• Title/Summary/Keyword: Energy & fuel technology

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Technology Trends of Fuel Cell Power Plant Based on Biogas Fuel (바이오가스 연료기반 연료전지발전 기술동향)

  • Lee, Jong-Gyu;Jeon, Jae-Ho;Lee, Jong-Yeon
    • New & Renewable Energy
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    • v.4 no.3
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    • pp.5-14
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    • 2008
  • The target for the reduction of $CO_2$ emissions, as specified in the Kyoto Protocol, can only be achieved by an extended use of renewable fuels and the increasing of the energy efficiency. The energy generation from waste gases with a reasonable content of methane like biogas can significantly contribute to reach this target. A further reduction of greenhouse gas emissions is possible by increasing the electrical efficiency using progressive technologies. Fuel cells can be highly energy conversion devices. Utilizing biogas as the fuel for fuel cell systems offers an option that is technically feasible, potentially economically attractive and greenhouse gas neutral. High temperature fuel cells that are able to operate with carbon monoxide in the feed are well suited to these applications. Furthermore, because they do not require noble metal catalysts, the cost of high-temperature fuel cells has the greatest potential to become competitive in the near future compared to other types of fuel cells.

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A Thermal Conductivity Model for LWR MOX Fuel and Its Verification Using In-pile Data

  • Byung-Ho Lee;Yang-Hyun Koo;Jin-Silk Cheon;Je-Yong Oh;Hyung-Koo Joo;Dong-Seong Sohn
    • Nuclear Engineering and Technology
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    • v.34 no.5
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    • pp.482-493
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    • 2002
  • The MOX fuel for LWR is fabricated either by direct mechanical blending of UO$_2$ and PuO$_2$ or by two stage mixing. Hence Pu-rich particles, whose Pu concentrations are higher than pellet average one and whose size distribution depends on a specific fabrication method, are inevitably dispersed in MOX pellet. Due to the inhomogeneous microstructure of MOX fuel, the thermal conductivity of LWR MOX fuel scatters from 80 to 100 % of UO$_2$ fuel. This paper describes a mechanistic thermal conductivity model for MOX fuel by considering this inhomogeneous microstructure and presents an explanation for the wide scattering of measured MOX fuel's thermal conductivity. The developed model has been incorporated into a KAERI's fuel performance code, COSMOS, and then evaluated using the measured in-pile data for MOX fuel. The database used for verification consists of homogeneous MOX fuel at beginning-of-life and inhomogeneous MOX fuel at high turnup. The COSMOS code predicts the thermal behavior of MOX fuel well except for the irradiation test accompanying substantial fission gas release. The over-prediction with substantial fission gas release seems to suggest the need for the introduction of a recovery factor to a term that considers the burnup effect on thermal conductivity.

Recent Activities of Solid Oxide Fuel Cell Research in the 3D Printing Processes (3D 프린팅 공정을 이용한 고체 산화물 연료전지 연구 동향)

  • MASAUD, ZUBAIR;KHAN, MUHAMMAD ZUBAIR;HUSSAIN, AMJAD;ISHFAQ, HAFIZ AHMAD;SONG, RAK-HYUN;LEE, SEUNG-BOK;JOH, DONG WOO;LIM, TAK-HYOUNG
    • Transactions of the Korean hydrogen and new energy society
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    • v.32 no.1
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    • pp.11-40
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    • 2021
  • Solid oxide fuel cell (SOFC) has received significant attention recently because of its potential for the clean and efficient power generation. The current manufacturing processes for the SOFC components are somehow complex and expensive, therefore, new and innovative techniques are necessary to provide a great deal of cell performance and fabricability. Three-dimensional (3D) printing processes have the potential to provide a solution to all these problems. This study reviews the literature for manufacturing the SOFC components using 3D printing processes. The technical aspects for fabrication of SOFC components, 3D printing processes optimization and material characterizations are discussed. Comparison of the SOFC components fabricated by 3D printing to those manufactured by conventional ceramic processes is highlighted. Further advancements in the 3D printing of the SOFC components can be a step closer to the cost reduction and commercialization of this technology.

Statistical model for forecasting uranium prices to estimate the nuclear fuel cycle cost

  • Kim, Sungki;Ko, Wonil;Nam, Hyoon;Kim, Chulmin;Chung, Yanghon;Bang, Sungsig
    • Nuclear Engineering and Technology
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    • v.49 no.5
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    • pp.1063-1070
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    • 2017
  • This paper presents a method for forecasting future uranium prices that is used as input data to calculate the uranium cost, which is a rational key cost driver of the nuclear fuel cycle cost. In other words, the statistical autoregressive integrated moving average (ARIMA) model and existing engineering cost estimation method, the so-called escalation rate model, were subjected to a comparative analysis. When the uranium price was forecasted in 2015, the margin of error of the ARIMA model forecasting was calculated and found to be 5.4%, whereas the escalation rate model was found to have a margin of error of 7.32%. Thus, it was verified that the ARIMA model is more suitable than the escalation rate model at decreasing uncertainty in nuclear fuel cycle cost calculation.

USE OF A CENTRIFUGAL ATOMIZATION PROCESS IN THE DEVELOPMENT OF RESEARCH REACTOR FUEL

  • Kim, Chang-Kyu;Park, Jong-Man;Ryu, Ho-Jin
    • Nuclear Engineering and Technology
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    • v.39 no.5
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    • pp.617-626
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    • 2007
  • A centrifugal atomization process for uranium fuel was developed in order to fabricate high uranium density dispersion fuel for advanced research reactors. Spherical powders of $U_3Si$ and U-Mo were successfully fabricated and dispersed in aluminum matrices. Thermal and mechanical properties of dispersion fuel meat were characterized. Irradiation tests at the research reactor HANARO confirm the excellent performance of high uranium density dispersion fuel.

Effect of Temperature and Humidity on the Performance Factors of a 15-W Proton Exchange Membrane Fuel Cell

  • Dien Minh Vu;Binh Hoa Pham;Duc Pham Xuan;Dung Nguyen Dinh;Vinh Nguyen Duy
    • Applied Chemistry for Engineering
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    • v.34 no.3
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    • pp.241-246
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    • 2023
  • Fuel cells are one of the renewable energy sources that have sparked a lot of scientific attention for solving problems related to the energy crisis and environmental pollution. One of the most crucial subjects concerning the utilization of fuel cells is modeling. Therefore, an analytical steady-state and dynamic fuel cell model was described in this study. The parameter for the identification process was investigated, and the MATLAB/Simulink implementation was demonstrated. A 15-W proton exchange membrane fuel cell was used to apply the suggested modeling methodology. Comparing experimental and simulation findings indicated that the model error was constrained to 3%. This study showed that temperature and humidity affect fuel cell performance.

DEVELOPMENT AND VALIDATION OF A NUCLEAR FUEL CYCLE ANALYSIS TOOL: A FUTURE CODE

  • Kim, S.K.;Ko, W.I.;Lee, Yoon Hee
    • Nuclear Engineering and Technology
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    • v.45 no.5
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    • pp.665-674
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    • 2013
  • This paper presents the development and validation methods of the FUTURE (FUel cycle analysis Tool for nUcleaR Energy) code, which was developed for a dynamic material flow evaluation and economic analysis of the nuclear fuel cycle. This code enables an evaluation of a nuclear material flow and its economy for diverse nuclear fuel cycles based on a predictable scenario. The most notable virtue of this FUTURE code, which was developed using C# and MICROSOFT SQL DBMS, is that a program user can design a nuclear fuel cycle process easily using a standard process on the canvas screen through a drag-and-drop method. From the user's point of view, this code is very easy to use thanks to its high flexibility. In addition, the new code also enables the maintenance of data integrity by constructing a database environment of the results of the nuclear fuel cycle analyses.

POST-IRRADIATION ANALYSES OF U-MO DISPERSION FUEL RODS OF KOMO TESTS AT HANARO

  • Ryu, H.J.;Park, J.M.;Jeong, Y.J.;Lee, K.H.;Lee, Y.S.;Kim, C.K.;Kim, Y.S.
    • Nuclear Engineering and Technology
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    • v.45 no.7
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    • pp.847-858
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    • 2013
  • Since 2001, a series of five irradiation test campaigns for atomized U-Mo dispersion fuel rods, KOMO-1, -2, -3, -4, and -5, has been conducted at HANARO (Korea) in order to develop high performance low enriched uranium dispersion fuel for research reactors. The KOMO irradiation tests provided valuable information on the irradiation behavior of U-Mo fuel that results from the distinct fuel design and irradiation conditions of the rod fuel for HANARO. Full size U-Mo dispersion fuel rods of 4-5 $g-U/cm^3$ were irradiated at a maximum linear power of approximately 105 kW/m up to 85% of the initial U-235 depletion burnup without breakaway swelling or fuel cladding failure. Electron probe microanalyses of the irradiated samples showed localized distribution of the silicon that was added in the matrix during fuel fabrication and confirmed its beneficial effect on interaction layer growth during irradiation. The modifications of U-Mo fuel particles by the addition of a ternary alloying element (Ti or Zr), additional protective coatings (silicide or nitride), and the use of larger fuel particles resulted in significantly reduced interaction layers between fuel particles and Al.

Power System Development of Unmanned Aerial Vehicle using Proton Exchange Membrane Fuel Cell (고분자 전해질 연료전지를 이용한 무인비행체 동력시스템 설계)

  • Jee, Yeong-Kwang;Sohn, Young-Jun;Park, Gu-Gon;Kim, Chang-Soo;Choi, Yu-Song;Cho, Sung-Baek
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.3
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    • pp.250-255
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    • 2012
  • In this paper, the development and performance analysis of a fuel cell-powered unmanned aerial vehicle is described. A fuel cell system featuring 1 kW proton exchange membrane fuel cell combined with a highly pressurized fuel supply system is proposed. For the higher fuel consumption efficiency and simplification of overall system, dead-end type operation is chosen and each individual system such as purge system, fuel supply system, cooling system is developed. Considering that fluctuation of exterior load makes it hard to stabilize fuel cell performance, the power management system is designed using a fuel cell and lithium-ion battery hybrid system. After integration of individual system, the performance of unmanned aerial vehicle is analyzed using data from flight and laboratory test. In the result, overall system was properly operated but for more duration of flight, research on weight lighting and improvement of fuel efficiency is needed to be progressed.

Study on Internal Reforming Characteristic of 1 kW Solid Oxide Fuel Cell Stack (1 kW 고체산화물 연료전지 스택의 내부개질 특성 연구)

  • CHOI, YOUNGJAE;AHN, JINSOO;LEE, INSUNG;BAE, HONGYOUL;MOON, JIWOONG;LEE, JONGGYU
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.4
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    • pp.377-383
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    • 2017
  • This paper presents the performance characteristics of a 1 kW solid oxide fuel cell (SOFC) stack under various internal reforming and fuel utilization conditions. The Research Institute of Industrial Science & Technology (RIST) developed the 9-cell stack using a $20{\times}20cm^2$ anode supported planar cell with an active area of $324cm^2$. In this work, current-voltage characteristic test, fuel utilization test, continuous operation, and internal reforming test were carried out sequentially for 765 hours at a furnace temperature of $700^{\circ}C$. The influence of fuel utilization and internal reforming on the stack performance was analyzed. When the 1 kW stack was tested at a current of 145.8 A with a corresponding fuel utilization of 50-70% (internal reforming of 50%) and air utilization of 27%, the stack power was approximately 1.062-1.079 kW. Under continuous operation conditions, performance degradation rate was 2.16%/kh for 664 hours. The internal reforming characteristics of the stack were measured at a current of 145.8. A with a corresponding fuel utilization of 60-75%(internal reforming of 50-80%) and air utilization of 27%. As fuel utilization and internal reforming ratio increased, the stack power was decreased. The stack power change due to the internal reforming ratio difference was decreased with increasing fuel utilization.