to survive ordeal from Jeju 4.3 Grand Tragedy. Geologically, as Jeju Island is located at center of East Asia, it has benefits from easy access to main cities to the island such as Beijing, Shanghai, Tokyo, Osaka, Seoul, Busan, Hong Kong, Taipei and so on. Environmentally, as Jeju was designated UNESCO Biosphere, World Natural Heritage and Geo parks, we want to keep it as a longevity island. Culturally, as we recognize it as a specialized in Western countries by human peace, Jeju as a World Peace Island tries to integrate aging human life agenda into part of a human life one. As the result, we suggest “Korea Care into Global Humanity in the Asia Pacific Context” as integrated policy agenda of both Korea and Peace Island villages for the 2021 GAN Biennial Conference from September 26 to 30, 2021 in Jeju Island Korea. As it based on village healing by villagers, Jeju island is small, as there is slrong soldarity between, we believe it can revive Korea communities.
        4,000원
        16.
        2017.10 구독 인증기관·개인회원 무료
        This study is investigated the growth characteristics(number of available stipe, pileus diameter, pileus thickness, stipe length, stipe thickness, object weight, comparison yield ability of 1 cycle) and storage characteristics of ‘Sanjo 701’ (S7) cultivars according to relative humidity. The S7 growth characteristics were investigated by quantifying the growth and the characteristics according to the relative humidity, The storage stability was investigated every 5 days and freshness was measured by ‘Minamide Method’. S7 pileus diameter is The higher the relative humidity was confirmed becomes larger and the more increased relative humidity also increase the comparison yield ability of 1 cycle. However, pileus diameter or stipe length This could not see the big difference in the three treatment groups, the plieus thickness was no significant difference in the treatment of 80% and 95%. The fresh weight of S7 decreased significantly at 80% and 95% relative humidity after 10 days of storage, but decreased continuity in 65% humiditiry. The elongation percentage of S7 pileus was observe in 95% relative humidity, values of L, a and b (SCI), showed the highest L value in 65% and the a value in 95%. b values were similar in 65%, 80% and 95% treatments. On the ‘Minamide Method’ measure freshness was changed from the 10th day of storage at relative humidity of 95%, but humidity of 65% and 80% treatments, it changed after 15 days of storage. In this study growth characteristics and yield were increased at higher relative humidity, but storage stability was decreased. Therefore, it is deemed necessary to change the relative humidity to produce high quality mushrooms.
        17.
        2017.07 구독 인증기관·개인회원 무료
        ABSTRACT The growth of the social platform has led to a rapid increase in sustainable value cocreation activities with customers in order to know what a customer wants. In this study, we have studied about co-creation experience in social platform service. Previous prior studies have systematically classify co-creation between customer and enterprise as co-product and value-in-use, Conceptual factors. The co-creation and value-in-use factors theoretically derived from previous researches attempt to investigate the relationship between value co-creation experience and online service quality. We also tried to investigate the relationship between value co-creation experience and online service quality, customer equity, and online word of mouth. To do this, social platform services are divided into open sns and closed sns. Open SNS was targeted to Facebook, Twitter, and Pintrest users. Closed sns were targeted to Instagram, Cyworld, Band, and KakaoTalk users. In this study, it was confirmed that the relationship between online service quality, customer equity, and online word of mouth is significant through value co - creation experience. In the future, companies that design social platforms will be asked to do what they should do to co-create with customers, and provide suggestions for how to operate the platform in order to continuously activate value co-creative experiences.
        18.
        2017.06 구독 인증기관 무료, 개인회원 유료
        Metformin (1,1-dimethylbiguanide hydrochloride), derived from French lilac (Galega officinalis), is a first-line anti-diabetic drug prescribed for patients with type 2 diabetes. However, the role of metformin in odontoblastic cell differentiation is still unclear. This study therefore undertook to examine the effect of metformin on regulating odontoblast differentiation in MDPC-23 mouse odontoblastic cells derived from mouse dental papilla cells. As compared to controls, metformin significantly accelerated the mineralization, significantly increased and accelerated the expressions of ALP and Col I mRNAs, and significantly increased the accelerated expressions of DSPP and DMP-1 mRNAs, during differentiation of MDPC-23 cells. There was no alteration in cell proliferation of MDPC-23 cells, on exposure to metformin. These results suggest that the effect of metformin on MDPC-23 mouse odontoblastic cells derived from mouse dental papilla cells, facilitates the odontoblast differentiation and mineralization, without altering the cell proliferation.
        4,000원
        19.
        2017.06 구독 인증기관·개인회원 무료
        This research was relative humidity (65, 75, 85 and 95%) growth characteristics of the oak mushroom (Lentinula edodes) 'Nongjingo’. At the relative humidity was 65% in growth chamber. On this condition the moisture content of medium surface was 60.5%. That was lower than other treatments. That condition makes Pileus was 77.1% and stipe was 65%. Among the growth characteristics according to the relative humidity, the pileus diameter at 75% relative humidity were 45.5mm that largest than other treatment and pileus thickness at 75% relative humidity were largest than other treatment. The stipe thickness at 65% relative humidity were 14.8mm that lagest than other treatment. The number of available stipes at 95% relative humidity were 13.3peace/2kg that largest than other treatment. The comparison yield ability of 1 cycle was 104.2g that result in largest than other treatment at 95% relative humidity. This result was associated to the relative humidity of fruiting bodies, the lower relative humidity result in the lower of yield. However, the lower relative humidity result in the higher number of whago, Especially, at the treatment of 65% relative humidity, all the fruit bodies were produced as Whago (dry). Therefore, the higher relative humidity influenced in the higher yield but produced water mushroom. That result was thought that ‘Nongjingo’ would be possible to produce high quality mushroom by adjusting the relative humidity appropriately.
        20.
        2017.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A black nickel oxide powder, one of the commercial nickel oxide ores, was reduced by hydrogen gas in a batchtype fluidized-bed reactor in a temperature range of 350 to 500 oC and in a residence time range of 5 to 120 min. The hydrogen reduction behavior of the black nickel oxide was found to be somewhat different from that of green nickel oxide ore. For the black nickel oxide, the maximum temperature (below which nickel oxide particles can be reduced without any agglomeration) was significantly lower than that observed for the green nickel oxide. In addition, the best curve fittings of the Avrami model were obtained at higher values of the overall rate constant “k” and at lower values of the exponent “m”, compared to those values for the green nickel oxide. It may be inferred from these results that the hydrogen reduction rate of the black nickel oxide is faster than that of the green nickel oxide in the early stages, but the situation reverses in the later stages. For the black nickel oxide ore, in spite of the low temperature sintering, it was possible to achieve a high degree fluidized-bed reduction at lower temperatures and at lower gas consumption rates than was possible for the green nickel oxide. In this regard, the use of black nickel oxide is expected to yield a benefit if its ore price is sufficiently lower than that of the green nickel oxide.
        4,000원
        1 2 3