• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4477-4490
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• 2023

Fuel locking mechanisms (FLMs) are essential in upward-flow research reactors to prevent accidental fuel separation from the core during reactor operation. This study presents a novel design concept for a remotely controlled plate-type nuclear fuel locking mechanism. By employing electromagnetic field analysis, we optimized the design of the electromagnet for fuel unlocking, allowing the FLM to adapt to various research reactor core designs, minimizing installation space, and reducing maintenance efforts. Computational flow analysis quantified the drag acting on the fuel assembly caused by coolant upflow. Subsequently, we performed finite element analysis and evaluated the structural integrity of the FLM based on the ASME boiler and pressure vessel (B&PV) code, considering design loads such as dead weight and flow drag. Our findings confirm that the new FLM design provides sufficient margins to withstand the specified loads. We fabricated a prototype comprising the driving part, a simplified moving part, and a dummy fuel assembly. Through basic operational tests on the assembled components, we verified that the manufactured products meet the performance requirements. This remote-controlled micro locking mechanism holds promise in enhancing the safety and efficiency of plate-type nuclear fuel operation in upflow research reactors.

• Nuclear Engineering and Technology
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• 제45권6호
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• pp.721-730
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• 2013

Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support from AREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives, particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawal accident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (by reducing the sodium void worth). Two types of cores are being studied for the ASTRID project. The first is based on a 'large pin/small spacing wire' concept derived from the SFR V2b, while the other is based on an innovative CFV design. A distinctive feature of the CFV core is its negative sodium void worth. In 2011, the evaluation of a preliminary version (v1) of this CFV core for ASTRID underlined its potential capacity to improve the prevention of severe accidents. An improved version of the ASTRID CFV core (v2) was proposed in 2012 to comply with all the control rod withdrawal criteria, while increasing safety margins for all unprotected-loss-of-flow (ULOF) transients and improving the general design. This paper describes the CFV v2 design options and reports on the progress of the studies at the end of pre-conceptual design phase 1 concerning: - Core performance, - Intrinsic behavior during unprotected transients, - Simulation of severe accident scenarios, - Qualification requirements. The paper also specifies the open options for the materials, sub-assemblies, absorbers, and core monitoring that will continue to be studied during the conceptual design phase.

• 셀메드
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• 제10권3호
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• pp.22.1-22.7
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• 2020

Introduction: Qūbā (Tinea Corporis) is a very common disease widely prevalent worldwide. 20 - 25 % individuals suffer for this stubborn disease. Unani System of Medicine offers its treatment. There are many pharmacopoeial formulations indicated for various types of dermatophytic infections. In this study clinical efficacy and safety of the topical Unani formulation Marham Kharish Jadeed (a compound drug in the dosage form of an ointment) was assessed and compared with a standard conventional medicine. Materials and methods: A clinical study was conducted on 60 participants of qūbā randomized into test and control groups (n=30 in each group). The participants were clinically diagnosed and confirmed by microscopy of skin scrapings. The efficacy of the Unani formulation was assessed in terms of TSS score and elimination of fungal elements from the skin lesions. The data collected were analyzed statistically. Results and discussion: The study showed that the Unani formulation had comparatively better efficacy clinically than conventional medicine Terbinafine hydrochloride 1% cream in terms of reduction of itching, erythema, scaling, peripheral raised margins of the lesion comparing to baseline. In this study, 27 participants in test group and 18 participants in control group were completely cured (≥75% reduction in TSS Score with Mycological Cure) after 4 weeks of treatment. The efficacy of the Unani formulation was found significant statistically. The individual drugs of the formulations having analgesic (Musakkin), blood purifier (Muṣaffi-i-Dam), demulcent (Mulaṭṭif), antifungal (Qātil-i-fafūndῑ), detergent (Jālῑ), refrigerant (Mubarrid) and antiseptic (Dāfi'-i-'Ufūnat) properties might be responsible for the efficacy of Unani formulation. Conclusion: The findings of the study suggested that the Unani formulation was found effective and safe in the management of qūbā. No local and systemic adverse effect was reported during the study.

• 자원환경지질
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• 제51권2호
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• pp.131-147
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• 2018

본 연구에서는 중 저준위 방사성 폐기물 표층처분시설의 방사성 핵종 누출에 대한 안전성을 검증하기 위해 덮개층 및 처분고의 구조적 특성 및 물성이 고려된 유체거동 수치모사를 실시하였다. 유체거동 수치모사를 통해 시설 내 침투수거동 양상을 모사한 후, 덮개층 및 처분고 구조물 경계면을 따라 침투수 흐름 선속을 정량적으로 산정함으로써 방사성 핵종 누출의 위험성이 평가되었다. 또한 발생 가능한 시설 설계조건 및 외부 환경 변화가 고려된 다양한 시나리오 기반 수치모사를 실시함으로써 구축된 표층처분시설의 안전여유도 평가 또한 실시되었다. 그 결과, 본 연구에서 이용된 설계 구조가 표층처분시설의 안전적 운영에 적합한 것을 확인하였으며, 다양한 시나리오 기반 다중 수치모사 결과를 통해 덮개층과 처분고 수리특성의 건전성 유지 여부가 시설 안전성에 지대한 영향을 미침을 확인하였다. 특히, 처분고 콘크리트 벽체의 열화상황에서 처분고 내부로의 침투수 흐름을 관찰함으로써 처분고의 차수기능이 처분시설 안전성에 중요한 영향을 미치는 것으로 판단된다.

• 한국잡초학회지
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• 제30권1호
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• pp.1-16
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• 2010

농경지에 발생하는 주요 잡초에 대한 유묘기 검색방법을 개발하기 위하여 주요 잡초 60종에 대한 양적, 질적형질을 조사하였다. 잡초 유묘를 동정하는 형질로는 질적형질이 양적형질에 비해 보다 더 유용하였다. 자엽의 형태는 타원형과 광타원형이 가장 많았다. 차풀과 큰메꽃은 자엽의 형태가 넓은 직사각형이었다. 자엽의 형태가 횡광타원형인 초종은 4종이었다. 취명아주 등 22종의 잡초는 자엽의 형태가 1개 이상이었다. 이 중 자엽의 형태가 3가지 이상인 초종은 4종으로서 마디풀과의 참소리쟁이와 여뀌 그리고 대극과의 애기땅빈대와 깨풀이었다. 새팥은 자엽이 지면아래의 종자 속에 남아 있었다. 자엽의 엽두는 원두가 가장 많았다. 자엽의 엽저는 쐐기저가 가장 많았다. 환삼덩굴과 마디풀은 자엽의 엽저가 무엽병저였다. 일부 초종은 제 1본엽기와 제 2본엽기때 본엽의 형태가 각각 상이한 경우도 있었다. 돌콩, 새팥 및 매듭풀은 제 1본엽이 각각 광란형, 심장형, 원형 또는 광도란형이었나 제 2본엽에서는 3초종 모두 3출엽으로 전개되었다. 그리고 자귀풀과 차풀은 제 1, 2본엽의 형태가 우수우상복엽이었다. 본엽의 가장자리는 주로 전연이었으나, 큰도꼬마리를 포함한 6종은 제 1, 2본엽의 엽연이 치상거치였다. 애기땅빈대는 제 1본엽의 엽연이 전연, 제 2본엽의 엽연이 치상거치였다. 명아주과의 흰명아주와 좀명아주의 엽연은 제 1본엽기에는 전연, 제 2본엽기에는 불규칙거치였다. 잡초 유묘 자엽의 양적형질은 질적형질에 비해 종 동정 시 활용도는 떨어지나 초종에 따라서는 매우 유용한 경우도 있었다. 농경지 주요 광엽잡초 유묘에 대한 자엽 및 본엽의 질적 형질을 이용하여 간이 식별법을 제시하였다. 식법법 작성 시 자엽의 형태가 1개 이상인 잡초종에 대해서는 각각의 자엽 형태를 이용하여 종 동정이 가능하도록 하였다.

• Ocean and Polar Research
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• 제42권2호
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• pp.171-178
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• 2020

R/V EARDO, commissioned in 1992, has successfully carried out ocean research campaigns in Korean jurisdictional and adjacent waters, including continental margins and coastal zones within the Korean Exclusive Economic Zone (EEZ), for 29 years. However, it will soon be reaching the end of its useful service life. A replacement for R/V EARDO is urgently needed to ensure the safety of vessel itself and its crews, and efficient ship operation and maintenance, as well as to meet modern scientific mission requirements (SMRs). Basic specifications for a replacement ship have been devised and reviewed over the past nine months. A test of the proposed hull form was also performed. The total tonnage of the proposed vessel is approximately 740 tons, and the overall length and width are 62.0 and 11.6 m, respectively. The new ship will thus be 73% larger than the current R/V EARDO; in particular, the research workspace will be 4.4 times larger. The major design priorities are the propulsion system, efficiency of radiated noise and vibration control, and the dynamic positioning system. An environmentally friendly emission system, meeting International Maritime Organization (IMO) Tier III regulations, will be installed in the third exhaust pipe. Various wet and dry lab spaces as well as 32 different scientific instruments have also been considered in the ship design.

• 콘크리트학회논문집
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• 제13권1호
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• pp.62-68
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• 2001

본 연구는 비부착 긴장재의 응력 변화와 균열분포 구간길이에 영향을 미치는 변수에 관한 연구로서, 일반철근의 양, 긴장재양, 경간/깊이 비, 작용하중 형태 등의 변수를 중심으로 실험을 실시하였다. 실험은 일련의 기존연구를 토대로 재검증이 필요한 부분에 관하여 이루어졌다. 실험결과, 일반철근의 양과 긴장재 양은 비부착 긴장재의 응력 변화에 영향을 미치는 중요한 변수인 것으로 나타났으며, 경간/깊이 비와 작용하중의 형태는 일반철근의 양에 따라 국부적으로 비부착 긴장재의 응력 변화에 영향을 미치는 변수로서 역할을 하는 것으로 나타났다. 실험결과는 Moon/Lim의 설계식과 ACI 규준식, AASHTO LRFD 규준식, Allouche 등의 설계식에 의하여 상호 비교되었다. 그 결과, AASHTO LRFD 규준식과 Moon/Lim의 설계식이 적절하게 비부착 긴장재의 응력을 평가하고 있었다.

• 한국지진공학회논문집
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• 제3권1호
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• pp.75-92
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• 1999

본 연구에서는 현재 국내에서 면진설계를 적용하여 개발중인 KALIMER(Korea Advanced Llquid Metal Reactor) 액체금속로에 대한 내진설계 및 지진해석을 위하여 핵심구조물인 원자로구조물에 대한 단순 지진해석모델을 개발하였다 이를 이용하여 면진설계의 경우와 비면진 설계의 경우에 대한 동특성분석과 시간이력 지진해석을 수행하여 비교평가하였다. 또한 ASME 설계코드에 따른 응력한계요건을 검토하기 위하여 등가 지진응력해석을 수행하고 이로부터 내진여유도를 계산하였다 지진안전성에 대한 하나의 지표로서 원자로 구조물이 견딜수 있는 최대지진하중을 결정하기 위한 한계지진하중(Limit seismic load)을 저의하였다 지진해석결과 면진된 KALIMER 원자로구조믈은 비면진된 경우에 비하여 가속도응답과 구조물간의 상대변위응답이 현저히 감소하였고 충분한 내진여유도로 인하여 한계지진하중이 0.8g로 나타났다.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.735-744
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• 2012

In order to quantify the flow distribution characteristics of APR+ reactor, a test was performed on a test facility, ACOP ($\underline{A}$PR+ $\underline{C}$ore Flow & $\underline{P}$ressure Test Facility), having a length scale of 1/5 referring to the prototype plant. The major parameters are core inlet flow and outlet pressure distribution and sectional pressure drops along the major flow path inside reactor vessel. To preserve the flow characteristics of prototype plant, the test facility was designed based on a preservation of major flow path geometry. An Euler number is considered as primary dimensionless parameter, which is conserved with a 1/40.9 of Reynolds number scaling ratio. ACOP simplifies each fuel assembly into a hydraulic simulator having the same axial flow resistance and lateral cross flow characteristics. In order to supply boundary condition to estimate thermal margins of the reactor, the distribution of inlet core flow and core exit pressure were measured in each of 257 fuel assembly simulators. In total, 584 points of static pressure and differential pressures were measured with a limited number of differential pressure transmitters by developing a sequential operation system of valves. In the current study, reactor flow characteristics under the balanced four-cold leg flow conditions at each of the cold legs were quantified, which is a part of the test matrix composing the APR+ flow distribution test program. The final identification of the reactor flow distribution was obtained by ensemble averaging 15 independent test data. The details of the design of the test facility, experiment, and data analysis are included in the current paper.

• 대한두경부종양학회지
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• 제29권2호
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• pp.48-50
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• 2013

Angiomyoma is a rare, benign smooth muscle cell tumor. These tumors may be found anywhere in the body. They frequently occur in the lower extremities except venous type. Angiomyoma in the head and neck area is very rare, and only a few cases have been reported. A 63 year-old male patient visited to outpatient clinic due to size-growing nodule-like lesion in the Lt. alar area. Excisional biopsy was done for diagnosis. The lesion was totally excised with 2 mm safety margin. Frozen biopsy of the lesion was requested, and all resection margins were proved negative. To cover the raw surface, full thickness skin grafting was performed. The graft was harvested from Rt. posterior auricular area. Tie over dressing was applyed on Lt. alar area. The graft was well taken and healed without any complication in both short term and long term follow up periods of 2 weeks, 1 month, 2 months, and 6 months. Donor site completed healed without any complications. The leiomyoma is benign tumor originated from smooth muscle, and it can be classified into solid leiomyoma, angiomyoma, and epithelioid leiomyoma. Especially, the angiomyoma consists of smooth muscle cell and blood vessel, and it is originated from the tunica media of blood vessel. Angiomyoma alone frequently occurs in the lower extremities as solitary painless subcutaneous tumor. Venous type of angiomyoma in the oral cavity was reported in other references, but on the facial surface it may be the first case reported as paper. So this report can be very meaningful.