Abstract
Every existing gas turbine is of open-cycle in which exhaust gas is discharged into atmosphere. Several exceptions, namely those of open-cycle, all disappeared so far, because there has been no demand for that. Therefore, the effort of gas-turbine development has been directed towards simple enhancement of the inlet gas temperature through material development and/or some exquisite blade cooling technique. In the field of nuclear energy, on the other hand, there exists a demand of closed-cycle for the next generation reactors such as high temperature gas-cooled power reactor or gas-cooled fusion reactor for which the perfect confinement of radioactivity is the crucial requisite. Moreover, in the nuclear applications, the highest temperature of the gas turbine cycle is restricted from above by other factors such as integrity of irradiated materials or possible mobility of the radioactivity. If so, the problem inevitably reduces to that of how to realize the excellent cycle performance through other thermo-mechanical considerations
