• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.39-44
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• 2015

The VHTR (Very High Temperature gas-cooled nuclear Reactor) has been considered as a major heat source and the most safe generation IV type reactor for mass hydrogen production to prepare for the hydrogen economy era. The VHTR satisfies goals for the GIF (Generation IV International Forum) policy such as sustainablility, economics, reliability and proliferation resistance and physical protection, and safety. As a part of a VHTR economic analysis, we have studied the VHTR construction cost and operation and maintenance cost. However, it is somewhat difficult to expect the ripple effect on the whole industry due to the lack of information about Inter-industries relationship. In many case, the ripple effect are based on experts' knowledge or uncertain qualitative assumptions. As a result, we propose quantitative analysis techniques for ripple effects such as the production inducement effect, added value inducement effect, and employment inducement effect for VHTR 600MWt${\times}$4 modules construction and operation ripple effect based on NOAK (Nth Of A Kind). Because inducement effect values have been published annually, we predict inducement effect's relation function and estimated values including production inducement effect value, added value inducement effect value, and employment inducement effect value using time series and estimated values are verified with published inducement effects' value. This paper presents a new method for the ripple effect and preliminary ripple effect consequence using a time series analysis and inter-industry table. This ripple effect analysis techniques can be applied to effect expectation analysis as well as other type reactor's ripple effect analysis including VHTR for process heat.

• Carbon letters
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• v.7 no.3
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• pp.196-200
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• 2006

Graphite has hexagonal closed packing structure with two bonding characteristics of van der Waals bonding between the carbon layers at c axis, and covalent bonding in the carbon layer at a and b axis. Graphite has high tolerant to the extreme conditions of high temperature and neutron irradiations rather than any other materials of metals and ceramics. However, carbon elements easily react with oxygen at as low as 400C. Considering the increasing production of today of hydrogen and electricity with a nuclear reactor, study of oxidation characteristics of graphite is very important, and essential for the life evaluation and design of the nuclear reactor. Since the oxidation behaviors of graphite are dependent on the shapes of testing specimen, critical care is required for evaluation of nuclear reactor graphite materials. In this work, oxidation rate and amounts of the isotropic graphite (IG-110, Toyo Carbon), currently being used for the Koran nuclear reactor, are investigated at various temperature. Oxidation process or principle of graphite was figured out by measuring the oxidation rate, and relation between oxidation rate and sample shape are understood. In the oxidation process, shape effect of volume, surface area, and surface to volume ratio are investigated at $600^{\circ}C$, based on the sample of ASTM C 1179-91.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.175-188
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• 2023

Global interest in hydrogen energy is increasing as an eco-friendly future energy that can replace fossil fuels. Accordingly, a next-generation hydrogen production technology using microorganisms, nuclear power, etc. is being developed, while a lot of time and effort are still required to overcome the cost of hydrogen production based on fossil fuels. As a way to minimize greenhouse gas emissions in the hydrocarbon-based hydrogen production process, methane direct decomposition technology has recently attracted attention. In order to improve the economic feasibility of the process, the simultaneous production of value-added carbon materials with hydrogen can be one of the most essential aspects. For that purpose, various studies on catalysis related to the quality and yield of high-value carbon materials such as carbon nanotubes (CNTs). In terms of process technology, a number of the research and development of fluidized-bed reactors capable of continuous production and improved gas-solid contact efficiency has been attempted. Recently, methane direct decomposition technology using a fluidized bed has been developed to the extent that it can produce 270 kg/day of hydrogen and 1000 kg/day of carbon. Plus, with the development of catalyst regeneration, separation and recirculation technologies, the process efficiency can be further improved. This review paper investigates the recent development of catalysts and fluidized bed reactor for methane direct pyrolysis to identify the key challenges and opportunities.

• Corrosion Science and Technology
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• v.6 no.2
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• pp.37-43
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• 2007

Iodine sulfur (IS) process is one of the promising processes for a hydrogen production by using a high temperature heat generated by a very high temperature gas cooled reactor(VHTR) in the nuclear power industries. Even though the IS process is very efficient for a hydrogen production and it is not accompanied by a carbon dioxide evolution, the highly corrosive environment of the process limits its application in the industry. Corrosion tests of selected materials were performed in sulfuric acid to select appropriate materials compatible with the IS process. The materials used in this work were Fe-Cr alloys, Fe-Ni-Cr alloys, Fe-Si alloys, Ni base alloys, Ta, Ti, Zr, SiC, Fe-Si, etc. The test environments were 50 wt% sulfuric acid at $120^{\circ}C$ and 98 wt% at $320^{\circ}C$. Corrosion rates were measured by using a weight change after an immersion. The surface morphologies and cross sectional areas of the corroded materials were examined by using SEM equipped with EDS. Corrosion behaviors of the materials were discussed in terms of the chemical composition of the materials, a weight loss, the corrosion morphology, the precipitates in the microstructure and the surface layer composition.

• Journal of Korea Technology Innovation Society
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• v.6 no.4
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• pp.462-479
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• 2003

The policy trends of use and the development of nuclear power in the United States, France, United Kingdom. Germany, Russia, China, Japan and Korea are briefly investigated. Nuclear power technology has been developed as the national policy in the nuclear-advanced countries. 50 years has passed since the declaration of "Atoms for Peace" by USA President Eisenhour in December 1953. Recently, it appears to revitalize the nuclear power program in world major countries in order to recover the shortage of electric power and to curb the excess emission of carbon dioxide as well as to secure competitiveness in electricity markets. Advanced countries are making new initiatives for the development of the fourth generation nuclear power system. Furthermore, wide-ranged use and development of nuclear power technologies are expected in district heating in commercial sectors, power in the space exploration, and propulsion power of large tankers and spaceships. High temperature gas cooled nuclear power reactor will be applied for mass production of hydrogen energy in the future.

• Nuclear Engineering and Technology
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• v.17 no.1
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• pp.8-15
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• 1985

A model for thermal interactions of debris/water with gas flow from within and below debris bed was presented for severe accident analysis in LWR. The consumption of steam, production of hydrogen in the debris bed, generation of gases from below debris bed and generation of chemical heat are included in the conservation equations. The model has been incorporated in the MARCH code to estimate the gas production due to both metal/oxidation and hot debris/concrete interaction. The results indicate that the hydrogen source can potentially give a significant impact on the containment pressure transient and the conductive heat loss to concrete and the convective gas cooling in the debris bed have a small effect on the debris bed coolability. However, the reheating and melting of the debris particles could be delayed by the interaction of debris with concrete.

• Nuclear Engineering and Technology
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• v.39 no.1
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• pp.31-42
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• 2007

Energy supply is increasingly showing up as a major issue for electricity supply, transportation, settlement, and process heat industrial supply including hydrogen production. Nuclear power is part of the solution. For electricity supply, as exemplified in Finland and France, the EPR brings an immediate answer; HTR could bring another solution in some specific cases. For other supply, mostly heat, the HTR brings a solution inaccessible to conventional nuclear power plants for very high or even high temperature. As fossil fuels costs increase and efforts to avoid generation of Greenhouse gases are implemented, a market for nuclear generated process heat will be developed. Following active developments in the 80's, HTR have been put on the back burner up to 5 years ago. Light water reactors are widely dominating the nuclear production field today. However, interest in the HTR technology was renewed in the past few years. Several commercial projects are actively promoted, most of them aiming at electricity production. ANTARES is today AREVA's response to the cogeneration market. It distinguishes itself from other concepts with its indirect cycle design powering a combined cycle power plant. Several reasons support this design choice, one of the most important of which is the design flexibility to adapt readily to combined heat and power applications. From the start, AREVA made the choice of such flexibility with the belief that the HTR market is not so much in competition with LWR in the sole electricity market but in the specific added value market of cogeneration and process heat. In view of the volatility of the costs of fossil fuels, AREVA's choice brings to the large industrial heat applications the fuel cost predictability of nuclear fuel with the efficiency of a high temperature heat source tree of Greenhouse gases emissions. The ANTARES module produces 600 MWth which can be split into the required process heat, the remaining power drives an adapted prorated electric plant. Depending on the process heat temperature and power needs, up to 80% of the nuclear heat is converted into useful power. An important feature of the design is the standardization of the heat source, as independent as possible of the process heat application. This should expedite licensing. The essential conditions for success include: ${\bullet}$ Timely adapted licensing process and regulations, codes and standards for such application and design ${\bullet}$ An industry oriented R&D program to meet the technological challenges making the best use of the international collaboration. Gen IV could be the vector ${\bullet}$ Identification of an end user(or a consortium of) willing to fund a FOAK

• Journal of the Korean Vacuum Society
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• v.2 no.4
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• pp.416-423
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• 1993

Hydrogen depth profiling was performed by H(19F, $\alpha$${\gamma}$) nuclear resonance reactin . A cesium sputtering ion sorce and 1.7MV Tandem Van de Graaff accelerator was used for the production of 6.5MeV 19F ion. The ${\gamma}$ rays produced by the reaction were measure dby 3" $\times$3" and 6" $\times$8" Nal detectors . A test measurement was done for hydrogen contaminatin layer of a bare silicon wafer, Si3N4(H) and Zr(O)a-Si/Si for the purpose of verifying the applicability , detection limit and the reliability of the method.ility of the method.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.1
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• pp.62-68
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• 2006

High temperature electrolysis is a promising technology to produce massively hydrogen using renewable and nuclear energy. Solid oxide fuel cell materials are candidates as the components of steam electrolysers. However, the polarization characteristics of the typical electrode materials during the electrolysis have not been intensively investigated. In this study, NiO electrode was deposited on YSZ electrolyte by spin coat process and firing at $1300^{\circ}C$. Pt electrode was applied on the other side of the electrolyte to compare the polarization characteristics with those by NiO during electrolysis. The $H_2$ evolution rate was also monitored by measuring the electromotive force of Lambda probe and calculated by thermodynamic consideration. At low current density, Pt showed lower cathodic polarization and thus higher current efficiency than Ni, but the oxidation of Ni into NiO caused the increase of anodic resistance with increasing current density. High overpotential induced high power consumption to produce hydrogen by electrolysis.

• Journal of the Korean institute of surface engineering
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• v.52 no.6
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• pp.321-325
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• 2019

Triso-type coating layers of silicon carbide and graphite on UO₂ paticulate nuclear fuel were prepared by using fluidized bed type chemical vapor deposition and self-propagating high temperature synthesis methods to make a coated nuclear fuel of a power plant for hydrogen mass-production. The source and carrier gases were the mixture of methyltrichlorosilane and propane, and inert argon. Chemical analysis and microstructure observation showed that the coated layers were inner graphite, middle silicon carbide and outer graphite. The elastic modulus and nano-hardness of the silicon carbide layer were 503 [GPa] and 36 [GPa], respectively.