predicates.json is the single source of truth for concretizing the
FRET-spec predicates (t_avg_above_min, t_avg_in_range, p_above_crit,
inv1_holds, inv2_holds) as polytopes {x : A x <= b}. Until now these
were abstract booleans in the synthesis spec; reach analysis
re-invented ad-hoc thresholds that weren't tied to the spec. Closes
the Thrust-1-meets-Thrust-3 seam.
T_standby now defined as T_c0 - 60 F = 275 C (from user review).
Replaces the earlier simplification where shutdown IC held all temps
at T_cold0. 275 C is inside the model's +/-50 C trust region around
operating point and above coolant saturation at reduced pressure.
load_predicates.m in MATLAB reads the JSON and resolves rhs_expr
strings (which reference plant-derived constants like T_c0, T_cold0,
T_standby) into numeric bounds. Returns per-predicate (A_poly, b_poly)
plus a constants struct.
main_mode_sweep.m now pulls T_standby from predicates and uses it
for shutdown + heatup ICs. Heatup horizon extended to 90 min to
cover the wider 60 F -> operating range at 28 C/hr tech-spec limit.
reach_operation.m reads delta_safe_Tc from the t_avg_in_range
halfspace instead of hardcoding +/-5 K. Current concretization is
+/-2.78 C (~5 F); LQR reach still shows 28x margin.
inv1_holds and inv2_holds are marked PLACEHOLDER in the JSON —
engineering best guesses, not derived from a specific plant's tech
specs or a DNBR correlation. Revisit before thesis defense.
Hacker-Split: single-source concretization for FRET predicates,
end seam with reach.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Fill out the DRC mode set with ctrl_shutdown (u = -5*beta), ctrl_scram
(u = -8*beta), and ctrl_heatup (feedback-linearizing P on ramped T_avg
reference, saturated u, no integrator). Add ctrl_operation_lqr as a
full-state-feedback counterpart to ctrl_operation — K cached, closed-loop
essentially perfect under the 100%->80% Q_sg step where plain P has ~5F
overshoot.
Add pke_linearize for numerical (A, B, B_w) Jacobians at any operating
point; test_linearize confirms ~4e-4 rel err vs nonlinear sim for a
5% Q_sg step. Extend pke_solver with an optional x0 argument so each
mode can start from a plausible IC.
main_mode_sweep.m exercises all five modes back-to-back and saves the
4-panel plots. CLAUDE.md updated with model-validity-range note (trust
region is ~+/-50C around operating point; true cold shutdown is out of
scope for the linear feedback coefficients).
Hacker-Split: build out control layer end-to-end for reachability.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
