Kyushu University · Materials Science
Professor Kazunari Katayama's research lab focuses on tritium behavior and confinement in fusion energy systems, particularly in advanced materials for tritium breeding and permeation barrier applications. The lab investigates hydrogen and tritium transport properties in ceramics such as Li₂TiO₃, alumina (Al₂O₃), and zirconium, with an emphasis on material performance under high-temperature and irradiation conditions. Key research directions include permeation behavior, isotope exchange reactions, and the development of multilayered structures to enhance tritium retention and safety in fusion reactors like DEMO. The lab also studies the long-term stability and gas release characteristics of plasma-facing materials such as tungsten and graphite.
Figures are computed from collected data and may differ slightly.
Tritium production utilizing nuclear reactions by neutron and lithium in a high-temperature gas-cooled reactor is attractive for development of a fusion reactor. From viewpoints of tritium safety and recovery efficiency, tritium confinement is an important issue. It is known that alumina has high resistance for gas permeation. In this study, hydrogen permeation experiments in commercial alumina tubes were conducted and hydrogen permeability, diffusivity and solubility were evaluated. By using ob
AbstractIt is important to evaluate tritium behavior in tungsten deposition layers considering a long-term plasma operation. In this study, tungsten deposition layers were formed by deuterium or helium RF plasma sputtering. The release behavior of deuterium or helium from the layers were observed by a thermal desorption method. When a tungsten deposition layer does not contain oxygen, the retained deuterium is mainly released as D2. When oxygen exists in the layer, the majority of deuterium is r
The approximate estimation of tritium permeation rate under the acceptable assumption from a safety point of view is surely useful to progress the design activities for a fusion DEMO reactor. Tritium permeation rates in the blanket and the divertor were estimated by the simplified evaluation model under the recent DEMO conditions in the water-cooled blanket with solid breeder as a first step. Plasma driven permeation rates in tungsten wall were calculated by applying Doyle & Brice model and gas
The pebbles of Li2TiO3 with excess Li, which is in a developmental stage in JAEA (Japan Atomic Energy Agency) as an advanced tritium breeding material, were exposed to water vapor at elevated temperatures. In the temperature rising process from room temperature to 900°C, pore distribution and BET surface area were largely changed. The surface area decreased gradually by a sintering effect when maintained at 900°C for a long time. The release of water vapor was observed at about 450°C by the deco
To launch a fusion reactor stably, it is necessary to prepare sufficient amount of tritium by an external tritium source. Tritium production using nuclear reactions by neutron and Li in a high temperature gas-cooled reactor (HTGR) is an attractive method. An important issue is tritium confinement in high temperature conditions of HTGR. Covering Li compound by Al2O3 is a promising method because hydrogen permeability in Al2O3 is quite low. Furthermore, it is expected that inserting Zr between Li
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