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

to operation of iteR. solutions for controlling elms that are consistent with iteR constraints
are particularly critical, owing to predictions that unmitigated type i elms will ablate the divertor
targets at an unacceptable rate. control solutions for specific axisymmetric instabilities, resistive
wall modes, and neoclassical tearing modes must be developed and qualified with sufficient
reliability and performance to produce the required low level of disruptivity. axisymmetric control
solutions may also be required for the regulation of runaway electrons following a disruption.
Fusion Plant: certain limited elements of a power plant fuel and breeding cycle will be tested
in iteR, including test blanket modules (tbm) for breeding tritium. control requirements associated
with these elements include development of tbm operation control solutions and remote
maintenance solutions, possibly including accelerated access and replacement of major components
such as divertor cassettes.
handling off-normal events and faults in a safe, reliable manner
The success of iteR will critically depend on the control system’s ability to minimize the frequency
of off-normal events and to respond effectively to minimize damaging effects. a key part of
this solution is to demonstrate reliable control in the proximity of stability boundaries, including
excursions expected during nominal operation, as well as off-normal or fault-triggered excursions.
Reliable operation under nominally disturbed regimes (e.g., intermittent sawteeth, elms,
or transient magnetic island growth) falls under the research category in chapter 2. however,
novel algorithmic control and response solutions beyond nominal control are also required for excursions
requiring transient changes of the operating regime (e.g., response to loss of a diagnostic
channel or key actuator), rapid but controlled shutdown (e.g., identification of an impending unrecoverable
state), or emergency uncontrolled shutdown (e.g., identification of immediate unrecoverable
state and insufficient time for controlled shutdown, often envisioned as serving to mitigate
potential system damage). enabling elements of these solutions include a quantifiably reliable
systematic approach and corresponding integrated system for response to off-normal events
and fault-triggered excursions, real-time predictors for proximity to key operational limits, algorithms
and mechanisms for mitigating damage, and recovery/cleanup strategies to rapidly restore
plant availability. approaches must be developed to quantify performance and risk/probabilities
for licensing and certification.
Developing model-based control algorithms
design of model-based control algorithms requires both new computational tools as well as new
algorithmic approaches. computational tools are needed to produce control-level models, integrated
and sufficiently comprehensive simulations, and real-time predictive models for on-line
controller adjustment or operating regime identification. iteR will specifically require an integrated,
axisymmetric, resistive mhd simulation code for development and testing of controllers,
as well as pulse verification. verifying pulse consistency and performance is an operational requirement
of the present iteR control system specification. The models and simulations used for
these purposes must be thoroughly validated against data from operating devices.
These model-based control tools will require the development of new algorithmic approaches.
This research includes mathematical solutions for nominal high-performance control, as well as
50