Discussion About the Size of a Future Fusion Demonstration Reactor: The Impact of the Toroidal Magnetic Field

In parallel to ITER preparation, power plant conceptual studies have been carried out in Europe as a guideline for the main design parameters of a fusion demonstration reactor, the construction of which is scheduled to start twenty years hence. A key component of this fusion demonstration reactor is the superconducting magnetic system, which represents in ITER 30% of the investment cost. A high toroidal confinement field B_t, can help to moderate the major radius of the tokamak, and thereby the investment cost of the machine. Two versions of such a demonstration reactor, with different values of B_t will be compared in terms of volume, radial extension for the toroidal field magnet inner leg, central solenoid available flux swing and investment cost.