Perspective of a Reversed Field Pinch as Fusion Core for Neutron Generation

The operation of RFX-mod, the largest Reversed Field Pinch (RFP) experiment, with plasma currents up to 2 MA demonstrated a substantial increase of the electron and ion temperatures versus the plasma current. The observed trend outlines a path toward a significant D-T fusion process yield in larger devices with higher plasma current [1]. Such a device, in which the plasma is purely ohmically heated, could act as an efficient, robust and cheap fusion neutron source with a neutron rate to be used as the basis for a Fusion-Fission Hybrid Reactor (FFHR). Its peculiar features can be summarized as: ohmically heated plasma, toroidal field winding rated for a very low magnetic field (two orders of magnitude lower than in tokamaks), robust and cheap construction, simple access for Remote Handling and easy maintenance. The neutron production, as required in a hybrid reactor, is guaranteed by a continuously pulsed operation without the need of additional current drive systems. A realistic concept consist of an inductively operated RFP with major radius R=6 m, minor radius a=1 m and a current of 20 MA. The expected plasma temperature would be in the range 10-15 keV, leading to a neutron production rate in the range of 1019 n/s and a wall neutron load of 0.2 MW/m2.