Tungsten lattice structures for DEMO plasma limiters

Persistent research on thermonuclear magnetic confinement fusion has led to current design activities regarding a demonstration fusion reactor (DEMO). One predominantly challenging issue with respect to the realisation of a DEMO reactor is the design and manufacture of highly loaded plasma-facing components (PFCs) that have to sustain intense particle, heat and neutron fluxes during fusion operation. A particularly critical aspect with respect to PFCs in a DEMO reactor are transient wall loadings that can e.g. arise due to plasma instabilities in a tokamak. Such transient events can lead to very intense heat loadings (several tens of GW/m^2 for time periods of a few ms) on PFCs that in turn can damage the blanket structures of a reactor severely. In order to protect the wall of a fusion reactor against such events specific limiter PFCs are currently being investigated. These components are foreseen to baffle the short and intense heat pulses to the reactor walls in order that blanket structures behind these limiter components are not thermally overloaded or damaged. A possible material solution for such limiter PFCs is the use of tailored porous tungsten (W) materials. With such metamaterials, components can be realised that combine an overall low thermal conductance due to the incorporated porosity with the beneficial plasma-wall interaction properties of W.The talk will give an overview regarding the context in which the development of the abovementioned limiter components is currently being performed in the framework of EUROfusion DEMO activities. Furthermore, it will be presented how IPP is involved in these activities through the fabrication and investigation of tailored anisotropic W lattice structures that are fabricated by means of additive manufacturing.