Aspects of superconductive energy storage systems for supply of fusion magnets

The demand of pulsed power for fusion reactors and the method of supplying the pulsed power are discussed. The requirements for energy and power are as follows. The energy requirement is 5 x 109 Ws, the time step is several seconds, and the apparent power is 109 VA. An established technique to supply the pulsed power demand of fusion magnets is the use of flywheel motor-generator sets supported by the grid. There exist different indications that superconducting energy storage units with capacitive acting machines or converter can become a more attractive alternative. One constraint is the high voltage technology to be applied for such storage coils, especially its influence on costs and reliability. The main fields of problems which had to be solved and handled were material properties at high voltage, component design at high voltage, testing methods, the quench protection of coils at high voltage and transient behavior in components. Discussions about these problems are presented in this paper. (Kato, T.)