TACTICAL (sentence-level): - Strengthened verb choices (fail/prove vs. cannot/can) - Removed weak constructions (can be/may be → is/are) - Improved topic-stress positioning - Enhanced parallel structure in lists - Tightened passive constructions where appropriate OPERATIONAL (paragraph/section): - Improved transitions between subsections - Strengthened flow from transitory → stabilizing → expulsory modes - Enhanced coherence in formal methods discussion - Better linkage between HARDENS and dL subsections - Clearer progression in continuous controller classification STRATEGIC (document-level): - Sharpened Heilmeier question answers throughout - Improved section-to-section linkages - Strengthened research contribution clarity - Enhanced motivation for methodology choices - Better alignment of conclusions with next section openings
70 lines
3.9 KiB
TeX
70 lines
3.9 KiB
TeX
% GOAL PARAGRAPH
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This research develops autonomous control systems with mathematical guarantees of safe and correct behavior.
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% INTRODUCTORY PARAGRAPH Hook
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Nuclear reactors require extensively trained operators who follow detailed written procedures. Plant conditions guide operator decisions when they switch between control objectives.
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% Gap
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Small modular reactors face a fundamental economic challenge: per-megawatt staffing costs significantly exceed those of conventional plants, threatening viability. To remain competitive, these reactors need autonomous control systems that manage complex operational sequences safely without constant supervision while providing assurance equal to or exceeding that of human-operated systems.
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% APPROACH PARAGRAPH Solution
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We combine formal methods from computer science with control theory to
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build hybrid control systems that are correct by construction.
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% Rationale
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Hybrid systems mirror operator decision-making: discrete
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logic switches between continuous control modes. Existing formal methods
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generate provably correct switching logic but fail to handle continuous dynamics
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during transitions. Control theory verifies continuous behavior but
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fails to prove discrete switching correctness.
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% Hypothesis and Technical Approach
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Three stages bridge this gap. First, we translate written
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operating procedures into temporal logic specifications using NASA's Formal
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Requirements Elicitation Tool (FRET). FRET structures requirements into scope,
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condition, component, timing, and response elements. Realizability
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checking identifies conflicts and ambiguities before implementation.
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Second, reactive synthesis generates deterministic automata provably
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correct by construction.
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Third, we design continuous controllers for each discrete mode using standard
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control theory and verify them through reachability analysis. We classify continuous modes by their transition objectives. Assume-guarantee contracts and barrier certificates prove that mode transitions occur safely. This approach enables local verification of continuous modes
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without requiring global trajectory analysis across the entire hybrid system. We demonstrate this methodology on an
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Emerson Ovation control system.
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% Pay-off
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This autonomous control approach can then manage complex nuclear
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power operations while maintaining safety guarantees, directly addressing the economic constraints threatening small modular reactor viability.
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% OUTCOMES PARAGRAPHS
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If this research is successful, we will be able to do the following:
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\begin{enumerate}
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% OUTCOME 1 Title
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\item \textit{Synthesize written procedures into verified control logic.}
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% Strategy
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We will develop a methodology for converting written operating procedures
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into formal specifications. Reactive synthesis tools generate
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discrete control logic from these specifications.
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% Outcome
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Control engineers generate mode-switching controllers from regulatory
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procedures with minimal formal methods expertise, reducing barriers to
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high-assurance control systems.
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% OUTCOME 2 Title
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\item \textit{Verify continuous control behavior across mode transitions.}
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% Strategy
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Reachability analysis verifies that continuous control modes satisfy discrete
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transition requirements.
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% Outcome
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Engineers design continuous controllers using standard practices while
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maintaining formal correctness guarantees. Mode transitions provably occur safely and at
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the correct times.
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% OUTCOME 3 Title
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\item \textit{Demonstrate autonomous reactor startup control with safety
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guarantees.}
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% Strategy
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A small modular reactor simulation using industry-standard control hardware
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implements this methodology.
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% Outcome
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Control engineers implement high-assurance autonomous controls on
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industrial platforms they already use, enabling autonomy without retraining
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costs or new equipment development.
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\end{enumerate}
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