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

large-scale process control problem, as well as a significant extension beyond present devices and
iteR.
development of fusion science and technology has been paced (in many cases enabled) by developments
in advanced control solutions, usually implemented in operating fusion devices. Present
research programs and presently operating devices have already produced general solutions for
some of the control problems expected to face iteR. Given sufficient support, they are expected
to identify most or all of the remaining needed solutions before iteR operates. such programs
are already exploring some issues expected to occur in demo, but it has been long recognized
(and specifically identified as a gap in the Priorities, Gaps and opportunities Report) that present
worldwide plans for fusion development do not provide the means to solve many of the control
problems in demo (or an eventual commercial reactor). While many ideas to address the gaps exist,
enhanced research is required.
The research required to establish the basis for control of demo will involve expanding the frontier
of advanced mathematical algorithms for the unprecedented complexity of the fusion reactor
control problem. This core effort necessitates specific forms of physics understanding, often
uniquely driven by control requirements. Physics understanding in turn enables development of
new models for all relevant plasma and auxiliary systems that are an appropriate balance of accuracy
and computational tractability. breaking the new ground required in this field and reducing
fusion power plant control to practice will require decades of effort, highly coupled with the many
elements of fusion science and technology development. While present devices and research have
begun this effort in limited ways, the revolutionary solutions required for demo imply a need to
begin an accelerated and systematic research activity soon. because present and near-term devices
are beginning to explore regimes with highly coupled nonlinear complexity, this accelerated effort
will have an immediate impact on the experimental fusion program.
gEnERaL COntROL RESEaRCH gaPS anD nEEDS FOR DEMO
The sections following describe individual areas with identified research gaps and requirements.
however, all of these research areas in fusion plasma control share certain common requirements.
model-based control requires validated control-level models for design of relevant systems in
active control or detection and response loops. sufficiently detailed simulations and associated
models must be developed to verify both controller performance and implementation prior
to use. Control algorithm design approaches and solutions must be created for each area, in
many cases requiring additional mathematics and algorithmic understanding at or beyond present
frontiers in the control field. Real-time computational solutions are required for analysis
and interpretation of plasma and plant state (e.g., real-time analysis and prediction of proximity
to stability boundaries) as well as implementation of complex control algorithms. in many cases
new control actuators and diagnostics must be developed with the necessary effectiveness, dynamic
performance, and accuracy. Experimental demonstrations of control schemes and specific
controllers in relevant environments (sustained duration, neutronics, relevant actuators and
diagnostics, operating regimes, etc.) will be essential. The ability to quantify reliability of control
performance for a reactor (including nominal operation, response to faults, and probability
of fault scenarios) will be required to meet nuclear and licensing constraints. in many cases im-
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