Research Needs for Magnetic Fusion Energy Sciences - US Burning ...

sion damage events (red atoms) are similar to multiple, lower-energy events (green atoms), which
permits fission-fusion damage scaling. however, the fusion irradiation environment is very complex
due to displacement damage from high-energy neutrons, bombardment of the surface by energetic
ions and concomitant high concentrations of damaging he and h from nuclear transmutation
reactions, as well as surface modification by interactions with the plasma. beyond the fusion
nuclear environment, the materials, components and structures of a power system will be
exposed to severe thermo-mechanical loads and aggressive chemical species. The current fusion
materials theory, modeling and simulation effort needs to be significantly expanded at all spatial
and temporal scales to address the following needs:
• computationally efficient and physically robust interatomic alloy potentials, which
account for directional bonding, magnetism and charge transfer (to accurately describe
complex multi-component, multi-phase materials).
• advanced large-scale, atomistic models that describe the very large number of material
parameters and processes that interact in complex ways to control the migration,
interaction, and accumulation of defects and gases, as well as the non-equilibrium
rearrangements of solute constituents by segregation and phase transitions (to predict
nanoscale evolutions in complex materials for both processing and extended service).
• linked atomistic, mesoscopic, and continuum deformation and fracture models (to
predict hardening, plastic instabilities, transitions from ductile-to-brittle and creep/
creep rupture behavior for complex materials and loading conditions).
• large-scale structural models that integrate all degradation phenomena (needed for
virtual integrated testing and materials-component development).
establish a fusion-relevant neutron source to enable accelerated evaluations of the effects of
radiation-induced damage to materials.
to become economically viable, in-vessel fusion power systems will require structural materials
with lifetimes approaching 200 displacements per atom (dpa). Recent fusion materials research
and development efforts have led to the development of RaF/m steels with good resistance to irradiation
in fission reactors for doses up to about 30 dpa. however, their performance in a high-
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Figure 1. Molecular dynamics simulations demonstrating
that high-energy fusion damage
events (red atoms) are similar to multiple, lower-energy
events (green atoms), which permits
fission-fusion damage scaling.