MEST Multicoil System Control and Application Study to a PILOT FFHR With an RFP Fusion Core

The magnetic energy storage and transfer (MEST) system is a newly developed scheme to supply the superconducting (SC) coils in large-size tokamak and reversed field pinch (RFP) reactors to cope with the issues related to electrical power handling in these applications. It is a very promising alternative to face both the issues related to high active power peaks, required during plasma formation and control, and the huge reactive power demand, linked to the use of thyristor converters. The MEST system operating principle and control strategy supplying a single SC coil have already been outlined and studied in previous works. From this starting point, the MEST control system has been expanded to supply a complete set of SC poloidal field coils, considering the magnetic coupling and the energies associated with the magnets-plasma system, essential to control the overall system energy and achieve a certain degree of decoupling between the grid and the coils. This article presents and discusses the principles of controlling the currents of a complete set of poloidal field coils using the MEST system with efficient electrical power management. The application study to PILOT fusion–fission hybrid reactor (FFHR) is reported using analytical calculations and numerical simulations to assess the control operation.