Current status and critical issues for development of SiC composites for fusion applications

Current status and recent research achievements in SiC/SiC composites

Tritium/hydrogen barrier development

Silicon carbide composites as fusion power reactor structural materials

Extensive progress and improvements have been made in the science and technology of gamma titanium aluminide alloys within the last decade. In particular, our understanding of their microstructural characteristics and property/microstructurc relationships has been substantially deepened. Based on these achievements, various engineering two-phase gamma alloys have been developed and their mechanical and chemical properties have been assessed. Aircraft and automotive industries arc pursuing their introduction for various structural components. At the same time, recent basic studies on the mechanical properties of two-phase gamma alloys, in particular with a controlled lamellar structure have provided a considerable amount of fundamental information on the deformation and fracture mechanisms of the two-phase gamma alloys. The results of such basic studies are incorporated in the recent alloy and microstructure design of two-phase gamma alloys. In this paper, such recent advances in the research and development of the two-phase gamma alloys and industrial involvement are summarized.

Gamma Titanium Aluminide Alloys

Optimization of OH coil recharging scenario of quasi-steady operation in tokamak fusion reactor by lower hybrid wave current drive

Blanket–plasma interaction in tokamaks: Implication from JT-60U, JFT-2M and reactor studies

Analytical and experimental evaluations of simulated sweeping heat load on the divertor plate for ITER

PROBLEM TO BE SOLVED: To solve problems in a vacuum evacuating system for a nuclear fusion reactor that the pumping system is upsized, heat is generated on a cryogenic adsorption surface by the irradiation of high energy radiations caused by nuclear fusion reaction in a conventional vacuum evacuating system using a cryopump, and that extra refrigerating energy is required, since extra exhaust velocity is imposed on a high vacuum pump in order to exhaust gaseous impurities for radiation cooling in a diverter part. SOLUTION: In this vacuum evacuating system for a nuclear fusion reactor, metal is turned into a liquid metal by heating it to its melting point or higher. Vapor of the liquid metal is jetted out of a narrowed-down nozzle into a vacuum space at a subsonic to supersonic velocity. Gaseous molecules and atoms caught up in a jet flow of the metal vapor are given unidirectional kinetic momentum to compress, pressurize, and transfer the gaseous molecules and atoms. The temperature and pressure of the metal vapor jetted out from the nozzle are changed in conformity to the operation conditions of the fusion reactor. COPYRIGHT: (C)2004,JPO

Vacuum evacuating system for nuclear fusion reactor

Considering the geometrical characteristics of tokamak reactors with low aspect ratio, a basic neutronics strategy was derived to construct the inboard structure mainly for neutron shielding and produce enough tritium in the outboard blanket. The designs for optimal inboard shield were surveyed and necessary thickness was estimated to make the neutron flux low enough on the super-conducting magnet. In addition, the outer blanket designs were studied to attain the tritium breeding ratio (TBR) large enough for a self-sustaining fusion reactor on the basis of the advanced fusion reactor materials.

Satoshi Nishio

Papers

Optimization of OH coil recharging scenario of quasi-steady operation in tokamak fusion reactor by lower hybrid wave current drive

Blanket–plasma interaction in tokamaks: Implication from JT-60U, JFT-2M and reactor studies

Analytical and experimental evaluations of simulated sweeping heat load on the divertor plate for ITER

Vacuum evacuating system for nuclear fusion reactor

Neutron Shielding and Blanket Neutronics Study on Low Aspect Ratio Tokamak Reactor