The JET tokamak, in operation since 1983, has provided important results which give a high degree of confidence in the feasibility of magnetic fusion reactor physics. JET, for instance, has proven the principle of plasma self-heating by fusion reactions. However, in steady state only about 18% of the total power needed to maintain the plasma at the required temperatures was provided by these reactions, the rest was supplied externally. In ITER, as in future fusion power plants, self-heating of the plasma will be the dominating effect.

ITER’s aim is to confirm and optimise the physics of the future reactor and to demonstrate the technological feasibility of magnetic fusion power. Key technologies, such as the tritium fuel cycle and remote handling, will be extensively used in ITER, and it will be of paramount importance to demonstrate the viability of such techniques with an adequate degree of reliability.