RIA Fast Shutdown Simulator (v0.7)

Author: Steven Lanier-Egu • Credit: SEAL Division

This repository pairs a Typora-ready paper and a runnable Python simulator that validates a fast, orchestrated shutdown for reactivity-initiated accidents (RIA) in high-burnup fuel:

• Sense → Release → Terminate → Recover control story
• Worth-vs-time targets (primary): ≥ 0.5 mk @ 20 ms, ≥ 1.0 mk @ 50 ms
• Non-blocking invariant: supervisory delay ≤ 500 µs
• Artifacts: CSV, JSON log, reactivity & power plots
• Zenodo record (paper + software): https://doi.org/10.5281/zenodo.17868291

Contents

• ria_sim_v07.py — reference simulator with checks and artifact generation
• docs/RIA_Protection_Upgrade_Stack_v0.7.md — paper (with Appendix A: Simulation Methods & Validation)
• .github/workflows/ci.yml — smoke-test CI
• pyproject.toml, requirements.txt, Makefile — packaging and quick demo

Quickstart

python3 -m venv .venv && source .venv/bin/activate
python -m pip install -r requirements.txt

# Run default rod-ejection scenario
python ria_sim_v07.py --outdir ./out

# Alternative: cold-water insertion
python ria_sim_v07.py --scenario cold_water --outdir ./out_cwi

CLI Options

# show help
python ria_sim_v07.py -h

# knobs for experiments / CI sweeps
python ria_sim_v07.py --outdir ./out \
  --scenario rod_ejection \
  --primary-fail-prob 0.0 \
  --non-blocking-us 400 \
  --seed 1

Outputs

• out/timeseries.csv — time, ρ, normalized power, primary/backup/poison worths, event timestamps
• out/sim_log.json — config, events, and pass/fail for each acceptance check
• out/reactivity.png, out/power.png — one figure per plot with event markers (trip / primary / backup / poison)

What the Simulator Verifies

• Worth-vs-time envelopes (relative to trip): primary ≥0.5 mk @ +20 ms and ≥1.0 mk @ +50 ms; backup path checked when it fires
• Non-blocking invariant: supervisory delay capped at 500 µs
• Tail termination: poison/spectrum path engages from ≥10 ms toward the 1 s margin goal
• Artifacts: all runs emit CSV/JSON/plots for auditability

Paper

• See docs/RIA_Protection_Upgrade_Stack_v0.7.md (includes a one-page executive overview and Appendix A — Simulation Methods & Validation).

CI

GitHub Actions (on push/PR) installs deps, runs the simulator, and asserts that the checks pass.

Packaging & Make

• Editable install: pip install -e . (uses pyproject.toml)
• Quick demo: make demo (creates venv, installs, runs ria-sim entrypoint)

Citation

If you use this work, please cite the Zenodo record:

Lanier-Egu, S. (2025). RIA Protection Upgrade Stack v0.7 — Simulation-Validated Fast Shutdown Orchestration for High-Burnup Reactors. Zenodo. https://doi.org/10.5281/zenodo.17868291

@software{lanier-egu_ria_v07_2025,
  author    = {Steven Lanier-Egu},
  title     = {RIA Protection Upgrade Stack v0.7 — Simulation-Validated Fast Shutdown Orchestration for High-Burnup Reactors},
  year      = {2025},
  doi       = {10.5281/zenodo.17868291},
  url       = {https://doi.org/10.5281/zenodo.17868291},
  version   = {v0.7}
}

License

MIT (see LICENSE). Documentation included under the same repository unless otherwise noted.

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Reactivity units: mk denotes milli-k (Δk/k × 1e-3). One dollar equals β_eff of the core (plant-specific).