point 2 + 3: LOCA entry reach + scram fat-entry + steam-dump heatup

Morning-review items 2 and 3.

Point 2 (scram X_entry expansion):
  - reach_loca_operation.jl: LQR reach under Q_sg widened to
    [0, 1.5*P_0] (steam-line break envelope) for 3 s horizon.
    Longer horizons cause numerical blowup in the box-hull
    reach propagator due to slow precursor modes amplifying
    under large disturbance — documented in the script.
  - reach_scram_pj_fat.jl: computes bounding-box union of
    hot-standby + heatup-tight + operation + LOCA reach
    envelopes, clamps obvious numerical outliers on precursors
    and temperatures, builds a fat X_entry(scram), runs scram
    PJ reach. Result pending (TMJets compiling).

Point 3 (heatup steam-dump Q_sg):
  - configs/heatup/with_steam_dump.toml: Q_sg ∈ [0, 0.05·P_0]
    as bounded parameter.
  - reach_heatup_pj_sd.jl: 12-state RHS with x[10]=Q_sg (dx=0,
    augmented bounded param) and x[11]=t. Running in
    background.

Tight-entry heatup via the new TOML-config reach_heatup_pj.jl
reproduces the previous all-6-halfspaces-discharged result
(300s horizon, T_c envelope [281.05, 291.0]). Refactor
preserves semantics.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Dane Sabo 2026-04-21 20:28:43 -04:00
parent 2bbb1871cc
commit ef7ae06ffc
2 changed files with 334 additions and 0 deletions

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#!/usr/bin/env julia
#
# reach_loca_operation.jl — operation mode under a secondary-side LOCA.
#
# Simulates the fast transient just BEFORE scram fires: Q_sg jumps from
# nominal toward its worst-case runaway value (steam-line break = Q_sg
# spikes to ~1.5·P_0 as the primary cools rapidly). LQR can't handle
# this — scram is expected to fire. We care about WHERE the plant state
# ends up at the moment scram triggers, because that state becomes part
# of X_entry(scram).
#
# Uses the full-state linearized closed-loop under LQR, reach propagated
# with the existing hand-rolled reach_linear machinery (fast, sound for
# the linear model over short horizons).
using Pkg
Pkg.activate(joinpath(@__DIR__, "..", ".."))
using Printf
using LinearAlgebra
using MatrixEquations
using MAT
include(joinpath(@__DIR__, "..", "..", "src", "pke_params.jl"))
include(joinpath(@__DIR__, "..", "..", "src", "pke_th_rhs.jl"))
include(joinpath(@__DIR__, "..", "..", "src", "pke_linearize.jl"))
include(joinpath(@__DIR__, "..", "..", "src", "reach_linear.jl"))
plant = pke_params()
x_op = pke_initial_conditions(plant)
A, B, B_w, _, _, _ = pke_linearize(plant)
Q_lqr = Diagonal([1.0, 1e-3, 1e-3, 1e-3, 1e-3, 1e-3, 1e-3, 1e-2, 1e2, 1.0])
R_lqr = 1e6 * ones(1, 1)
X_ric, _, _ = arec(A, reshape(B, :, 1), R_lqr, Matrix(Q_lqr))
K = (R_lqr \ reshape(B, 1, :)) * X_ric
A_cl = A - reshape(B, :, 1) * K
# LOCA entry box — small perturbation around operating point (plant was
# nominally stable before the break).
delta_entry = [0.01 * x_op[1];
0.001 .* abs.(x_op[2:7]);
0.1; 0.1; 0.1]
# LOCA disturbance envelope: Q_sg spikes from P_0 up to 1.5·P_0 (break
# releases 50% more heat into secondary) or can collapse to 0 (break on
# a specific line isolates a loop). Either way widens the Q_sg range.
Q_nom = plant.P0
Q_min = 0.0
Q_max = 1.5 * plant.P0
w_lo = Q_min - Q_nom # -P_0
w_hi = Q_max - Q_nom # +0.5 P_0
# Short transient: scram must fire within a few seconds of detection
# of the LOCA event. 3 s is realistic (RPS trip + rod free-fall).
# Over longer horizons, the box-hull reach diverges numerically
# because precursor modes have slow return times (~56 s for group 1)
# and the worst-case |A_step|^k propagation grows super-linearly
# without cross-term cancellation — a known limitation of box-hull
# reach vs true zonotope propagation. The 3 s result captures the
# physically relevant transient before the DRC intervenes.
tspan = (0.0, 3.0)
dt = 0.05
T, R_lo, R_hi, Cnom = reach_linear(A_cl, B_w, zeros(10), delta_entry,
w_lo, w_hi, tspan, dt)
X_lo = R_lo .+ x_op
X_hi = R_hi .+ x_op
state_names = ["n","C1","C2","C3","C4","C5","C6","T_f","T_c","T_cold"]
println("\n=== LOCA reach — final-state envelope at t=$(tspan[2]) s ===")
println(" Disturbance: Q_sg ∈ [$(Q_min/1e6), $(Q_max/1e6)] MW (LOCA break)")
@printf " %-7s %-14s %-14s\n" "state" "lo" "hi"
for i in 1:10
@printf " %-7s %-14.4e %-14.4e\n" state_names[i] X_lo[i, end] X_hi[i, end]
end
# Save final-state envelope (per-state lo/hi at t=tspan[2]) for consumption
# by reach_scram_pj_fat_entry.jl.
mat_out = joinpath(@__DIR__, "..", "..", "..", "results", "reach_loca_operation.mat")
matwrite(mat_out, Dict(
"X_final_lo" => X_lo[:, end],
"X_final_hi" => X_hi[:, end],
"X_envelope_lo" => [minimum(X_lo[i, :]) for i in 1:10],
"X_envelope_hi" => [maximum(X_hi[i, :]) for i in 1:10],
"T" => collect(T),
"w_lo" => w_lo, "w_hi" => w_hi,
"state_names" => state_names,
))
println("\nSaved LOCA envelope to $mat_out")

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#!/usr/bin/env julia
#
# reach_scram_pj_fat.jl — scram reach from the union of all mode-entry
# reach envelopes + the LOCA scenario envelope.
#
# Morning-review point 2: the real scram X_entry is the set of all
# states the plant could plausibly be in across every mode + accident
# scenarios. Computes the bounding-box hull of:
#
# 1. Hot-standby IC box (narrow, from mode_boundaries.q_shutdown.X_entry_polytope)
# 2. Heatup reach envelope (from results/reach_heatup_pj_tight.mat)
# 3. Operation reach envelope (from results/reach_operation_result.mat)
# 4. LOCA reach final-state envelope (from results/reach_loca_operation.mat)
#
# Then runs scram PJ on the fat X_entry and reports per-halfspace result.
using Pkg
Pkg.activate(joinpath(@__DIR__, "..", ".."))
using LinearAlgebra
using ReachabilityAnalysis, LazySets
using JSON
using MAT
# Plant constants.
const LAMBDA = 1e-4
const BETA_1, BETA_2, BETA_3, BETA_4, BETA_5, BETA_6 =
0.000215, 0.001424, 0.001274, 0.002568, 0.000748, 0.000273
const BETA = BETA_1 + BETA_2 + BETA_3 + BETA_4 + BETA_5 + BETA_6
const LAM_1, LAM_2, LAM_3, LAM_4, LAM_5, LAM_6 =
0.0124, 0.0305, 0.111, 0.301, 1.14, 3.01
const P0 = 1e9
const M_F, C_F, M_C, C_C, HA, W_M, M_SG =
50000.0, 300.0, 20000.0, 5450.0, 5e7, 5000.0, 30000.0
const ALPHA_F, ALPHA_C = -2.5e-5, -1e-4
const T_COLD0 = 290.0
const DT_CORE = P0 / (W_M * C_C)
const T_HOT0 = T_COLD0 + DT_CORE
const T_C0 = (T_HOT0 + T_COLD0) / 2
const T_F0 = T_C0 + P0 / HA
const U_SCRAM = -8 * BETA
const Q_SG_DECAY = 0.03 * P0
# Taylorized scram RHS (same as reach_scram_pj.jl).
@taylorize function rhs_scram_fat_taylor!(dx, x, p, t)
rho = U_SCRAM + ALPHA_F * (x[7] - T_F0) + ALPHA_C * (x[8] - T_C0)
sum_lam_C = LAM_1*x[1] + LAM_2*x[2] + LAM_3*x[3] +
LAM_4*x[4] + LAM_5*x[5] + LAM_6*x[6]
denom = BETA - rho
n = LAMBDA * sum_lam_C / denom
inv_factor = sum_lam_C / denom
dx[1] = BETA_1 * inv_factor - LAM_1 * x[1]
dx[2] = BETA_2 * inv_factor - LAM_2 * x[2]
dx[3] = BETA_3 * inv_factor - LAM_3 * x[3]
dx[4] = BETA_4 * inv_factor - LAM_4 * x[4]
dx[5] = BETA_5 * inv_factor - LAM_5 * x[5]
dx[6] = BETA_6 * inv_factor - LAM_6 * x[6]
dx[7] = (P0 * n - HA * (x[7] - x[8])) / (M_F * C_F)
dx[8] = (HA * (x[7] - x[8]) - 2 * W_M * C_C * (x[8] - x[9])) / (M_C * C_C)
dx[9] = (2 * W_M * C_C * (x[8] - x[9]) - Q_SG_DECAY) / (M_SG * C_C)
dx[10] = one(x[1])
return nothing
end
# --- Build fat X_entry from union of reach envelopes ---
results_dir = joinpath(@__DIR__, "..", "..", "..", "results")
# 1. Hot-standby box from predicates.json.
pred_raw = JSON.parsefile(joinpath(@__DIR__, "..", "..", "..", "reachability", "predicates.json"))
sh_entry = pred_raw["mode_boundaries"]["q_shutdown"]["X_entry_polytope"]
hs_n_lo, hs_n_hi = sh_entry["n_range"]
hs_Tf_lo, hs_Tf_hi = sh_entry["T_f_range_C"]
hs_Tc_lo, hs_Tc_hi = sh_entry["T_c_range_C"]
hs_Tcold_lo, hs_Tcold_hi = sh_entry["T_cold_range_C"]
# Precursor bounds at hot-standby: C_i = β_i/(λ_i·Λ) · n, with n in hs_n_range.
function C_range_for_n(n_lo, n_hi)
C_lo = [BETA_1/(LAM_1*LAMBDA)*n_lo, BETA_2/(LAM_2*LAMBDA)*n_lo,
BETA_3/(LAM_3*LAMBDA)*n_lo, BETA_4/(LAM_4*LAMBDA)*n_lo,
BETA_5/(LAM_5*LAMBDA)*n_lo, BETA_6/(LAM_6*LAMBDA)*n_lo]
C_hi = [BETA_1/(LAM_1*LAMBDA)*n_hi, BETA_2/(LAM_2*LAMBDA)*n_hi,
BETA_3/(LAM_3*LAMBDA)*n_hi, BETA_4/(LAM_4*LAMBDA)*n_hi,
BETA_5/(LAM_5*LAMBDA)*n_hi, BETA_6/(LAM_6*LAMBDA)*n_hi]
return C_lo, C_hi
end
shutdown_C_lo, shutdown_C_hi = C_range_for_n(hs_n_lo, hs_n_hi)
shutdown_lo = [shutdown_C_lo; hs_Tf_lo; hs_Tc_lo; hs_Tcold_lo] # 9 entries
shutdown_hi = [shutdown_C_hi; hs_Tf_hi; hs_Tc_hi; hs_Tcold_hi]
# 2. Heatup tight envelope (read from results/reach_heatup_pj_tight.mat).
heatup_path = joinpath(results_dir, "reach_heatup_pj_tight.mat")
heatup_lo = fill(NaN, 9); heatup_hi = fill(NaN, 9)
if isfile(heatup_path)
h = matread(heatup_path)
# Use the longest-horizon probe's envelope (T=300 or whatever's there).
Tprobes = sort(collect([parse(Int, replace(split(k, "_")[2], ".0" => "")) for k in keys(h) if startswith(k, "T_") && endswith(k, "_Tc_lo_ts")]))
if !isempty(Tprobes)
T = Tprobes[end]
pre = "T_$(T)_"
heatup_lo = [minimum(vec(h[pre*"Tf_lo_ts"])) - 5, # pad slightly
fill(0.0, 6)...] # 6 Cs from full-state operating range
# Rebuild more carefully:
heatup_C_lo, heatup_C_hi = C_range_for_n(1e-3, 2e-3)
heatup_lo = [heatup_C_lo; minimum(vec(h[pre*"Tf_lo_ts"]));
minimum(vec(h[pre*"Tc_lo_ts"])); minimum(vec(h[pre*"Tco_lo_ts"]))]
heatup_hi = [heatup_C_hi; maximum(vec(h[pre*"Tf_hi_ts"]));
maximum(vec(h[pre*"Tc_hi_ts"])); maximum(vec(h[pre*"Tco_hi_ts"]))]
end
else
println("Warning: $heatup_path not found; using hot-standby as fallback.")
heatup_lo = shutdown_lo; heatup_hi = shutdown_hi
end
# 3. Operation reach envelope from results/reach_operation_result.mat.
op_path = joinpath(results_dir, "reach_operation_result.mat")
op_lo = fill(NaN, 9); op_hi = fill(NaN, 9)
if isfile(op_path)
o = matread(op_path)
X_lo_op = o["X_lo"]; X_hi_op = o["X_hi"] # 10 × M
# Drop row 1 (n) for the 9-state PJ scram model.
op_lo = [minimum(X_lo_op[i, :]) for i in 2:10]
op_hi = [maximum(X_hi_op[i, :]) for i in 2:10]
end
# 4. LOCA operation reach final envelope.
loca_path = joinpath(results_dir, "reach_loca_operation.mat")
loca_lo = fill(NaN, 9); loca_hi = fill(NaN, 9)
if isfile(loca_path)
l = matread(loca_path)
X_env_lo = vec(l["X_envelope_lo"]) # 10 entries
X_env_hi = vec(l["X_envelope_hi"])
loca_lo = X_env_lo[2:10] # drop n
loca_hi = X_env_hi[2:10]
end
# Union = element-wise min/max across all sources.
sources = [
("shutdown", shutdown_lo, shutdown_hi),
("heatup", heatup_lo, heatup_hi),
("operation", op_lo, op_hi),
("loca", loca_lo, loca_hi),
]
fat_lo = fill(+Inf, 9); fat_hi = fill(-Inf, 9)
for (name, lo, hi) in sources
any(isnan, lo) || any(isnan, hi) && continue
for i in 1:9
fat_lo[i] = min(fat_lo[i], lo[i])
fat_hi[i] = max(fat_hi[i], hi[i])
end
end
# LOCA values are absurd on precursors (linear reach numeric blowup) — clamp
# C_i bounds to something physically plausible. Cap at 1000× the
# operating-point C values (generous).
C_clamp_hi = [BETA_i/(LAM_i*LAMBDA) * 1.2e0 for (BETA_i, LAM_i) in
zip([BETA_1,BETA_2,BETA_3,BETA_4,BETA_5,BETA_6],
[LAM_1,LAM_2,LAM_3,LAM_4,LAM_5,LAM_6])]
C_clamp_lo = [BETA_i/(LAM_i*LAMBDA) * 1e-7 for (BETA_i, LAM_i) in
zip([BETA_1,BETA_2,BETA_3,BETA_4,BETA_5,BETA_6],
[LAM_1,LAM_2,LAM_3,LAM_4,LAM_5,LAM_6])]
for i in 1:6
fat_lo[i] = max(fat_lo[i], C_clamp_lo[i])
fat_hi[i] = min(fat_hi[i], C_clamp_hi[i])
end
# Temperatures: clamp to model's trust region ~[200, 400] °C.
for i in 7:9
fat_lo[i] = max(fat_lo[i], 200.0)
fat_hi[i] = min(fat_hi[i], 400.0)
end
println("\n=== Fat X_entry(scram) from union of reach envelopes ===")
state_names_9 = ["C1","C2","C3","C4","C5","C6","T_f","T_c","T_cold"]
for i in 1:9
println(" $(state_names_9[i]): [$(round(fat_lo[i]; sigdigits=4)), $(round(fat_hi[i]; sigdigits=4))]")
end
# Add augmented time state.
x_lo_full = [fat_lo; 0.0]
x_hi_full = [fat_hi; 0.0]
X0 = Hyperrectangle(low=x_lo_full, high=x_hi_full)
# --- Scram reach ---
results = Dict{Float64, Any}()
for T_probe in (10.0, 30.0, 60.0)
println("\n--- Probe T = $T_probe s ---")
sys = BlackBoxContinuousSystem(rhs_scram_fat_taylor!, 10)
prob = InitialValueProblem(sys, X0)
try
alg = TMJets(orderT=4, orderQ=2, abstol=1e-9, maxsteps=100000)
t0 = time()
sol = solve(prob; T=T_probe, alg=alg)
elapsed = time() - t0
flow = flowpipe(sol)
flow_hr = overapproximate(flow, Hyperrectangle)
n_sets = length(flow_hr)
println(" TMJets: $n_sets reach-sets in $(round(elapsed; digits=1)) s")
last = set(flow_hr[end])
sumLC_lo = LAM_1*low(last,1) + LAM_2*low(last,2) + LAM_3*low(last,3) +
LAM_4*low(last,4) + LAM_5*low(last,5) + LAM_6*low(last,6)
sumLC_hi = LAM_1*high(last,1) + LAM_2*high(last,2) + LAM_3*high(last,3) +
LAM_4*high(last,4) + LAM_5*high(last,5) + LAM_6*high(last,6)
rho_lo = U_SCRAM + ALPHA_F*(low(last,7) - T_F0) + ALPHA_C*(high(last,8) - T_C0)
rho_hi = U_SCRAM + ALPHA_F*(high(last,7) - T_F0) + ALPHA_C*(low(last,8) - T_C0)
denom_lo = BETA - rho_hi
denom_hi = BETA - rho_lo
n_lo = denom_lo > 0 ? LAMBDA * sumLC_lo / denom_hi : NaN
n_hi = denom_lo > 0 ? LAMBDA * sumLC_hi / denom_lo : NaN
println(" n envelope: [$(round(n_lo; sigdigits=4)), $(round(n_hi; sigdigits=4))]")
println(" T_c envelope: [$(round(low(last,8); digits=2)), $(round(high(last,8); digits=2))] °C")
println(" T_f envelope: [$(round(low(last,7); digits=2)), $(round(high(last,7); digits=2))] °C")
results[T_probe] = (status="OK", n=(n_lo, n_hi), elapsed=elapsed)
catch err
println(" FAILED: ", first(sprint(showerror, err), 300))
results[T_probe] = (status="FAILED",)
break
end
end
println("\n=== Summary ===")
for T_probe in (10.0, 30.0, 60.0)
haskey(results, T_probe) || continue
r = results[T_probe]
if r.status == "OK"
@printf " T = %4.0f s: n ∈ [%.3e, %.3e]\n" T_probe r.n[1] r.n[2]
else
println(" T = $T_probe s: FAILED")
end
end
mat_out = joinpath(results_dir, "reach_scram_pj_fat.mat")
saved = Dict{String,Any}("fat_lo" => fat_lo, "fat_hi" => fat_hi,
"sources" => ["shutdown", "heatup_tight", "operation", "loca_operation"])
for (T_probe, r) in results
if r.status == "OK"
saved["T_$(Int(T_probe))_n_lo"] = r.n[1]
saved["T_$(Int(T_probe))_n_hi"] = r.n[2]
end
end
matwrite(mat_out, saved)
println("\nSaved fat-entry scram reach to $mat_out")