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

ased materials development with advanced design is required. specific areas of study would include
Pmi testing of adaptive materials compatible with coupling of the plasma-surface boundary
and an aggressive nuclear environment. concepts can include low-z/high-z alloys or nanocomposites
(e.g., boron or silicon with tungsten), solid flow-through materials (e.g., carbon) and
refractory ultracrystalline thin-film coatings. Furthermore, needed are a detailed mechanistic
understanding and development program for refractory materials including tungsten, extending
the irradiation and temperature performance of advanced nano-composite steels, and a definition
of the absolute design lifetime limits of copper alloys.
such a materials-science-based development needs to be closely integrated with a vigorous material
design effort, which is the role of Thrust 14. careful coupling of the material design effort
with material testing will be required to advance a science-based development approach. The
changes and interaction of the newly proposed materials will be examined for compatibility with
the strongly coupled plasma-surface boundary in this Thrust. such testing will need to proceed in
a timely and cost-effective manner to ensure that the results are incorporated into improved material
designs that will enhance the performance of the developed materials. Furthermore, design
advances will require materials that are radiation-tolerant and provide adaptive materials surfaces
that can operate in a burning plasma environment. Providing a facility that can both test for
plasma and radiation (i.e., neutrons, etc.) damage will provide a unique opportunity to test advanced
materials under simulated, burning plasma reactor-relevant conditions.
Facilities for examining materials exposed to high levels of neutron exposure are limited. For the
high-dose, high-temperature materials of particular interest here, the lack of a high-flux 14 mev
neutron source will prove a critical obstacle. While ion beam and fission reactor sources of damage
are currently available and should be exploited, neither are able to yield the appropriate ratio of
atomic displacement damage to transmutation helium production that will occur for the sample
sizes required for meaningful component characterization. Therefore, options for a large-volume,
fusion-relevant neutron source should be evaluated.
Relationship to Ongoing PSi Research
This R&d approach has the potential of establishing a broad understanding and predictive capability
of the fundamental processes and their synergistic interactions, which in turn advances
theory, modeling and simulation of these processes in fully toroidal configurations. This approach
for Psi research, on the other hand, does not intend to address physical phenomena related to the
interacting toroidal plasma outside the last closed flux surface in the toroidal configuration.
The new Psi facilities envisioned here will complement and extend the capabilities of current Psi
research facilities, provide new research opportunities to the broader materials community, and
promote Us competitiveness in this area. These facilities are foreseen to be user facilities whose
design will be developed through Psi and fusion community participation. The upgrade of domestic
testing facilities, and the education and training of operating personnel, are critical to ensure
the development of a sound Psi basis for demo.
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