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        검색결과 494

        21.
        2023.11 구독 인증기관·개인회원 무료
        Concentrated effluent and spent ion exchange resins (IERs) from nuclear power plants (NPPs) were generated prior to the establishment of a disposal facility site and waste acceptance criteria have been temporarily stored at the NPPs because their suitability for disposal has not been confirmed. In particular, at the Kori Unit 1, which was the first to start the commercial operation in South Korea, the initially generated concentrated effluent and IERs are repackaged in large size of concrete containers and stored without provided regulation standard. The concentrated effluent is package as cementitious form in 200 L drums and repackaged in concrete containers, case of the IERs were solidified or dehydrated and repackaged in round concrete container. In this study, we review and propose a disposal plan for concentrated effluent and IERs repackaging drums that have not been confirmed to be suitable for disposal from the first operating nuclear power plant, Kori Unit 1, 2. First, the concentrated effluent was stored in four 200 L drums respectively, and then, it was again stored in concrete container and which was poured on top using grouted concrete. Therefore, the process was required by cutting concrete container for extracting the internal drums at first. Internal radioactive waste should be crushed to the suitable waste criteria and solidified, finally disposal in to the polymer concrete high integrity container (PC-HIC). IER was repackaged and disposal in square type of 200 L concrete drums respectively covered the cap. So, extracting the internal drums should be extracted after removing the cap of external concrete container. Cement solidification drums can be crushed and re-solidified or disposed in the PC-HIC. Stored IER after dehydrated can be disposal in PC-HIC. In conclusion, the container was used as a package that repackaging the concentrated effluent and IER was separated into two different types of waste depending on the level of contamination of radioactivity, the polluted area is disposed of as radioactivity contamination or the unspoiled area will be treated as self-disposal waste.
        22.
        2023.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This paper described a method for analyzing the structural performance of a metal container used for disposing radioactive waste generated during the decommissioning of a nuclear power plant, and numerical analysis results of a method for reinforcing the container. The containers to be analyzed were those that can be used in near-surface and landfill disposal facilities scheduled to be operated at the Gyeongju radioactive waste disposal facility. Structural reinforcement of the container was performed by lattice reinforcement, column reinforcement, and bottom plate reinforcement. Accordingly, a total of 14 reinforcement cases were modeled. The external force causing damage to the container was set equivalent to the impact of a 9-m fall, accounting for the height of the vault at the near-surface disposal facility. The reinforcement methods with a high contribution to the structural performance of the container were concluded to be lattice and column reinforcements.
        5,100원
        23.
        2023.05 구독 인증기관·개인회원 무료
        Licensing for the application of the Polymer Concrete High Integrity Container (PC-HIC) to nuclear power plants has been completed or is in progress. Approval for the expanded application to all domestic nuclear power plants has been completed to utilize the 860 L PC-HICs for the 2nd stage surface repository, and the regulatory body is reviewing the license application to use the 510 L PCHICs for the 1st stage underground repository in the representative nuclear power plants. The 860 L PC-HICs, which have been licensed for all domestic nuclear power plants, will be used for safe storage management and disposal of low-dose dried concentrate waste and spent resin, and a total of 100 units is expected to be supplied to representative nuclear power plants that have been licensed first. The 510 L PC-HICs are planned to be used for underground disposal of high-dose spent resin and dried concentrate waste. Prior to the application of PC-HICs to nuclear power plants and disposal to the repository, it is necessary to establish realistic and reasonable requirements through close consultations between waste generator and disposal operators to ensure the suitability for disposal of PC-HIC packages and to carry out disposal delivery and acceptance work. Since the Polymer Concrete High Integrity Container (PC-HIC) has long-term integrity of more than 300 years and the barrier does not temporarily collapse, spent resin and dried concentrate waste, which are radioactive wastes to be solidified, can be disposed of much more safely in PC-HIC packages than solidified types. Acceptance criteria for the PC-HIC packages should be prepared fully reflecting the advantages of PC-HIC, and quality assurance methods for physical/chemical/radiological characterization results based on the Waste Certification Program (WCP) should be supported. In addition, infrastructure should be secured for safe transportation, handling, and storage of the PC-HIC packages. In this paper, we have tried to find a reasonable acceptance criteria, quality assurance method, and infrastructure level according to the dose and disposal conditions of PC-HIC packages.
        24.
        2023.05 구독 인증기관·개인회원 무료
        Currently, KHNP-CRI has developed 100 kW plasma torch melting facility to reduce the amount of radioactive waste in nuclear power plant. Plasma torch melting technology uses electric arc phenomena like lightning to melt the target material at a high temperature of about 1,600°C. The technology is applicable to treatment for various types of waste such as combustible, non-combustible and mixed wastes. The volume reduction ratio by the technology is respectively expected to be about 1/60 of combustible wastes and about 1/5 for non-combustible wastes. It is important to discharge the melt without problems in the melting technology. In general, molten slag has properties such as high viscosity and quick solidification. Because of the properties, when discharging into slag container, the final product is accumulated like a mountain. To improve this problem, there is three suggestions; 1) rotation of the slag container, 2) vibration of the slag container, and 3) heating of the slag container.
        25.
        2023.05 구독 인증기관·개인회원 무료
        In case of damaged spent fuels, it would require additional treatment for their transportation and storage to capture the radioactive fission products in a defined space. The canning container for the damaged spent fuels is one way to seal the radioactive fission products inside the container. In the Post Irradiation Examination Facility (PIEF) of KAERI, the Quiver container has been introduced for canning damaged spent fuels from Westinghouse Sweden. The main container body has been manufactured for particle-tightness of spent fuel. In addition, drying equipment is being prepared for gas-tightness of spent fuel. The drying equipment can remove water and fill the inert gas inside the container. Before drying inside the container, we evaluated the volatile fission products inventory because volatile fission products could be released during the drying process. Despite assuming highly conservative hypotheses for the inventory remaining in damaged fuel rods, the amount that could be released during the drying process was less and dose rate levels around the evacuation piping system were low.
        26.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        코로나 19 팬데믹 및 기후 변화 등으로 전 세계적으로 필수적인 생필품과 자원의 품귀 이슈가 지속해서 발생하고 있다. 이러한 현상을 극복하고자 교역량의 수요가 갑자기 증가하였으며 이 결과 컨테이너선의 운임이 대폭 상승하였다. 컨테이너선의 크기 변화는 1960 년대 1,500TEU(twenty-foot equivalent unit)를 시작으로 2021년에는 24,400TEU로 대형화가 진행되고 있다. 컨테이너 적재 능력의 향상은 라싱브 릿지 구조의 대형화와 긴밀하게 연관되어 있고, 안전한 컨테이너 고박 및 항해 시 발생하는 다양한 외력 하중에 안전한 구조설계를 해야 한다. 현재 주요 선급에서는 라싱브릿지 구조 안전성을 평가할 수 있는 구조해석 기반의 지침서를 배포하고 있으나, 허용기준 및 평가 방 법이 달라서 설계 시 엔지니어들에게 혼선을 주고 있다. 본 연구에서는 결과에 영향을 줄 가능성이 큰 주요 변수들(모델링 범위, 오프닝 고 려 여부, 메쉬 크기) 변화에 따른 강도 변화 특성을 정리하였다. 이 결과를 바탕으로 저자들은 합리적인 구조해석 기반 평가에 대한 검토사 항을 제안하였고, 추후 선급 기준 개정 시 참고가 될 수 있을 것으로 기대한다.
        4,000원
        27.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 후박나무 용기묘를 대상으로 전광, 35%, 55%, 75% 차광수준에 따른 생장 특성 및 생리적 반응을 알아보고자 실시하였다. 후박나무 묘목은 차광 시 상대적으로 지상부의 생장특성을 보여주는 지표들이 높은 경향을 보였으며, 전광에서는 뿌리와 관련된 지표인 뿌리건중비, 뿌리생장에 서 유의적으로 높은 경향을 보였다. 또한, 전광에서의 낮은 광보상점과 높은 순양자수율은 이미 후박나무가 내음성을 가지고 있고, 광이 부족한 환경에 노출된 차광처리구들에서 암호흡량의 감소, PIABS 및 SFIABS의 증가로 광합성 기구의 활력을 효율적으로 증가시키는 것을 알 수 있다. 한편, 전광은 지상부 비율의 증가, 낮은 T/R율과 가장 높은 순광합성속도를 보여 광합성으로 합성되는 탄수화물이 지상부 뿐만 아니라 지하부의 생장 역시 증가시킨 것을 알 수 있는 결과였다. 따라서 후박나무 용기묘는 전광조건에서 생장 및 생리적 특성이 가장 양호한 경향을 보였다.
        4,200원
        28.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 헛개나무 용기묘를 생산하기 위한 적정 차광수준을 밝히고자 수행되었다. 헛개나무 1년생 용기묘를 대상으로 4가지 차광처리(0%, 35%, 55%, 75%)에 따른 용기묘의 간장, 근원경, 건중량, 묘목품질지수, 엽록소 함량 등의 반응 특성을 조사하였다. 연구 결과, 헛개나무 용기묘의 근원경, 잎 건중량, 뿌리 건중량은 차광처리구 간에 통계적인 유의성이 나타나지 않았으나(p≥0.05), 간장, 줄기 건중량, 엽록소 함량은 차광처리에 의해 55%와 75%의 차광처리에서 유의적인 차이를 나타내며 증가하였다(p<0.001). 간장과 줄기 건중량의 증가로 헛개나무 용기묘의 H/D율과 T/R율은 증가하였으며 묘목품질지수는 낮게 나타났다. 따라서, 헛개나무 1년생 용기묘 생산을 위한 적절한 차광수준은 묘목품질지수가 가장 높게 나타난 35%로 판단된다. 본 연구결과는 우량한 헛개나무 용기묘 생산을 위한 기초자료로 활용될 수 있을 것으로 기대된다.
        4,000원
        29.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The recent increase in earthquake activities has highlighted the importance of seismic performance evaluation for civil infrastructures. In particular, the container crane essential to maintaining the national logistics system with port operation requires an exact evaluation of its seismic response. Thus, this study aims to assess the seismic vulnerability of container cranes considering their seismic characteristics. The seismic response of the container crane should account for the structural members’ yielding and buckling, as well as the crane wheel’s uplifting derailment in operation. The crane’s yielding and buckling limit states were defined using the stress of crane members based on the load and displacement curve obtained from nonlinear static analysis. The derailment limit state was based on the height of the rail, and nonlinear dynamic analysis was performed to obtain the seismic fragility curves considering defined limit states and seismic characteristics. The yield and derailment probabilities of the crane in the near-fault ground motion were approximately 1.5 to 4.7 and 2.8 to 6.8 times higher, respectively, than those in the far-fault ground motion.
        4,000원
        30.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper introduces a container loading problem and proposes a theoretical approach that efficiently solves it. The problem is to determine a proper weight of products loaded on a container that is delivered by third party logistics (3PL) providers. When the company pre-loads products into a container, typically one or two days in advance of its delivery date, various truck weights of 3PL providers and unpredictability of the randomness make it difficult for the company to meet the total weight regulation. Such a randomness is mainly due to physical difference of trucks, fuel level, and personalized equipment/belongings, etc. This paper provides a theoretical methodology that uses historical shipping data to deal with the randomness. The problem is formulated as a stochastic optimization where the truck randomness is reflected by a theoretical distribution. The data analytics solution of the problem is derived, which can be easily applied in practice. Experiments using practical data reveal that the suggested approach results in a significant cost reduction, compared to a simple average heuristic method. This study provides new aspects of the container loading problem and the efficient solving approach, which can be widely applied in diverse industries using 3PL providers.
        4,000원
        33.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 컨테이너 재배용 중간목의 노지 생산기술 개발을 위하여 왕벚나무 3년생을 대상으로 전정, 시비종류·시비량 처리에 미치는 영향을 구명하기 위해 수행되었다. 노지에 정식 후 전정 유무(1.8m 이하 전정(P) 및 무전정(N.P))와 시비종류 및 시비량(유박비료 21.7, 43.3g/㎡/yr, 퇴비 1.0, 2.0 ㎏/tree/yr, 고형비료 40.5, 81.0g/㎡/yr)을 대조구를 포함하여 처리하였다. 묘목의 생장에 미치는 영향을 평가하기 위해 정식 2년 후 생장 및 상대생장량, 건물생산량, 품질지수 및 양분특성을 비교‧분석하였다. 묘고 및 근원경 상대생장량은 무전정 처리보다 전정처리에서 유의적(p≤0.000)으로 높았으며, 전정을 실시한 고형비료 81.0g/㎡/yr 처리에서 가장 높은 생장량을 보였다. 본 연구결과 왕벚나무 접목 3년생을 노지에 정식한 후, 1.8m 이하 전정을 실시하고 고형비료 81.0g/㎡/yr을 처리하여 2년 재배 시, 고품질의 컨테이너 재배용 왕벚나무 중간목이 생산되는 것으로 판단된다.
        4,300원
        34.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 전장이 400m인 24,000TEU급 컨테이너선박을 대상으로 선박 내 빌지펌핑의 성능에 대한 케이스 스터디를 수행하 였다. 본 연구의 대상인 24,000TEU급 컨테이너선박의 빌지시스템의 경우 선급의 규칙에 맞게 설계되었지만, 선박 내 설치되어 있는 빌지펌 프의 정격유량 및 최대유량 조건에서도 SOLAS Reg.II-1/35-1의 2 m/s 요건을 만족시키지 못하였다. 특히 1번 ~ 4번 화물창에 대해, 해수로 가득차 있다고 가정한 상태에서 해수를 모두 배출하는 동안에 빌지 주관에서의 평균유속을 계산할 결과, 2번 화물창, 3번 화물창 및 4번 화물창은 평균유속이 2 m/s 미만으로 기준에 적합하지 않은 것으로 나타났다. 본 연구에서는 이를 해결하기 위해 2번, 3번 및 4번 화물창의 150A 빌지 지관을 200A 배관으로 교체하여 계산을 수행하였으며, 그 결과 화물창 내의 해수를 모두 배출하는 동안의 빌지 주관에서의 해 수평균유속이 각각 2.479m/s , 2.476,m/s 및 2.459m/s 로 기준을 만족시키는 것을 알 수 있었다.
        4,000원
        35.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Test of the operating characteristics and energy saving performance of a container cooling system that reduces the operating energy of a refrigeration system using a loop thermosyphon heat exchanger that removes heat by temperature difference between outdoor and indoor was performed. As a result of the experiments, when the loop thermosyphon and the refrigeration system were operated simultaneously, the refrigeration system operated intermittently by reducing the heat load. As the temperature difference between indoor and outdoor increased, the operating time of the refrigeration system decreased and the energy efficiency rate increased. Energy efficiency rate showed a tendency to increase with increasing temperature difference, and the predicted correlation of energy efficiency rate using the performance of the loop thermosyphon heat exchanger and the refrigeration system was relatively consistent with the experimental value.
        4,000원
        36.
        2022.10 구독 인증기관·개인회원 무료
        High Integrity Container (HIC) made of polymer concrete was developed for the efficient treatment and safe disposal of radioactive spent resin and concentrate waste in consideration of the disposal requirements of domestic disposal sites. Permission for application of Polymer Concrete High Integrity Container (PC-HIC) to the domestic nuclear power plants (NPPs) has been completed or is under examination by the regulatory agency. In the case of 860 L PC-HIC for very-low-level-waste (VLLW) or low low-level-waste (LLW), the application of four representative NPPs has been approved, and the license for extended application to the rest NPPs is also almost completed. A licensing review is also underway to apply 510 L PC-HIC for intermediate and low-level-waste (ILLW) to representative nuclear power plants. In order to handle and efficiently store and manage PC-HICs and high-dose PCHIC packages, a gripper device that can be remotely operated and has excellent safety is essential, and the introduction of NPPs is urgent. The conventional gripper device developed by the PC-HIC manufacturer for lifting test to evaluate the structural integrity of PC-HIC requires a rather wide storage interval due to its design features, and does not have a passive safety design to handle heavy materials safely. In addition, work convenience needs to be reinforced for safety management of high radiation work. Therefore, we developed a conceptual design for a gripper device with a new concept to minimize the work space by reflecting on-site opinions on the handling and storage management conditions of radioactive waste in NPPs, and to enhances work safety with the passive safety design by the weight of the package and the function of checking the normal seating of the device and the normal operation of the grip by the detector/indicator, and to greatly improves the work efficiency and convenience with the wireless power supply function by rechargeable battery and the remote control function by camera and wireless monitoring & control system. Through design review by experts in mechanical system, power supply and instrumentation & control fields and further investigations on the usage conditions of PC-HICs, it is planned to facilitate preparations for the application of PC-HIC to domestic NPPs by securing the technical basis for a gripper device that can be used safely and efficiently and seeking ways to introduce it in a timely manner.
        37.
        2022.10 구독 인증기관·개인회원 무료
        The Deep Borehole Disposal (DBD) method has various advantages, such as minimizing the use of site area and corrosion of the disposal container and improving long-term structural safety. However, it is necessary to review the problems that may occur in various technologies related to the emplacement and retrieval of the disposal container and the sealing of the borehole. Therefore, the purpose of this study is to evaluate the structural integrity of an emplacement and retrieval device (hereinafter, the disposal container connecting device) of a DBD container. The disposal connecting device was evaluated according to ANSI 14.6 and NUREG-0612 standards. The allowable stress should be less than the yield strength under the load condition of 3g. The length of the disposal container connecting device was about 2,900 mm, the diameter was 406 mm, and the weight was about 1.2 tons. In addition, 10 disposal containers weighing up to 2.2 tons were handled. The disposal container connecting device was made of stainless steel, and the maximum operating temperature was about 300°C. For structural evaluation, ABAQUS finite element analysis program was used. The analysis model was modeled only 1/2 part considering symmetry condition. The analysis model was modeled using 410,431 nodes and 344,119 solid elements. Three times load was applied to the weight of the disposal container. Axisymmetric conditions were applied to the symmetrical surface of the disposal container, and vertical restraints were applied to the upper lifting lugs. A surface-to-surface contact condition was applied to the part where the contact occurred. As a result of the analysis, the greatest stress was generated at the part supported by the clamp at the disposal container connector at 168.9 MPa. In the lugs and pins connecting the guide and the connecting device, a stress of 530.1 MPa was generated by shearing. In the bolts of the disposal container connecting device, a stress of 498MPa was generated and the safety margin was 1.73. A stress of 486.1 MPa was generated in the disposal container connecting device, and the safety margin was the smallest 1.16. As a result of the analysis, all components of the disposal container connecting device showed a safety margin of 1.16 or more at the maximum operating temperature and satisfied the allowable stress.
        38.
        2022.10 구독 인증기관·개인회원 무료
        Currently, the most widely accepted disposal concept for long-term isolation of high level radioactive waste including spent nuclear fuels is to disposal in a deep geological repository designed and constructed with multiple barriers composed of engineered and natural barriers so that the waste can be completely isolated in a stable deep geological environment. In this concept, an important consideration is the heat generated from the waste due to the large amount of fission products present in the high level waste loaded in the disposal container. For safe and complete isolation of high level radioactive waste in the deep geology, the disposal concepts that meet the thermal requirements for the disposal system design have been developed by harmonizing the thermal characteristics of engineered and natural barriers in Korea. In this paper, the deposition hole configuration and the decay heat dissipation area (surface area) of disposal container were considered for the efficient thermal management in the deep geological disposal concept. Heat transfer through the waste form, its container and surrounding components and the rock will be mainly by conduction. Heat transfer by radiation and convection can be negligible after backfilling. When considering heat conduction, according to Fourier’s law, if the thermal conductivity of the repository components is the same, the greater the heat dissipation area and the adjacent temperature gradient, the greater the conduction effect. Therefore, rather than the conventional concept of loading 4 PWR spent fuel assemblies per disposal container and placing one disposal container in a deposition hole, it is better to load one assembly per disposal container and place 4 disposal containers in a deposition hole. In this case, it was found that the disposal area could be reduced through efficient thermal management. Considering this thermal management method as an alternative to the concept of deep geological disposal, additional research is needed.
        40.
        2022.06 구독 인증기관 무료, 개인회원 유료
        To reduce the air pollution from maritime activities, which is proven to have severe impacts on the worldwide environment and human health, many international regulations have been established. Therefore, an effective political strategy and a complete inventory of emissions are needed to control atmospheric ship pollution and comply with these international standards. The purpose of this study is to calculate the amount of emission in three operating modes (cruising, maneuvering, and hoteling) for some main pollutants emitted from container ships and trucks operating in Daesan port in Korea based on bottom-up methodology. The results showed that the volume of air pollution of about 6,500 tons from container ships and 1,455 tons from container trucks were emitted in Daesan port area. Also, a total of 4 billion won (about 3.6 billion won from container ships, and about 400 million won from container trucks) was estimated.
        4,000원
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