5050b9e71e
Scram PJ reach from the bounding-box union of: - hot-standby box (mode_boundaries.q_shutdown) - heatup-tight reach envelope (results/reach_heatup_pj_tight.mat) - operation-LQR reach envelope (results/reach_operation_result.mat) - LOCA operation envelope (results/reach_loca_operation.mat, 3s) with precursor + temperature outliers clamped to physical bounds. Results at probe horizons: T=10s: 10890 sets in 480s wall — n ∈ [-8e-4, 0.047] T_c [231, 362] T=30s: 16925 sets in 2892s wall — n ∈ [-4e-4, 0.021] T_c [229, 361] T=60s: 23919 sets in 705s wall — n ∈ [-2e-4, 0.009] T_c [226, 359] Monotone n decay, factor-of-5-per-minute even from the wide union. This is the defensible scram-obligation version: starts from anywhere the plant could plausibly be (including LOCA-perturbed operation state), proves n decays. X_exit(scram)=n≤1e-4 still not reached in 60s — same T_max-vs-plant-decay mismatch previously flagged. Fixed: missing Printf import that had failed the summary block on the first run (results still computed correctly, just the final print errored; the matwrite is after the print so the mat file wasn't saved on that run). Journal entry for 2026-04-21 extended with the fat-entry result + the LOCA-reach 3s-horizon numerical-looseness apass. 38 pages. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Lab Journal
___
,' `.
/ ___ \ n, C_i,
| ( UO2 ) | T_f, T_c, T_cold
\ ‾‾‾ / |
`.___,' v
||||| →→→→ [ controller ] →→→→ rods
|||||
‾‾‾‾‾‾‾‾‾‾‾‾‾ primary loop
___________
| SG | Q_sg(t) ∈ [Q_min, Q_max]
|____________|
The HAHACS invention log for the pwr-hybrid-3-demo preliminary
example. Each dated session gets an entry. The goal: a reader in 2030
should be able to rebuild the thesis work from this journal alone.
Structure
journal/
preamble.tex shared LaTeX setup (fonts, listings, callouts, macros)
journal.tex top-level aggregator (builds all entries into one PDF)
entries/ dated session entries, one file per session
YYYY-MM-DD-{topic-slug}.tex
figures/ journal-specific figures (referenced from entries)
README.md this file
Conventions
Filename
entries/YYYY-MM-DD-{topic-slug}.tex. One file per session. If a day has multiple distinct sessions, use time-of-day in the slug (e.g., 2026-04-20-morning-predicates.tex and 2026-04-20-evening-mega-session.tex).
Entry skeleton
\session{2026-04-17}{duration}{one-line summary}
\section{Session: ... (YYYY-MM-DD)}
\label{sec:YYYYMMDD}
\subsection*{Goal}
What I set out to do and why.
\subsection*{What landed}
...
\subsection*{Key decisions}
...
\subsection*{Dead ends}
...
\subsection*{Derivations}
...
\subsection*{Results}
...
\subsection*{Limitations recorded}
...
\subsection*{Open at close}
...
Entries compile standalone (each starts with \input{../preamble.tex} wrapped in a conditional so it only pulls preamble when not already loaded by journal.tex), or together via journal.tex.
Two entry styles
- A-style (deep / invention-log): full derivations, code commentary, dead-ends, embedded figures, terminal output where useful. Used for retroactive entries and sessions that land meaningful artifacts.
- B-style (narrative + pointers): end-of-session notes. Uses
\apass{...}callouts to flag spots that need a later A-pass.
Callout boxes
From preamble.tex:
| Environment | Use |
|---|---|
derivation |
Math derivations |
decision |
Design choices with rationale + alternatives |
deadend |
Paths that didn't work |
limitation |
Soundness gaps, known-approximate behavior |
Plus the inline \apass{text} marker for A-pass TODOs.
Code inclusion
\juliafile[options]{path/to/file.jl}— includes a Julia source file as a numbered listing.\matlabfile[...]{...}— for MATLAB sources.- Or inline with
lstlistingenvironment andlanguage=Juliafor snippets.
Always include the path as the listing caption so readers can find the file.
Figures
Figures live in ../docs/figures/ (shared with the thesis) or figures/ (journal-only). The preamble sets \graphicspath to check both.
Always include:
- A descriptive caption (what's on axes, what's being shown).
- A discussion in the surrounding prose — what the figure proves or illustrates. Figures without discussion are noise.
Terminal output
For a numerical result or an error that drove a decision, include the actual terminal text in a lstlisting block with style=terminal:
\begin{lstlisting}[style=terminal]
TMJets: 10583 reach-sets
T_c envelope: [274.45, 295.0] C
FAILED: AssertionError: radius must be nonnegative
\end{lstlisting}
Don't include full logs — only the lines that changed what you did next.
Build
cd journal
latexmk -pdf journal.tex # whole journal as one PDF
latexmk -pdf entries/2026-04-17-controllers-linear-reach.tex # one entry
Requires TeX Live with tcolorbox, listings, inconsolata, siunitx, cleveref, hyperref, fancyhdr. All in the standard distribution.
Not a replacement for
claude_memory/— short AI-context notes, Markdown, different audience.reachability/WALKTHROUGH.md— standalone doc summarizing current state of reach analysis.- Git commit messages — per-commit rationale for code changes.
The journal is the chronological narrative of the work. The others are snapshots, summaries, or pointers. They're all legitimate; they do different things.