Gifu, Japan
Gifu, Japan

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Tanaka M.,Japan National Institute for Fusion Science | Katahira K.,Tyk Co Inc. | Asakura Y.,Japan National Institute for Fusion Science | Ohshima T.,Tyk Co Inc.
Solid State Ionics | Year: 2010

In a nuclear fusion plant, the development of hydrogen processing technologies is an important issue since hydrogen isotope gas must be utilized as fuel. High-temperature proton conductors are favorable materials for hydrogen processing systems in nuclear fusion engineering. Possible applications of proton conductors include hydrogen pumps and hydrogen sensing. For one of these protonic functions, we have proposed applying a hydrogen pump to hydrogen recovery in the hydrogen processing system. In this paper, as a feasibility study, a one-end closed tube of SrZr0.9Yb0.1O3 - α proton conductor was evaluated as a hydrogen pump at elevated temperatures. As a result, hydrogen gas could be extracted from a mixture of gases including hydrogen, water vapor and methane, simulating the gases present during hydrogen processing in a fusion device, while methane and water vapor could be decomposed to hydrogen gas on the platinum electrode. This result indicates that a hydrogen pump using a proton conductor is quite useful in the hydrogen recovery system for the exhaust gas of a fusion device. © 2009 Elsevier B.V. All rights reserved.

Tanaka M.,Japan National Institute for Fusion Science | Ohshima T.,Tyk Co Inc.
Fusion Engineering and Design | Year: 2010

The characteristics of electrochemical hydrogen pump using one-end closed tube type BaZr0.955Y0.03Co0.015O 3-α, which has higher proton conductivity among other zirconate series proton conductor at the intermediate temperature, were demonstrated by a direct current method in the temperature range from 623 to 873K. Under water vapor electrolysis condition, mixed proton and electron-hole conduction were exhibited and proton transport number was decreased less than 0.37. On the other hand, under hydrogen pumping from a mixture gas contained with hydrogen gas, proton transport number has attained more than 0.85. However, not only proton and electron-hole conductions but also oxide-ion conduction was exhibited even at lower temperature below 700K. Thus, the growth of electrochemical failure induced by oxide ion migration was observed. From the standpoint of high proton transport number and low oxide-ion conduction, a candidate proton conductor for nuclear fusion engineering applications was proposed to compare with hydrogen pump characteristics among the zirconate series proton conductor. © 2010 Elsevier B.V. All rights reserved.

Kondo M.,Japan National Institute for Fusion Science | Kondo M.,Graduate University for Advanced Studies | Muroga T.,Japan National Institute for Fusion Science | Muroga T.,Graduate University for Advanced Studies | And 7 more authors.
Journal of Nuclear Materials | Year: 2011

The compatibility of reduced activation ferritic steel, JLF-1, was investigated by the corrosion tests in static lithium (Li), impeller induced Li flow and thermal convection Li. A simple model for corrosion of JLF-1 in Li was based on the equation of mass transfer and mass balance in the corrosion test. Solubility of Cr in Li was evaluated as 37.6 wppm at 500 °C and 77.2 wppm at 600 °C based on the data obtained in corrosion tests in static Li. The mass transfer coefficient of the dissolved Cr from the steel in static Li was experimentally determined to be 4.08 × 10-8 m/s at 500 °C and 1.81 × 10-7 m/s at 600 °C. The mass transfer coefficient for impeller induced flow calculated from Sherwood number and literature value of the diffusion coefficient was 1.34 × 10-4 m/s at 500 °C and 1.40 × 10-4 m/s at 600 °C. Theoretical values for the corrosion loss were compared with values obtained from the experimental data. The mass transfer coefficient determined for the thermal convection loop was 1.73 × 10-5 m/s. © 2011 Elsevier B.V. All rights reserved.

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