Impact of energetic fusion products on the first wall of a GenF's ICF reactor

GenF is developing an accelerated pathway toward a direct-drive inertial confinement fusion (ICF) reactor, aiming to provide safe, virtually unlimited, and carbon-free energy. As part of the TARANIS project, GenF collaborates with French research institutions (CEA and CNRS) as well as with international partners to address the critical problems in ICF physics.

One of the challenges is the design of the ICF reaction chamber, particularly the first wall (FW) components. The FW material is subjected to intense, pulsed emissions of X-rays, ions, and neutrons resulting from fusion reactions. Following ignition, the energy is distributed among ions- deuterium, tritium, helium and elements from the target's outer layers such as hydrogen and carbon.

This study presents simulations of physical sputtering, bulk damage, and compositional changes in various candidate FW materials induced by energetic ions, taking into account their energy distribution and spectra based on a typical target design by CEA for the TARANIS project. The FW lifetime is evaluated for tungsten, tungsten carbide, lithium fluoride, stainless steel, and graphite—with considerations of wall thickness and chamber geometry. Numerical simulations using the FESTIM code were conducted to analyze transient heat transfer in tungsten. Coupled modeling enabled the first evaluation of tritium accumulation and diffusion in tungsten under ICF-relevant thermal conditions, excluding displacement damage and material compositional changes.