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

chemical interactions between the structural materials and other materials in a power system,
such as corrosion of the structural materials by the coolant, oxidation in gaseous environments,
mass transfer within the system via the coolant, and interaction with tritium breeders, must be
determined and understood. also, the impact of such phenomena on design and performance
of the fusion power system must be assessed. determinations of what chemical interactions are
potentially important, understanding the chemical thermodynamics and kinetics, and providing
the basic information for design studies are needed. This research requires specialized facilities
such as high-temperature gas reaction systems for oxidation studies, thermal convection and small
pumped loops to investigate corrosion and mass transfer phenomena with liquid metal coolants
and, in some instances, specialized mechanical test systems to investigate dynamic effects of
chemical interactions on mechanical properties. The selection and development of materials
must be carefully integrated with efforts in Fusion nuclear science and technology (Theme 3 and
Thrust 13) through which the program will address the complex and often competing performance
requirements for materials.
central to successful deployment of fusion power systems is development of large-scale fabrication
and joining technologies. a promising new alloy class, known as nano-structured (dispersion
strengthened) ferritic alloys has recently been developed. These materials contain an ultrahigh
density of nanometer-scale, non-equilibrium, enriched phases that may impart unprecedented
high-temperature creep strength, radiation damage resistance, and efficiently trap he. however,
large-scale fabrication and joining technologies that would enable construction of large geometrically
complex components and structures from these materials do not exist. to exploit these
promising materials, development of such technologies is essential. a partnership with industry
to take advantage of large-scale fabrication and joining capabilities and experience is needed to
make progress in this area.
Finally, a key challenge is development of high-performance materials that will ensure the economic
attractiveness of fusion power plants while simultaneously achieving safety and environmental
acceptability goals. Radioactive isotope inventory and release paths are important considerations
in designing for safety. development of low or reduced activation materials is central to
ensuring that materials removed from service are recyclable and/or clearable, and will not require
long-term geological disposal, thereby minimizing the impact on the environment. This will be
primarily accomplished by reduction of impurities that restrict the free release of in-vessel components.
Develop and experimentally validate predictive models describing the behavior and lifetimes of
materials in the fusion environment.
new materials must be discovered to make fusion a technically viable and economically attractive
future energy source. The most efficient approach to materials discovery is a science-based effort
that closely couples development of physics-based, predictive models of materials behavior with
key experiments to validate the models. materials degradation in the fusion neutron environment
is an inherently multi-physics, multi-scale phenomenon. models describing neutron irradiation
damage processes in fission and fusion nuclear systems have been under development for
many years. Figure 1 shows molecular dynamics simulations demonstrating that high-energy fu-
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