The DIII-D Wall Change-Out Project*

The DIII-D program is embarking on a new mission to qualify integrated solutions for fusion that include reactor-relevant wall and divertor materials, moving away from the current bulk graphite wall. The facility aims to test high-priority plasma-facing materials emerging from the fusion materials research program and serve the needs of private sector fusion pilot plant developers. The full wall/divertor change out, expected to occur in 2027, will guide the implementation of other upgrades (e.g., staged divertor shaping and additional RF heating). We have launched a community-wide consultation process to consider scientific needs and identify options. This process has already raised significant questions, notably a debate between traditional refractory metals (e.g. tungsten) or more innovative alloys, high-temperature ceramics (e.g. SiC), or even liquid metals (e.g. lithium). The relative potential of these approaches to address the key research gaps identified in recent community reports and align with the overall DIII-D/DOE-FES missions, as well as required hardware/engineering/diagnostic resources, are being evaluated. Once FES has decided on the approach, we will pursue a Physics Validation Review (PVR) in the fall of 2024; current PVR progress will be presented.