• 공업화학
• /
• 제3권4호
• /
• pp.535-546
• /
• 1992

The molten carbonate fuel cell(MCFC) has been under Intensive development for the last decade as a second generation fuel cell. The advantages of the MCFC over the phophoric acid fuel cell are higher efficiency, its ability to accept CO and $H_2$ as a fuel, lower material costs, and high operating temperature making internal reforming possible. These features, along with low atmospheric emissions, will open up a significant market as an attractive means of developing highly efficient power plant. This article reviews a status of the MCFC research and development, a principle of the MCFC, and cell and stack technology including the status of electrodes, matrices and electrolytes. Several technical difficulties which must be resolved to be commercialized art mainly focused.

• 한국수소및신에너지학회논문집
• /
• 제26권1호
• /
• pp.21-27
• /
• 2015

Hydrogen production from commercial diesel fuels is an attactive option for energy generation purpose due to the low cost and good availability of diesel fuels. However, in order to utilize commercial diesel fuels, the sulfur contents must be removed down to approximately 0.1 ppm level to protect the fuel cell catalysts from poisoning. Commercial catalysts $CoMo/Al_2O_3$ and $NiMo/Al_2O_3$ were tested for HDS (Hydrodesulfurization) of model diesel and commercial diesel. The experimental conditions were $250-400^{\circ}C$ and LHSV (Liquid Hourly Space Velocity) $0.27-2.12hr^{-1}$. $NiMo/Al_2O_3$ was found to be more effective than $CoMo/Al_2O_3$ in removing sulfur from model diesel. Based on the experimental results of model diesel, commercial diesel fuel purchased from a local petrol station was tested for HDS using $NiMo/Al_2O_3$. The GC-SCD (Gas Chromatography Sulfur Chemiluminescence Detector) results showed that the DMDBT (Dimethyldibenzothiophene) derivatives were fully removed from the commercial diesel fuel proving that HDS with $NiMo/Al_2O_3$ is technically feasible for industrial applications.

• Nuclear Engineering and Technology
• /
• 제41권2호
• /
• pp.171-178
• /
• 2009

The rate of delayed hydride cracking (DHC), V, has been measured in cold-worked and stress-relieved Zircaloy-4 fuel cladding using the Pin-Loading Tension technique. At $250^{\circ}C$ the mean value of V from 69 specimens was $3.3({\pm}0.8)x10^{-8}$ m/s while the temperature dependence up to $275^{\circ}C$ was described by Aexp(-Q/RT), where Q is 48.3 kJ/mol. No cracking or cracking at very low rates was observed at higher temperatures. The fracture surface consisted of flat fracture with no striations. The results are compared with previous results on fuel cladding and pressure tubes.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.277-279
• /
• 2005

The imbalance of energy demand and supply caused by rapid industrialization around the world and the associated environmental issues require and alternative energy source with possible renewable fuels. Political instability and depletion of cruel oils are other factors that cause fluctuation of oil price. Securing a new alternative energy source for the next century became an urgent issue that our nation is confronting with. As a matter of fact, the fuel cell technology can be widely used as next generation energy regardless of regions and climate. Specially, the ability of expansion and quick installation enable one to apply it for distributed power, where the technology is already gaining remarkable attentions for the application. Particularly, leading industrialized nations are focusing on the PEM fuel dell with anticipation that this technology will find their place of applications in the vehicles and homes. In this study, demonstrate the multi physics modeling of a proton exchange membrane(PEM) fuel cell with interdigitated flow field design. The model uses current balances, mass balance(Maxwell-Stefan diffusion for reactant, water and nitrogen gas) and momentum balance(gas flow) to simulate the PEM fuel cell behavior.

• 전기화학회지
• /
• 제12권2호
• /
• pp.173-180
• /
• 2009

DMFC (Direct Methanol Fuel Cell)용의 새로운 고분자 전해질 멤브레인을 개발하기 위하여 스티렌 단량체를 poly(tetrafluoroethylene perfluoropropyl vinyl ether) (PFA) 필름에 그라프트 중합 반응시킨 후에 술폰화 반응을 진행하였다. $\Upsilon$-ray를 이용하여 방사선 그라프트 중합 반응시킨 방사선 그라프트 필름의 술폰화 반응은 chlorosulfonic acid/dichloroethane (5 v/v%) 혼합 용액에서 진행하였다. PFA 그라프트 폴리스티렌 멤브레인 (PFA-g-PSSA)의 화학적, 물리적, 전기화학적 및 형태의 특성은 푸리에 변환 적외선 분광기 (FTIR), 이온전도도 측정기 및 주사전자현미경 (SEM)으로 분석하고 함수율과 메탄올 투과도도 측정하였다. PFA-g-PSSA 멤브레인으로 제작한 MEA의 단위전지 성능을 평가하였고, 전지의 셀 저항은 임피던스 분석 장치를 이용하여 측정하였다. PFA-g-PSSA 멤브레인으로 제조한 MEA는 Nafion 112로 제조한 MEA보다 우수한 DMFC 성능을 나타내었다.

• 한국세라믹학회지
• /
• 제56권2호
• /
• pp.130-145
• /
• 2019

Widespread commercialization of solid oxide fuel cells (SOFCs) is expected to be realized in various application fields with the advent of cost-effective fabrication of cells and stacks in high volumes. Cost-reduction efforts have focused on production yield, power density, operation temperature, and continuous manufacturing. In this article, we examine several issues associated with processing for SOFCs from the standpoint of the bimodal packing model, considering the external constraints imposed by rigid substrates. Optimum compositions of composite cathode materials with high volume fractions of the second phase (particles dispersed in matrix) have been analyzed using the bimodal packing model. Constrained sintering of thin electrolyte layers is also discussed in terms of bimodal packing, with emphasis on the clustering of dispersed particles during anisotropic shrinkage. Finally, the structural transition of dispersed particle clusters during constrained sintering has been correlated with the structural stability of thin-film electrolyte layers deposited on porous solid substrates.

• Nuclear Engineering and Technology
• /
• 제51권2호
• /
• pp.495-500
• /
• 2019

When a new fuel is developed, various mechanical properties are absolutely necessary for a safety analysis of the fuel for the licensing and prediction of its mechanical behavior during operation and accident conditions. In this paper, a mechanically equivalent surrogate plate of U-Mo dispersion fuel is presented using tungsten, substitute material of U-Mo particle. A surrogate plate, composed of tungsten/aluminum dispersion meat and aluminum alloy cladding, is manufactured with the same fabrication process with that of fuel plate except that a tungsten powder is used instead of U-Mo powder. A modal test showed that the surrogate plate and fuel plate have similar dynamic characteristics, and a tensile test demonstrated the similarity of the material property up to the yield strength range. The conducted tests proved that the surrogate tungsten plate has equivalent mechanical behaviors with that of a fuel plate, which leads to the acceptable use of a surrogate fuel assembly using tungsten/aluminum dispersion meat in various mechanical tests. The surrogate fuel assembly can be utilized for various out-of-pile characteristic tests, which are necessary for the licensing achievement of a research reactor that uses U-Mo dispersion fuel as a driver.

• Nuclear Engineering and Technology
• /
• 제47권3호
• /
• pp.306-314
• /
• 2015

This paper examines the difference in the value of the nuclear fuel cycle cost calculated by the deterministic and probabilistic methods on the basis of an equilibrium model. Calculating using the deterministic method, the direct disposal cost and Pyro-SFR (sodium-cooled fast reactor) nuclear fuel cycle cost, including the reactor cost, were found to be 66.41 mills/kWh and 77.82 mills/kWh, respectively (1 mill = one thousand of a dollar, i.e., $10^{-3}$ $). This is because the cost of SFR is considerably expensive. Calculating again using the probabilistic method, however, the direct disposal cost and Pyro-SFR nuclear fuel cycle cost, excluding the reactor cost, were found be 7.47 mills/kWh and 6.40 mills/kWh, respectively, on the basis of the most likely value. This is because the nuclear fuel cycle cost is significantly affected by the standard deviation and the mean of the unit cost that includes uncertainty. Thus, it is judged that not only the deterministic method, but also the probabilistic method, would also be necessary to evaluate the nuclear fuel cycle cost. By analyzing the sensitivity of the unit cost in each phase of the nuclear fuel cycle, it was found that the uranium unit price is the most influential factor in determining nuclear fuel cycle costs.

• Nuclear Engineering and Technology
• /
• 제50권8호
• /
• pp.1339-1348
• /
• 2018

The aim of this paper is to determine neutronic performances of the light water reactor (LWR) spent fuel mixed with fertile thorium fuel in a FFHR. Time dependent three dimensional calculations for major technical data, such as blanket energy multiplication, tritium breeding ratio, cumulative fissile fuel enrichment and burnup have been performed by using Monte Carlo Neutron-Particle Transport code MCNP5 1.4, coupled with a novel interface code MCNPAS, which is developed by our research group. A self-sustaining tritium breeding ratio (TBR>1.05) has been kept throughout the calculations. The study has shown that the fissile fuel quality will be improved in the course of the transmutation of the LWR spent in the FFHR. The latter has gained the reusable fuel enrichment level conventional LWRs between one and two years. Furthermore, LWR spent fuel - thorium mixture provides higher burn-up values than in light water reactors.

• Nuclear Engineering and Technology
• /
• 제54권4호
• /
• pp.1355-1362
• /
• 2022

Nuclear fuel, including its fresh state, must be handled safely due to its critical and hazardous nature. Under normal transport conditions, several interactions take place among different components, such as transport cask used for loading the nuclear fuel and tie-down structure to attach with the vehicle. To ensure structural integrity of the nuclear fuel, vibrations and impacts transmitted from the vehicle must be sufficiently reduced. Therefore, in this study, we conducted two transportation tests from Daejeon to Kijang in Korea to verify the vehicle-induced vibrational characteristics of the KJRR-F fresh nuclear fuel when transported under normal transport conditions. The speed and location of the vehicle were obtained via GPS, and the accelerations between the vehicle and the KJRR-F fresh nuclear fuel were measured. Additionally, using the acceleration results, a structural analysis was conducted to confirm the structural integrity of the nuclear fuel under the most severe conditions during normal transport.