Takayuki Terai

Takayuki Terai
The University of Tokyo | Todai · Faculty & Graduate School of Engineering

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432
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Publications

Publications (432)
Article
Full-text available
Proton exchange membrane fuel cells (PEMFCs) have attracted considerable attention as distributed power sources for automotive and residential applications. In PEMFCs, platinum (Pt) nanoparticles supported on carbon materials are used as electrocatalysts for oxygen reduction reactions. However, improved durability of the electrocatalysts is urgentl...
Article
Glassy carbon substrates were implanted with 100 keV platinum ions. The implanted samples were analyzed using cross-sectional transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy. Ion beam sputtering significantly affected the depth profile during platinum-ion implantation. Cross-sectional TEM revealed that the implanted plat...
Article
The ion beam-induced defects in carbon supports for platinum (Pt) nanoparticles have been found to enhance the catalytic activity. Highly oriented pyrolytic graphite (HOPG) was irradiated with 380 keV argon ions (Ar+), and Pt nanoparticles were then deposited on it by a radio frequency (rf) magnetron sputtering method. The Pt nanoparticle size on A...
Article
In a fusion reactor, strict control of tritium is required from the viewpoints of sufficient fuel balance and radiological hazard. Fabrication of tritium-impermeable ceramic coatings is a promising solution, and ceramic coatings have been investigated for several decades. In recent years, several irradiation tests have been conducted for the cerami...
Article
Full-text available
The discovery of hydrogen-induced electron localization and highly insulating states in d-band electron correlated perovskites has opened a new paradigm for exploring novel electronic phases of condensed matters and applications in emerging field-controlled electronic devices (e.g., Mottronics). Although a significant understanding of doping-tuned...
Article
Erbium oxide (Er2O3) is a candidate material for tritium permeation barriers (TPB) applied to fusion blanket systems. To permeate through a TPB coating on a metal substrate, a hydrogen isotope must first adsorb on the surface, and then penetrate from the surface into the interior. In this work, Er2O3 coatings were fabricated by arc source assisted...
Article
Point defects created by neutron/electron irradiation often determine the performance and the chemical stability and activity of oxide materials. Oxygen vacancies constitute a common point defect in metal oxides, such as erbium oxide (Er 2 O 3), one of the candidate materials for tritium permeation barriers in fusion blanket systems. However, a sys...
Article
Ion irradiation is well-known as a versatile tool for manipulating the physical, chemical and magnetic properties of carbon materials. Recently, the ion-beam-induced defects in carbon supports for platinum (Pt) nanoparticles have been found to enhance catalytic activity during the oxygen reduction reaction. This finding suggests that the electronic...
Article
Ceramic coatings have been investigated as tritium permeation barrier for several decades; however, there is little knowledge about irradiation effects on the coatings. In this study, yttrium oxide coatings were fabricated on reduced activation ferritic/martensitic steel substrates by radio frequency reactive magnetron sputtering, and their microst...
Article
γ-ray irradiation effect on deuterium permeation through three kinds of ceramic coatings with different crystal structures has been investigated. Deuterium permeation flux through the coatings increased during γ-ray irradiation at 250–300 °C, but changes in the permeation flux were not detected at above 300 °C. The permeation flux through an erbium...
Article
Full-text available
Deuterium permeation through a fusion-relevant ferritic steel F82H with and without erbium oxide coatings under γ-ray irradiation has been investigated in a temperature range from 300 to 700 °C. The deuterium permeation flux through F82H sample increased by γ-ray irradiation at lower temperatures below 450 °C. The irradiation effect increased with...
Article
TiO2 thin films have received attention as intermetallic diffusion barriers in hydrogen-permeable membranes used for the extraction of purified H2 from chemical reactors. We report the fabrication of thin (~100 nm) TiO2 films on Si(111) substrates by pulsed laser deposition. Anatase and rutile phases are found to coexist in the as-deposited TiO2 fi...
Article
Tritium handling in fusion reactors is important for economical fuel cycles and radiological safety; however, the extremely limited number of studies on tritium permeation through structural materials under irradiation conditions has been reported. In this study, γ-ray irradiation effect on tritium permeation has been investigated using three kinds...
Article
Erbium oxide has been investigated as a tritium permeation barrier material in a D-T fusion reactor fuel system for more than a decade. Erbium oxide normally forms the cubic phase; however, the uncommon monoclinic phase was formed under ion irradiation or high pressure conditions. In this study, the monoclinic erbium oxide coatings were prepared to...
Preprint
Full-text available
High activity is one of the primary requirements for the catalysts in proton exchange membrane fuel cell applications. Platinum (Pt) is the best-known catalyst especially for oxygen reduction at the cathode; however, further activity improvements are still required. Previous computational studies suggested that the catalytic activity of Pt nanopart...
Article
Direct n-octane combustion is demonstrated with a solid oxide fuel cell (SOFC) with a porous nickel and yttria-stabilized zirconia (Ni-YSZ) cermet anode. We systematically investigate the influences of the steam/carbon ratio (S/C) and the cell temperature on the internal steam reforming reaction and the electrochemical reaction on the anode by eval...
Article
In order to evaluate the potential of erbium oxide films in applications as hydrogen (H) permeation barriers, we fabricated high-quality Er2O3 thin films by ion beam sputter deposition on Si(100) as an epitaxial substrate. The physical structures of the thin films were characterized by scanning X-ray diffraction and the process of hydrogen permeati...
Article
In order to realize the photoluminescence of semiconducting β-FeSi2 homoepitaxial films, surface preparation of single crystalline β-FeSi2 is of critical importance. An atomically flat and clean substrate surface of β-FeSi2 was prepared by sputtering with 2 keV Ar+ ions or by heating at 850 °C. The structure of the native surface oxide and the remo...
Article
Glassy carbon (GC) substrates were irradiated with 380 keV Ar ions (Ar+) at fluences between 1.0 × 1013 and 1.0 × 1016 ions/cm2, and then heated at 400 °C in an N2 atmosphere for 1 h. Platinum nanoparticles were then deposited by a radio-frequency magnetron sputtering method on this GC surface. We investigated the influence of the GC substrate irra...
Article
This paper describes a new experimental system designed to investigate tritium mass transfer properties in materials important to fusion technology. Experimental activities were carried out at the Safety and Tritium Applied Research (STAR) facility located at the Idaho National Laboratory (INL). The tritium permeation measurement system was develop...
Article
The International Fusion Materials Irradiation Facility (IFMIF), presently in the Engineering Validation and Engineering Design Activities (EVEDA) phase was started from 2007 under the frame of the Broader Approach (BA) agreement. In the activities, a prototype Li loop with the world's highest flow rate of 3,000 L/min was constructed in 2010, and i...
Article
Full-text available
We investigated the ion-track grafting of vinylbenzyl chloride (VBC) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film using different grafting media for applications as anion exchange membranes for fuel cells. In an attempt to increase the grafting yield, we applied a poor solvent system as the grafting medium, i.e., a mixture of water and...
Article
Single-phase nanocrystalline thin films of Er2O3 (440) has been first prepared using Si (100) substrates by ion beam sputter deposition at 700°C at a pressure of <10-7Torr and in-situ annealing at 750°C at a pressure of <10-9Torr. Er silicides formed during the deposition are eliminated via the annealing, which results in the single phase and the s...
Article
Solid oxide fuel cell (SOFC) consisting of ion conductive ceramics has various advantages such as the high generating efficiency, the utilization of hydrocarbon-containing fuel and the non-necessity of expensive rare metal catalyst. Yttria-stabilized Zirconia (YSZ) or Gadolinium-doped Ceria (GDC) are mainly used as the electrolyte for SOFC. Stronti...
Article
Solid oxide fuel cell (SOFC) can, in principle, use not only hydrogen but also hydrocarbon fuels which have high energy density. Then, SOFC is a promising power source for many potential mobile robot applications. Octane is a good candidate as fuel due to high boiling point enough to be in the liquid phase even at high temperatures in summer. Perfo...
Article
Solid oxide fuel cell (SOFC) consisting of ion conductive ceramics has various advantages such as the high generating efficiency, the utilization of hydrocarbon-containing fuel and the non-necessity of expensive rare metal catalyst. Sr and Mg dopoed Lanthunum Gallate (La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ , LSGM) is a well-known electrolyte for solid o...
Article
A small and high-performance solid oxide fuel cell (SOFC) system is promising as a power source for many potential mobile robot applications. To realize the small SOFC system, the direct use of liquid hydrocarbon fuel, which has high energy density and is easy to storage and carry, is desirable. The optimization of type of fuel, operating condition...
Article
Source term for severe accident analysis of molten salt reactors(MSRs) has been investigated as part of preliminary efforts to develop MSRs. As a severe accident of MSRs, exposure of heated fluoride fuel molten salt to atmosphere was assumed to take place. Vaporization of fluoride molten salt was studied by means of the two methods, the Knudsen eff...
Article
Silicon carbide (SiC) coating is one of the countermeasures for the prevention of oxidation and hydrogen embrittlement of fuel claddings because SiC has high resistance of oxidation and hydrogen permeation. Hydrogen permeation and oxidation experiments for the cladding materials with SiC coatings were conducted in unirradiated conditions. The sputt...
Article
When a type-A zeolite is immersed in molten LiCl-KCl eutectic salt, the alkali and halogen elements in the salt phase are absorbed in the vacancies of the zeolite in the form of ions. Recently, it was revealed that I- in molten LiCl-KCl-KI salt exhibited greater absorption in the zeolite than Cl-, although Br- in molten LiCl-KCl-KBr salt did not sh...
Article
In this study, we report results using first-principles density functional theory calculations for four critical aspects of the interaction: H adsorption on Er2O3 surface, surface-to-subsurface penetration of H into Er2O3, bulk diffusion of H in Er2O3, and trapping of H at vacancies. We identify surface stable adsorption positions and find that H p...
Article
The bulk thermal conductivity is analyzed by the Finite Element Method (FEM) for the two phase material which consists of one dispersed phase and the other continuous phase. The effects of the spatial distributions and the shapes of the dispersed phase on the bulk thermal conductivity are quantitatively evaluated. The analyzed results reveal the pa...
Article
Diffusion of interstitial atomic hydrogen in erbium oxide (Er2O3) was investigated using density functional theory (DFT) and molecular dynamics (MD) methods. Hydrogen diffusivity in bulk, on (0 0 1) surface, and along Σ13 (4-3-1)/[1 1 1] symmetric tilt grain boundaries (GBs) were evaluated in a temperature range of 673-1073 K, as well as hydrogen d...
Article
Low concentration tritium permeation experiments have been performed on uncoated F82H and Er2O3-coated tubular samples in the framework of the Japan-US TITAN collaborative program. Tritium permeability of the uncoated sample with 1.2 ppm tritium showed one order of magnitude lower than that with 100% deuterium. The permeability of the sample with 4...
Article
Hydrogen isotope concentrations in erbium oxide coatings fabricated by filtered arc deposition and metal–organic decomposition have been investigated using nuclear reaction analysis and secondary ion mass spectroscopy. It was found that the deuterium concentration in the coatings fabricated by filtered arc deposition was 300–500 atomic parts per mi...
Article
Understanding surface properties of Er2O3, especially in relation to adsorption and permeation of atomic hydrogen, is of considerable importance to the study of tritium permeation barriers. In this work, hydrogen diffusion pathways through the low-index (1 0 0), (1 1 0), and (1 1 1) surfaces of cubic Er2O3 have been calculated using density functio...
Article
High-level radioactive wastes generated after reprocessing spent nuclear ftiels from nuclear reactors include long-lived radioactive nuclides. Recently, the transmutation method using actinide hydride targets has been proposed to reduce the amount of actinide in nuclear wastes. One of the major R&D items to establish the transmutation method is dev...
Article
Various kinds of chemical traps are used for the removal of gaseous radionuclides, fluorine, etc in the process-off gas of uranium conversion facility or similar facilities. The spent fillers such as sodium fluoride (NaF), magnesium fluoride (CaF2), or activated alumina (A12O3) from the chemical traps should be reused as useful materials, or conver...
Article
Introduction For many potential mobile robot applications, current power supply technology (such as the lithium ion battery technology) is in fact a key limiting factor due to its low energy density. Solid oxide fuel cells (SOFCs) are a promising alternative and can overcome limitations of current battery technology. This is because SOFCs can use n...
Article
Sr and Mg dopoed Lanthunum Gallate (La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ , LSGM) is a well-known electrolyte for solid oxide fuel cell because of the high conductivity. Thin film material can exhibit different characterization from bulk material. Thus, electrochemical characterization of the LSGM thin film electrolyte was measured by impedance spectro...
Article
Research and development of a water-splitting hydrogen-production method, called the iodine–sulfur (IS) process, has been conducted as one of the heat applications of high temperature gas-cooled reactor. Among the unit operations in this IS process, we have investigated electro-electrodialysis (EED) using an ion-exchange membrane to increase a hydr...
Article
Electro-electrodialysis (EED) has been applied to thermochemical water-splitting hydrogen production iodine–sulfur process in order to enhance HI in a HI–I2–H2O mixture (HIx solution). In this paper, in order to understand the behavior of the components (I2, H+, I−, and H2O) of the HIx solution in the membranes on absorption equilibrium, each compo...
Article
The behaviors of anion fission product (FP) elements to be absorbed into zeolite in molten LiCl–KCl eutectic salt were studied using iodine, bromine, and tellurium. First, the type-A zeolite was selected as the most suitable type of zeolite among type-A, type-X, and type-Y zeolites through experiments in which zeolites were heated together with LiC...
Article
Nanoparticles were formed by 100-keV tungsten-ion implantation in unpolished glassy carbon substrates at different fluences. The implanted samples were analyzed by Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, hydrodynamic voltammetry using a rotating disk electrode, and field emission scanning electron microscopy. A sig...
Article
Glassy carbon (GC) substrates were implanted with 100 keV tungsten ions at retained fluences of 4 × 1016 and 6 × 1016 ions/cm2 and surface-etched electrochemically in order to prepare tungsten-carbide (WC) nanoparticles on their topmost layers. The calculated current efficiency for the electrochemical etching was nearly the same for the two samples...
Article
First-principles plane wave calculations based on spin-polarized density functional theory (DFT) and generalized gradient approximation (GGA) have been used to study the adsorption of H atoms on cubic Er2O3 (0 0 1) surface. We identify stable adsorption positions and find that H preferentially adsorbs on top of fourfold-hollow sites and transfers e...
Article
A tritium permeation barrier is a promising solution for the problems of tritium loss and radiological safety in fusion blanket systems. In recent years, erbium oxide coatings have shown remarkable permeation reduction factors. One of the remaining issues for the coatings is the establishment of plant-scale fabrication. In this study, erbium oxide...
Article
Deuterium permeation through Er2O3-metal coatings showed that the metal layers had small effects on the permeation behavior. The Er2O3-Fe coating increased permeation reduction factor to over 103 by crystallization of the inner Er2O3 layer and oxidation of the outer Fe layer. In the Er2O3-Er coating, the Er layer oxidized completely and merged with...
Article
Li-Pb compatibility of Er2O3 and Er2O3-Fe two-layer coatings has been explored for an understanding of corrosion behaviors and effects of the protection layer. The coatings wee peeled off after static Li-Pb immersion test at 600 degrees C due to the degradation of adhesion between the coating-substrate interface. A loss of Er and then subsequent co...
Article
To understand the microscopic mechanism of H diffusion in tritium permeation barrier (TPB), we have explored the energetics and mobility of neutral hydrogen in α-Al2O3 with hexagonal structure as well as sequioxide Er2O3 with cubic bixbyite structure using first-principles density-functional calculations. The comparison of the most energetically fa...
Article
Enthalpy of Li2TiO3, which was synthesized by a neutralizing method and its Li/Ti ratio was determined to be Li/Ti ratio (mol/mol) = 1.97, was measured by a drop calorimeter, and its heat capacity was derived as a function of temperature. XRD (X-ray diffraction) analysis of the sample before and after the enthalpy measurement indicated no phase cha...
Conference Paper
Thermal fatigue may occur downstream from mixing tee junctions where hot and cold water are turbulently mixed. Depending on the momentum of the incoming flows, different characteristic eddies are formed which create a local hot spot on the inner surface of the pipe. The hot spot have an unstable discrete boundary that spatially oscillates and this...
Article
Polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) are typical fluoropolymers displaying several desirable technological properties such as electrical insulation and high chemical resistance. When their surfaces are irradiated with ion beams, dense micro-protrusions formed after the emergence and spread of micropores across the...
Conference Paper
Spray pyrolysis deposition (SPD) is a potential method for mass production of ceramics thin film with low fabrication cost. We investigated on the SPD method, and demonstrated that it is a noble method to prepare the electrolyte thin film for solid oxide fuel cells. Controlling the substrate temperature low to about 150 °C during the SPD process is...
Article
In order to clarify the tritium behavior in Pb-Li blanket system, the solubility of hydrogen isotopes in the Pb-Li eutectic alloy was experimentally investigated. The effects of (i) Li preferential evaporation from Pb-Li, (ii) thermal convection in a quartz-glass reaction tube and (iii) difference in crucible materials between Al2O3 and W on the so...
Article
The temperature measurements of mixed oxide (MOX) and UO2 fuels during irradiation suggested that the thermal conductivity degradation rate of the MOX fuel with burnup should be slower than that of the UO2 fuel. In order to explain the difference of the degradation rates, the quasi-two phase material model is proposed to assess the thermal conducti...
Article
In the thermochemical water-splitting iodine–sulfur process for hydrogen production, an electromembrane process (electro-electrodialysis) was applied to increase the HI molality of a HI–I2–H2O mixture. In order to investigate the temperature dependence of the membrane performance for increasing the HI concentration, a theoretical formula for the pe...
Article
Crystal grain growth and crystallization of lithium metatitanate with excess Li (Li2+xTiO3+y), which is expected as an advanced ceramic breeder for a future DEMO fusion reactor, were studied in this paper. By the observation of sintered pellets using scanning electron microscope, it was shown that the Li2.1TiO3+y specimens, which have small grains...
Article
Titanium plates coated by iron were fabricated electrochemically as a candidate hydrogen isotope permeation window for liquid lithium. Contacting the window to liquid lithium containing deuterium between 673 and 873 K, its permeation behavior and resistance to degradation were investigated. The iron-coated window showed less permeability than the b...
Article
A PbLi thermal convection loop with the flow rate of a few centimeters per second was designed and constructed to perform an in-situ tritium release experiment in a neutron source of the YAYOI reactor of The University of Tokyo. Tritium was generated by the nuclear reaction of Li with neutrons released through a 1-mm-thick steel tube and followed t...
Article
The engineering validation and engineering design activity (EVEDA) for the International Fusion Materials Irradiation Facility (IFMIF) is proceeding as one of the ITER broader approach activities. In the concept of the IFMIF, two 40 MeV deuteron beams are injected into a liquid Li stream (Li target) flowing at a velocity of 15 m s−1. The EVEDA Li t...
Article
Tissue reconstruction is the aim of regeneration medicine and tissue engineering. One of the techniques is cell sheet engineering, which requires creating a contiguous cell sheet and harvesting it safely. To create a favorable substrate for cultivation, we attempted to fabricate the microstructure at polytetrafluoroethylene (PTFE) surfaces using io...
Article
Corrosion experiments for RAFM, JLF-1 steel (Fe–9Cr–2W–0.1C) in three types of liquid breeders (i.e. Li, Pb–17Li and Flinak) were performed at 600 °C. The influence of the different experimental parameters, such as a flowing condition, an exposure time and a geometric condition, on the corrosion behavior was investigated. The present study focused...
Article
In IFMIF/EVEDA, tasks for lithium target system consist of 5 validation tasks (LF1-5) and a design task (LF6), and are shared by Japan and Europe. Japan is covering LF1, LF2, LF4, LF5 and LF6, and JAEA as an Implementing Agency is organizing these tasks. Japanese universities contribute these tasks. The purpose of LF1 task is to construct and opera...
Article
The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 (6Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% 6Li. In this paper, a new lithium isotope separation technique using an ionic-liquid impregnated organic membrane is proposed. In order to separate and concen...
Article
Lithium titanate (Li2TiO3) is one of the most promising candidates among tritium breeding materials because of its good tritium release characteristics. However, the mass of Li2TiO3 decreased with time in a hydrogen atmosphere by the reduction of Ti and Li evaporation. In order to prevent the mass decrease at high temperatures, advanced tritium bre...
Article
The crystal structure at high temperature and the thermal expansion properties of Li2TiO3, important for use as a tritium breeding material in fusion reactors, have been investigated with high resolution by using high temperature synchrotron X-ray diffraction. The temperature dependence of lattice constants and molar volumes were calculated from th...
Article
Deuterium permeation measurements and microstructure analyses on erbium oxide coating deposited by filtered arc deposition have been investigated. It is found that the permeation suppression efficiency is proportional to the coating thickness in case of the coating without pores and cracks reaching to the substrate. A phase transformation of the co...
Article
In this study, deuterium permeation measurements for SS316 and F82H steels coated with amorphous silicon carbide films by radio frequency magnetron sputtering are performed. The driving deuterium pressure dependence of the coated sample shows a large surface contribution. Deuterium trapping in the amorphous structure is suggested by the temporal ch...
Article
The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 (6Li) in tritium breeding materials. New lithium isotope separation technique using ionic-liquid impregnated organic membranes (Ionic-Liquid-i-OMs) have been developed. Lithium ions are able to move by electrodialysis through certain Ionic-Liqu...
Article
Yttrium is a candidate for hydrogen hot trapping in a liquid tritium breeder of a fusion reactor blanket and in the flowing target of the International Fusion Materials Irradiation Facility, IFMIF. Nitrogen impurity in lithium is expected to decrease hydrogen trapping but this has not been confirmed. This study, directed at developing a hydrogen pe...
Article
The Engineering Validation and Engineering Design Activities (EVEDA) of the International Fusion Materials Irradiation Facility (IFMIF) have been started. As Japanese activities for the target system, the EVEDA Lithium (Li) Test Loop to simulate hydraulic and impurity conditions of the IFMIF Li loop is under design. The feasibility of the thermo-me...
Article
Corrosion of Er2O3 coatings in liquid Li is crucial issue for Li blanket system development. Recent researches revealed that the Er2O3 forms LiErO2 in Li and the reaction rate depends on the O concentration in Li. In this paper, the detailed chemical behavior of Er2O3 and LiErO2 in Li is investigated to develop a methods to prevent the corrosion of...
Article
To mitigate magnetohydrodynamic (MHD) pressure drop in liquid Li blanket system, Er2O3 coating is under development. Er can oxide in Li and form Er2O3 layer which may have electrical insulating capacity. To investigate formation of Er2O3 layer on Er, immersion tests of Er plate into high temperature Li at 773K and 973K are carried out. Li2O was int...
Article
Nitrogen trapping is a key technology for liquid lithium usage, but has not been well investigated in dynamic conditions. Based on IFMIF (International Fusion Material Irradiation Facility)-EVEDA (Engineering Validation Engineering Design Activities), the nitrogen-trapping loop was designed and fabricated at The University of Tokyo. Lithium in the...
Article
Hydrogen permeation window is a candidate not only as the tritium recovery device from liquid lithium, but also as the hydrogen isotopes monitor for molten lithium because hydrogen permeation rate is dominated by hydrogen concentration. In this study, changing tritium concentration in lithium, tritium permeation through iron window contacting with...
Article
The self-diffusion coefficient of water, D , in proton exchange membranes (PEMs) based on crosslinked-polytetrafluoroethylene (cPTFE) films was measured by a radioactivated-tracer permeation technique using tritium labeled water (HTO). The D value was found to increase with the water volume fraction of the PEM, φ , probably because the water-filled...
Article
Tritium permeation through erbium oxide coatings has been modeled on the basis of experimental results. Permeation models were constructed step-by-step by the introduction of the following predominant parameters: surface coverage, grain size, and energy barrier. The surface-coverage model agreed with the imperfectly coated samples fabricated by fil...
Article
Full-text available
Suppression of tritium permeation through structural materials is essential in order to mitigate fuel loss and radioactivity concerns. Ceramic coatings have been investigated for over three decades as tritium permeation barriers (TPBs); however, a very limited number of investigations on the mechanism of hydrogen-isotope permeation through the coat...
Conference Paper
An anode microstructure controlled solid oxide fuel cell was successfully fabricated by low temperature process and the maximum power density of the cell was 33 mW/cm(2) at 600 degrees C. The LSGM electrolyte thin film was available by post-annealing at 1000 degrees C after deposition using radio frequency magnetron sputtering. Thus, the sintering...
Article
Full-text available
Japan-US cooperation program TITAN (Tritium, Irradiation and Thermofluid for America and Nippon) started in April 2007 as 6-year project. This is the summary report at the midterm of the project. Historical overview of the Japan-US cooperation programs and direction of the TITAN project in its second half are presented in addition to the technical...
Article
Oxygen isotope exchange and time-of-flight secondary-ion mass spectroscopy were used to visualize the oxygen pathway in a silver cathode for solid-oxide fuel cells. (18)O was electrochemically transferred into the electrolyte through the silver cathode and immobilized by quenching. The three-dimensional distributions of (16)O, (18)O, (107)Ag, (109)...
Article
Y2O3 insulating coating is under development to mitigate the MHD pressure drop in Li blanket system. The problem in the development is that Y2O3 coating forms LiYO2 in high temperature Li and properties of LiYO2 are not investigated. In this study LiYO2 was synthesized by two methods to research its characteristics. XRD analysis shows pure LiYO2 ca...
Article
The development of a tritium permeation barrier is essential for building a tritium recovery system in fusion power plants. Toward realizing this application, the fabrication of erbium oxide coatings by metal-organic decomposition has been carried out on reduced activation ferritic/martensitic steels. The coated samples exhibit different surface st...
Conference Paper
In order to deepen the insight into water transport in polymer electrolyte membranes (PEMs), we calculated the self-diffusion coefficient of water, D-W, by dissipative particle dynamics (DPD) simulation. The simulation target materials are a Nafion membrane and radiation-grafted PEMs in the fully-hydrated states. D-W was obtained by the following p...
Article
The possibility of the use of Ag as the electrode material of low-temperature operating solid oxide fuel cells and low-temperature operating solid oxide electrolysis cells was researched by compatibility of Ag with electrolyte materials point of view. When a high anodic-potential (≥300mV) is applied on a Ag electrode on a scandia-stabilized zirconi...
Article
The spent electrolyte arising from pyroprocessing should be recycled to reduce the volume of high-level radioactive waste. To establish the spent electrolyte process by a phosphate conversion method, a preliminary experiment that followed a thermodynamical approach and used an electric furnace under argon gas atmosphere was carried out. The results...
Article
Full-text available
Transuranic elements have been simultaneously electro