Scenario feasibility and plasma controllability for Volumetric Neutron Source (VNS)

To test the efficiency of the blanket modules in a DEMO compliant environment, EUROfusion is considering the realization of a Volumetric Neutron Source facility (VNS). VNS will be a compact device, equipped with a DEMO-scale breeding blanket, pushing the active coils and the passive structures away from the plasma. From the electromagnetic viewpoint, this results in: the increase of the coils current needed for the definition of the plasma scenario; a reduction of the plasma shape controllability; the limitation of the stabilizing effect of the passive structures. To tackle these problems, the PMU is investigating two main design options: 1) Window-frame coil configuration 2) PF-in-TF configuration. In this paper, an electromagnetic analysis of the two design options in terms of plasma scenario feasibility and plasma controllability is proposed.