244a744e67
Following user's review feedback (point 1): prompt_critical_margin_heatup: a new entry under safety_limits that proves the PJ reduction's validity condition (beta - rho > 0 with margin) rather than hand-waving it. Controller-specific specialization for heatup: under feedback linearization, rho_total = Kp*(T_ref - T_c), so rho ≤ 0.5*beta iff T_c ≥ T_ref - 32.5. Worst-case T_ref = T_c0 at ramp end, so T_c ≥ 275.85 is sufficient, which our tight-entry reach clears trivially. Conjoined into inv1_holds. Safety proofs now target BOTH the physical bounds AND the conditions that make the PJ approximation sound. Saves Dane's rigor-over-vibes instinct (saved to memory). plot_reach_tubes.jl: four-panel visualization of a reach-result .mat: (1) T_c / T_hot / T_cold envelopes overlaid (2) ΔT_core = T_hot - T_cold (power proxy, right-axis MW) (3) rho envelope in dollars, with ±1$ prompt lines (4) n envelope Operation-mode plot saved to docs/figures/reach_operation_tubes.png. Heatup PJ version pending — needs full per-step data from the running reach_heatup_pj_tight_full.jl. reach_heatup_pj.jl + reach_heatup_pj_tight_full.jl now save per-timestep envelopes (t_arr, Tc_lo_ts, Tc_hi_ts, ...) so the plotting script can overlay tubes vs time. Next up: polytopic / SOS barriers, Tikhonov error bound for PJ. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
code
Plant model, controllers, and reach-analysis toolchain for the HAHACS preliminary example. All Julia.
What this is
A 10-state coupled neutronics + thermal-hydraulics model (point kinetic equations + lumped thermal loop) with continuous-mode controllers for each of the DRC modes (shutdown, heatup, operation, scram), plus a hand-rolled linear reach-tube propagator, a Lyapunov-ellipsoid barrier attempt, and scaffolding for TMJets-based nonlinear reach.
Ported from MATLAB on 2026-04-20 once the reach experiments made it
clear that Julia's stack (OrdinaryDiffEq, MatrixEquations,
ReachabilityAnalysis, LazySets, @taylorize) was the right tool
for everything we need going forward. The MATLAB originals are in
the git history.
Running
First time:
cd code
julia --project=. -e 'using Pkg; Pkg.instantiate()'
Subsequent:
julia --project=. scripts/main_mode_sweep.jl # all 5 DRC modes, figures
julia --project=. scripts/reach_operation.jl # operation-mode linear reach
julia --project=. scripts/barrier_lyapunov.jl # Lyapunov barrier attempt
julia --project=. scripts/barrier_compare_OL_CL.jl # OL vs CL barrier
julia --project=. scripts/reach_heatup_nonlinear.jl # nonlinear heatup (10s cap)
Figures save to ../docs/figures/. Reach results save to
../reachability/*.mat (gitignored).
Structure
See CLAUDE.md for the architectural overview and ../journal/ for
the invention-log-style narrative of how this code got written.
Dependencies
From Project.toml:
OrdinaryDiffEq— ODE solver, Rodas5 for stiff systems.MatrixEquations—arecfor LQR Riccati,lyapcfor Lyapunov.ReachabilityAnalysis+LazySets— reach sets and set operations.Plots— figures (GR backend by default).JSON— read../reachability/predicates.json.MAT— save results.
Manifest.toml is gitignored; regenerate locally on first
Pkg.instantiate().