• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4049-4061
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• 2022

TRISO-coated particle fuel is widely used in high temperature gas cooled reactors and other advanced reactors. The performance of coated fuel particle is one of the fundamental bases of reactor safety. The failure probability of coated fuel particle should be evaluated and determined through suitable fuel performance models and methods during normal and accident condition. In order to better facilitate the design of coated particle fuel, a new TRISO fuel performance code named FRAT (Fission product Release Analysis Tool) was developed. FRAT is designed to calculate internal gas pressure, mechanical stress and failure probability of a coated fuel particle. In this paper, FRAT was introduced and benchmarked against IAEA CRP-6 benchmark cases for coated particle failure analysis. FRAT's results agree well with benchmark values, showing the correctness and satisfactory applicability. This work helps to provide a foundation for the credible application of FRAT.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1350-1364
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• 2023

2D/1D coupling method is an important neutron transport calculation method due to its high accuracy and relatively low computation cost. However, 2D/1D coupling method may diverge especially in small axial mesh size. To analyze the convergence behavior of 2D/1D coupling method, a Fourier analysis for k-eigenvalue neutron transport problems is implemented. The analysis results present the divergence problem of 2D/1D coupling method in small axial mesh size. Several common attempts are made to solve the divergence problem, which are to increase the number of inner iterations of the 2D or 1D calculation, and two times 1D calculations per outer iteration. However, these attempts only could improve the convergence rate but cannot deal with the divergence problem of 2D/1D coupling method thoroughly. Moreover, the choice of axial solvers, such as DGFEM SN and traditional SN, and its effect on the convergence behavior are also discussed. The results show that the choice of axial solver is a key point for the convergence of 2D/1D method. The DGFEM SN based 2D/1D method could converge within a wide range of optical thickness region, which is superior to that of traditional SN method.

• 실천공학교육논문지
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• 제14권1호
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• pp.195-203
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• 2022

최근 스마트공장 도입이 확산됨에 따라 스마트공장 도입에 대한 긍정적, 부정적 영향에 대한 관심과 연구가 증가하고 있다. 본 연구에서는 750개 기업을 대상으로 일터혁신지수 하위 4개 부문(노사관계, 인적자원관리, 인적자원개발, 작업조직)별로 스마트공장 도입에 따른 일터혁신지수의 변화를 정량적으로 분석하였다. 전반적으로 스마트공장을 도입한 기업의 일터혁신지수가 그렇지 않은 경우보다 높게(0.5~9.4점) 나타났으며 특히 작업조직부분에서는 통계적으로 유의미한 차이를 보였다. 또한 스마트공장 도입과 일터혁신 컨설팅의 영향을 함께 분석한 결과, 노사관계부문과 작업조직부문의 경우 스마트공장을 도입하고 컨설팅을 받은 것이 일터혁신지수 향상에 부합하는 결과를 보였다.

• 공학교육연구
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• 제16권3호
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• pp.79-86
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• 2013

The purpose of this study was to analyze the factors related to the satisfaction of the introductory engineering education program for the employees, who majored liberal arts or commerce, among the educational programs for industrial workers which are performed as an effort to spread the performance of the Innovation Center for Engineering Education, and reinforce the competitiveness through effective program operation. This study was performed on the basis of CIPP evaluation model (context, input, process, product). A factorial analysis and a regression analysis were conducted based on a survey made on 87 persons who completed the introductory engineering education program among the employees of D group who majored liberal arts or commerce. It is expected that this study will contribute toward suggesting the implications for designing and operating the educational programs for industrial workers in order to find out the important factors of satisfaction and to conduct the education operation with professionalism.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1970-1977
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• 2019

Understanding the irradiation hardening effect of structural steels under various irradiation conditions plays an important role in developing advanced nuclear systems. Such being the case, a crystal plasticity model for body-centered cubic (BCC) crystal based on the density of dislocations and irradiation defects is summarized and numerically implemented in this paper. Based on this model, nano-indentation hardness of Chinese A508-3 steels with ion irradiation is calculated. Very good agreement is observed between simulation and experimental data of several different irradiation doses subjected to various operating temperatures, from which, it can be concluded that indentation hardness increases with increasing irradiation dose at both room temperature and high temperature. Consequently, the validity of this model has been proved properly, and furthermore, the model established in this paper could guide the study of irradiation hardening effect and temperature effect to some extent.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1416-1428
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• 2021

Pebble flow characteristics can be significantly affected by the configuration of pebble bed, especially for HTGR pebble beds. How to achieve a desired uniform flow pattern without stagnation is the top priority for reactor design. Pebbles flows inside some specially designed pebble bed with arc-shaped contraction configurations at the bottom, including both concave-inward and convex-outward shapes are explored based on discrete element method. Flow characteristics including pebble retention, residence-time frequency density, flow uniformity as well as axial velocity are investigated. The results show that the traditionally designed pebble bed with cone-shape bottom is not the most preferred structure with respect to flow pattern for reactor design. By improving the contraction configuration, the flow performance can be significantly enhanced. The flow in the convex-shape configuration featured by uniformity, consistency and less stagnation, is much more desirable for pebble bed design. In contrast, when the shape is from convex-forward to concave-inward, the flow shows more nonuniformity and stagnation in the corner although the average cross-section axial velocity is the largest due to the dominant middle pebbles.

• Electronic Materials Letters
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• 제14권6호
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• pp.718-724
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• 2018

With the development of photovoltaic industry, the cost of photovoltaic power generation has become the significant issue. And the metallization process has decided the cost of original materials and photovoltaic efficiency of the solar cells. Nowadays, double printing process has been introduced instead of one-step printing process for front contact of polycrystalline silicon solar cells, which can effectively improve the photovoltaic conversion efficiency of silicon solar cells. Here, the relative cheap Cu paste has replaced the expensive Ag paste to form Ag/Cu composite front contact of silicon solar cells. The photovoltaic performance and the cost of photovoltaic power generation have been investigated. With the optimization on structure and height of Cu finger layer for Ag/Cu composite double-printed front contact, the silicon solar cells have exhibited a photovoltaic conversion efficiency of 18.41%, which has reduced 3.42 cent per Watt for the cost of photovoltaic power generation.

• Earthquakes and Structures
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• 제9권5호
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• pp.1029-1044
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• 2015

To investigate the seismic pounding response of long-span bridges with high-piers under strong ground motions, shaking table tests were performed on a 1/10-scaled bridge model consisting of three continuous spans with rigid frames and one simply-supported span. The seismic pounding responses of this bridge model under different earthquake excitations including the uniform excitation and the traveling wave excitations were experimentally studied. The influence of dampers to the seismic pounding effects at the expansion joints was analyzed through nonlinear dynamic analyses in this research. The seismic pounding effects obtained from numerical analyses of the bridge model are in favorable agreement with the experimental results. Seismic pounding effect of bridge superstructures is dependent on the structural dynamic properties of the adjacent spans and characteristics of ground motions. Moreover, supplemental damping can effectively mitigate pounding effects of the bridge superstructures, and reduce the base shear forces of the bridge piers.

• 공학교육연구
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• 제16권1호
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• pp.64-74
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• 2013

This study investigated the effect of engineering education accreditation on employment rate at the University of Seoul. The graduates who had been educated in the accredited program showed higher grade point average (GPA) and higher employment rate (89.0%) than the graduates who had been educated in the program without the accreditation (70.9%). The employment rate of all graduates increased with increasing GPA, the mathematics-science-computer (MSC) credit acquired, design credit acquired, and the number of interviews with supervising professors. Theses results showed that the MSC and design subjects and the counselling are at least beneficial in getting a job for students at the University of Seoul. When GPA, design credit acquired, and the number of counselling are the same, graduates with the engineering education accreditation showed much higher employment rate than the graduates without the accreditation. These preliminary results suggest that the engineering education programs with accreditation at the University of Seoul are beneficial for students in getting a gob through motivating them to acquire more credits in design subjects, doing greater number of counselling with supervising professors, and making better academic achievement. In addition, the engineering education accreditation at the University of Seoul helped students developing their personal skills such as team workability, communication skills, and creativity via carrying out design subjects, which may affect the employment rate indirectly.

• 공학교육연구
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• 제13권6호
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• pp.57-71
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• 2010

본 연구는 대학교육을 통하여 획득해야 하는 핵심역량들을 추출하여 공과대학 신입생들이 인식하는 현재의 역량수준과 기대하는 역량수준을 조사하고 공과대학 교육의 방향성을 탐색해 보고자 하는데 목적이 있다. 핵심역량에 대한 문헌분석을 통해서, '전공능력', '교양능력', '외국어능력', '기초수학능력', '인간소통능력'의 5가지를 공학교육의 목표와 내용이 되어야 할 핵심 역량으로 추출하였다. 이를 연구도구화 한 뒤, C대학교 공과대학 신입생 584명을 대상으로 핵심역량에 대한 현재인식수준과 기대인식수준을 조사 연구하였다. 연구 결과, 첫째, 신입생들은 모든 역량에서 현재 역량수준이 낮다고 인식하고 있었으며, 특히 '외국어 역량'에 대한 인식수준이 가장 낮았다. 기대인식수준에 대한 교육요구도 '외국어능력'이 가장 높았고, '전공능력'은 두 번째로 높았다. 둘째, 신입생들의 하위특성을 성별, 고등학교 계열별, 출신고등학교의 지역별, 대학입학전형 유형별, 수능 수리유형별로 차이검증을 실시한 결과, 하위특성별로 현재인식수준과 기대인식수준간에 유의미한 차이가 있었다. 연구결과를 토대로, 본 연구는 공과대학 교육의 방향으로 외국어(영어)교육의 강화, 학습자의 하위 특성에 따른 개인차 해소를 위한 다양한 교육프로그램 설계 및 실행, 전공능력뿐 아니라 교양능력 및 인간소통능력의 중요성에 대한 인식 제고와 관련 프로그램의 강화, 교수-학습과정에 대한 피드백 자료 축적을 통한 공학 교육프로그램의 지속적인 수정 보완작업, 공학교육과정과 특별프로그램을 통한 진로교육의 활성화를 제언하였다.