The steps beyond ITER are open at this stage. During the ITER construction and operation period, other magnetic confinement schemes or inertial fusion may show more promise than ITER, so the door is open for these schemes to supersede the tokamak in subsequent steps. Certainly, the technologies developed for and tested on ITER: remote maintenance, tritium breeding high temperature blankets, and high heat flux components, will provide essential information whatever the confinement scheme used.

The concept of the "fast track" to fusion power, should ITER continue to demonstrate that the tokamak line of magnetic confinement is the most promising for power generation, has recently been further elaborated in studies at EFDA and at Culham Laboratory. This approach is designed to speed up the development to the extent possible. It is designed around "pillars" of the programme - ITER, IFMIF, and existing large tokamaks - considered essential to further progress, as well as "buttresses" - e.g. a components test facility, and a new "satellite" non-nuclear tokamak to more rapidly study the implications of ITER physics - that can speed progress and reduce risks.

The programme that is evolving, in this ongoing work, is shown below (graphics by permission Prof. Sir Chris Llewellyn Smith, from his presentation at IAEA Fusion Energy Conference, Vilamoura, 2004):

The key part of this figure is shown below:

Such a plan shows why it will be very difficult to commission the first commercial-sized tokamak before 2050. However it could be that sufficient information is gained on the step beyond ITER (DEMO), through its staged operation, and it is sufficiently prototypical of the series production of power plants, that it will be possible to be more confident at an earlier stage concerning the economic viability of the first series of power plants produced.