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

tics. integrated control methods for simultaneous fueling regulation and burn control must also
be developed and demonstrated.
FuSiOn PLant
control requirements specific to fusion power plant operation include blanket operation, regulation
of output power across a wide range to match the grid load, supervisory control under sustained
duration conditions to ensure high availability and high reliability performance, and remote
maintenance control solutions. integrated blanket and plasma control must simultaneously
balance fusion power (plant output) requirements with blanket breeding efficiency requirements.
in particular, a blanket operation control solution must be developed consistent with power plant
requirements (breeding ratio [bR] must be regulated in a narrow region just above 1.0: bR[max]>
bR > 1.0, where likely bR[max]~ 1.05-1.1 to respect on-site tritium inventory limits). methods for
fusion output power regulation must be developed and demonstrated with high efficiency, stability,
and performance robustness for true sustained duration of many months without downtime.
StabiLity
high-performance power plants are often envisioned to operate in regimes (e.g., advanced tokamak)
very close to or beyond passive stability limits. Robust operation in such regimes requires
active and reliable stabilization of many instabilities including resistive wall modes, neoclassical
tearing modes (ntms), energetic particle modes, thermal instabilities, axisymmetric instabilities,
elms, and core “sawteeth.” For example, robustness to ntms may require suppression of
sawteeth as a seed for island formation, as well as preemptive current drive at resonant surfaces,
to raise the metastability threshold. Research requirements include developing and demonstrating
methods of passive and active RWm stabilization consistent with demo operation. edge localized
mode control solutions consistent with demo must be designed and demonstrated in relevant
steady-state plasmas.
development and experimental demonstration of control solutions for the highly constrained,
multivariable problem of burn regulation will be essential. an aRies-at-like demo would operate
in a nominally stable regime relative to thermal instability, but driven limit cycles or instabilities
from the coupled dynamic system must be prevented. The needs, mechanisms and control
solutions for fast-particle instability suppression must be determined, consistent with reactor requirements.
neoclassical tearing mode suppression scenarios and control solutions must be developed
for demo, consistent with reactor conditions and sustained duration. (a key question:
is suppression by electron cyclotron current drive achievable and consistent?) improved understanding
of ntm physics, effects of suppression mechanisms (e.g., localized current drive, profile
modification, sawtooth stabilization), experimental demonstration, and certification of performance
will all be required.
OFF-nORMaL EVEnt anD FauLt COntROL anD RESPOnSE
creating an attractive fusion power plant requires an integrated, comprehensive control solution
that provides high confidence operation with quantifiable reliability. a key part of this solution is
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