Earlier placeholder claimed ramp-rate limits weren't expressible as
state halfspaces without augmentation. That was wrong: dT_c/dt is
linear in (T_f, T_c, T_cold) directly from pke_th_rhs (no neutronics
coupling), so |dT_c/dt| <= r_max is two clean halfspaces over x.
Coefficients from pke_params:
a_f = hA / (M_c*c_c) = +0.4587 /s
a_c = -(hA + 2*W*c_c)/(M_c*c_c) = -0.9587 /s
a_cold = 2*W*c_c / (M_c*c_c) = +0.5000 /s
Sum = 0 exact (equilibrium when all T's equal).
Limit chosen: +/- 50 C/hr (tech-spec 28 C/hr + transient overshoot
budget). Verified on actual heatup sim: max dT_c/dt = 48.5 C/hr, min
= 0 C/hr. Passes our placeholder but tight — a strict 28 C/hr tech-
spec invariant would be violated by current ctrl_heatup tuning
(overshoot factor ~1.7x during mid-ramp).
Generalized load_predicates.m to accept multi-coefficient halfspace
rows via "row": [[state_idx, coeff], ...] format, in addition to the
existing single-coefficient {state_index, coeff} form. Backward
compatible.
inv1_holds now conjoins fuel_centerline, cold_leg_subcooled, and the
two rate halfspaces. DNBR still not modeled (would need an
augmented predicate with a correlation-based safety margin).
Hacker-Split: Dane asked about heatup rate invariant; realizing
my earlier 'needs state augmentation' claim was wrong and the rate
constraint is already linear. Fix it, verify against actual sim.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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>
Three caveats surfaced during walkthrough lived only in the
conversation transcript before this commit. Now they live where
future agents and future-me will actually see them:
- reach_operation.m and reachability/README.md state prominently that
the current reach tube is an over-approximation of the LINEAR
model, not a sound tube for the nonlinear plant. Thesis-blocking
for a real safety claim. Upgrade paths documented.
- ctrl_heatup.m header and plant-model/CLAUDE.md note that the
feedback-linearization u_ff assumes exact alpha_f, alpha_c. Real
plants drift (burnup ~20%, boron ~10x, xenon). Robust treatment =
parametric reach with alpha as an interval.
- ctrl_heatup.m header and plant-model/CLAUDE.md note that sat() is
formally a 3-mode piecewise-affine sub-system. Operation-mode LQR
is dormant (trivially); heatup will need either a dormancy proof
or explicit hybrid modeling.
README.md top-level now has a run-commands table for the reach
artifacts and a pointer to the soundness status.
Hacker-Split: raise caveats from transcript to artifact so the work
is actually reviewable by people who weren't in the room.
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>
Folds three previously-separate pieces into one preliminary-example repo
for the HAHACS thesis:
- thesis/ (submodule) → gitea Thesis.git — the PhD proposal
- fret-pipeline/ — FRET requirements to AIGER controller (was
~/Documents/fret_processing/; prior single-commit history abandoned
per user decision)
- plant-model/ — 10-state PKE + lumped T/H PWR model (was
~/Documents/PKE_Playground/; never version-controlled before)
- presentations/2026DICE/ (submodule) → gitea 2026DICE.git
- reachability/, hardware/ — empty placeholders for Thrust 3 and HIL
- docs/architecture.md — how the discrete and continuous layers compose
- claude_memory/ — session notes and scratch knowledge pattern
Plant model refactored to thesis naming (x, plant, u, ref); pke_th_rhs
now takes u as an explicit arg instead of reading rho_ext from the
params struct. First two controllers built to the contract
u = ctrl_<mode>(t, x, plant, ref): ctrl_null (baseline) and
ctrl_operation (stabilizing, proportional on T_avg). Validated under a
100% -> 80% Q_sg step: ctrl_operation reduces steady-state T_avg drift
~47% vs. the unforced plant.
Root CLAUDE.md emphasizes that CLAUDE.md files are living documents and
that any knowledge not captured before a session ends is lost forever;
claude_memory/ holds the session-level notes that haven't stabilized
enough to graduate into a CLAUDE.md.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
