20d Development of novel mesoporous substrates for a stable liquid-metal plasma-material interface under ultra long-pulse plasmas

A daunting challenge facing future plasma burning fusion reactors are the extreme conditions plasma facing components are exposed to. Extreme particle and heat fluxes exceeding 10-20 MW/m2 drive traditional material surfaces out of equilibrium and induce topographical and compositional changes that can have deleterious effects on the plasma edge and, ultimately, fusion plasma confinement. Processing of refractory alloys is challenging, and it is uncertain if solid plasma facing components are a viable option for future fusion reactors. Plasma facing components coated in liquid metal (lithium) offer highly desirable properties that can address these issues. The approach combines advanced manufacturing technologies of both bulk tungsten and its surface to create a hybrid tungsten-liquid lithium material system that can survive and operate continuously in the extreme fusion environment without disturbing the fusion reaction. Phase I & Phase II work thus far has demonstrated the feasibility of small-scale manufacturing and use of fine-grain mesoporous tungsten in the HIDRA research fusion reactor with liquid lithium. Survival of the material, particle interactions with liquid lithium, and enhanced wetting have been demonstrated. Significant increases in plasma temperature and density due to lithium interactions have been observed. These benefits demonstrate that using the technology in a commercial fusion reactor would drastically reduce cost. Phase IIB will build on this success by address two remaining key aspects of the tungsten technology: scaling manufacturing and determining mechanical properties. Scaling is necessary to demonstrate manufacturing feasibility and to perform future testing in prototype commercial fusion reactors. Defining mechanical properties will enable component design and help estimate component lifetime. As the market for PFCs is not yet established, Phase IIB will demonstrate the tungsten-lithium system in a high-temperature heat pipe for near-term hypersonic vehicles to accelerate development and ensure readiness for commercial fusion reactors. Phase IIB development will deliver high-temperature heat pipes to provide advanced cooling solutions for hypersonic vehicles in the near term. The advances made in Phase IIB combined with early deployment in heat pipes will ultimately enable high-temperature radiation-resistant materials for plasma-facing components and contribute to the success of fusion energy. Fusion is