Chemical and depth functionality in deuterium irradiated porous tungsten/liquid Li PFC system*

One challenge to plasma-burning fusion reactors is discovery and development of a material system, that balances bulk damage and surface response, that is not only resistant to the heat and particle fluxes but can adapt and evolve under the extreme conditions. A porous tungsten-liquid metal hybrid system is a potential balance between favorable bulk W properties while scaffolding for a liquid metal (LM) protecting from high-Z emission.  Overall design combines LM self-healing properties to delay the mechanical failure and to protect the structure via radiative vapor shielding. With advances in additive manufacturing, hierarchical designs can be achieved with different materials/properties emphasized based on relevant mechanisms occurring within the material and providing optimal functionality through the structure. Porous W-substrates have been fabricated, with PMI and micro-hydraulic testing, such as enhanced Li wetting. Micron-scale Li percolation during exposure to D plasma has been observed using ERD.  The synergistic behavior of the D relative to the Li during this exposure is characterized with in-operando NRA and post-mortem SIMS. Differing chemical complexes of D/Li/O/C due to W surface structure is observed with in-situ XPS.