From 70608efdc85e96e4d0955f424a3a30b7877b59fa Mon Sep 17 00:00:00 2001
From: Codex Agent <codex@example.com>
Date: Sun, 23 Nov 2025 19:48:02 +0100
Subject: [PATCH] Show xenon/iodine inventories on dashboard

---
 src/reactor_sim/dashboard.py | 9 ++++-----
 tests/test_neutronics.py     | 9 +++++++++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/reactor_sim/dashboard.py b/src/reactor_sim/dashboard.py
index abfd4b9..2451d38 100644
--- a/src/reactor_sim/dashboard.py
+++ b/src/reactor_sim/dashboard.py
@@ -548,15 +548,14 @@ class ReactorDashboard:
         inventory = state.core.fission_product_inventory or {}
         particles = state.core.emitted_particles or {}
         lines: list[tuple[str, str]] = []
-        def fmt(symbol: str, label: str) -> tuple[str, str]:
-            qty = inventory.get(symbol, 0.0)
+        def fmt(symbol: str, label: str, qty: float) -> tuple[str, str]:
             threshold = constants.KEY_POISON_THRESHOLDS.get(symbol)
             flag = " !" if threshold is not None and qty >= threshold else ""
             return (f"{label}{flag}", f"{qty:9.2e}")
 
-        lines.append(fmt("Xe", "Xe (xenon)"))
-        lines.append(fmt("Sm", "Sm (samarium)"))
-        lines.append(fmt("I", "I (iodine)"))
+        lines.append(fmt("Xe", "Xe (xenon)", getattr(state.core, "xenon_inventory", 0.0)))
+        lines.append(fmt("Sm", "Sm (samarium)", inventory.get("Sm", 0.0)))
+        lines.append(fmt("I", "I (iodine)", getattr(state.core, "iodine_inventory", 0.0)))
         lines.append(("Neutrons (src)", f"{particles.get('n', 0.0):9.2e}"))
         lines.append(("Gammas", f"{particles.get('gamma', 0.0):9.2e}"))
         lines.append(("Alphas", f"{particles.get('alpha', 0.0):9.2e}"))
diff --git a/tests/test_neutronics.py b/tests/test_neutronics.py
index ca4d994..298a762 100644
--- a/tests/test_neutronics.py
+++ b/tests/test_neutronics.py
@@ -23,3 +23,12 @@ def test_reactivity_increases_with_rod_withdrawal():
     rho_full_out = dynamics.reactivity(state, control_fraction=0.0)
     rho_half = dynamics.reactivity(state, control_fraction=0.5)
     assert rho_full_out > rho_half
+
+
+def test_poisons_accumulate_under_power():
+    dynamics = NeutronDynamics()
+    state = _core_state(power=800.0, flux=1e6)
+    dynamics.update_poisons(state, dt=100.0)
+    dynamics.update_poisons(state, dt=100.0)
+    assert state.iodine_inventory > 0.0
+    assert state.xenon_inventory > 0.0