Thermonuclear device

Neutrons are generated upon plasma combustion in a thermonuclear device, which are absorbed by toroidal coils to generate heat during not-combustion state. Since there is no thermal load, the amount of evaporated helium gas returned to a helium liquefying device is greately different between the combustion and non combustion states of plasmas and the helium liquefying device can not be operated stationarily. That is, when a full power operation is continued corresponding to the combustion state, the temperature of the helium liquefying device at the lower temperature portion is decreased since the thermal load is low in the incombustion state, which gives damages to an expansion turbine of helium liquefying device. In a large-scaled helium liquefying device, it takes a long time for switching form the full power operation to a reduced power operation to increase the plasma operation interval. Then, a heater is disposed to a supercritical helium heat exchanger vessel for compensating fluctuating thermal load. The operation efficiency of the thermonuclear device can be improved by keeping the helium liquefying device at a constant state. (K.M.)