Scram reach via PJ model runs cleanly through all three probe
horizons:
T=10s: 6919 sets in 118s — n ∈ [0.0347, 0.0355]
T=30s: 9900 sets in 156s — n ∈ [0.0153, 0.0156]
T=60s: 12340 sets in 198s — n ∈ [0.00682, 0.00698]
Factor-of-two power decay per 30s matches the delayed-neutron group
structure (lambda_1=0.0124, half-life ~56s). At t=0 the algebraic n
drops from 1.0 → 0.15 (prompt jump captured as an instantaneous
algebraic adjustment); then tails off on precursor timescales.
Scram reach is completely sound across the full 60s horizon — no
step-budget truncation, unlike heatup beyond 300s.
HOWEVER: X_exit(scram) = n ≤ 1e-4 is not reached in 60s (current
n ~ 7e-3). This is a T_max vs plant-decay-rate mismatch, not a
control failure. Options documented in journal: redefine X_exit in
terms of shutdown margin (industry standard), extend T_max to 600s,
or loosen to n ≤ 0.05. Flagged for Dane's review.
Scram envelope summaries saved to reach_scram_pj_result.mat.
Journal now 33 pages, still compiles clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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