Improve reactor controls, reactions, and maintenance UI

src/reactor_sim/constants.py

@@ -10,10 +10,16 @@ COOLANT_HEAT_CAPACITY = 4_200.0  # J/(kg*K) for water/steam
 COOLANT_DENSITY = 700.0  # kg/m^3 averaged between phases
 MAX_CORE_TEMPERATURE = 1_800.0  # K
 MAX_PRESSURE = 15.0  # MPa typical PWR primary loop limit
-CONTROL_ROD_SPEED = 0.05  # fraction insertion per second
+CONTROL_ROD_SPEED = 0.03  # fraction insertion per second
 STEAM_TURBINE_EFFICIENCY = 0.34
 GENERATOR_EFFICIENCY = 0.96
 ENVIRONMENT_TEMPERATURE = 295.0  # K
 AMU_TO_KG = 1.660_539_066_60e-27
 MEV_TO_J = 1.602_176_634e-13
 ELECTRON_FISSION_CROSS_SECTION = 5e-16  # cm^2, tuned for simulation scale
+# Threshold inventories (event counts) for flagging common poisons in diagnostics.
+KEY_POISON_THRESHOLDS = {
+    "Xe": 1e20,  # xenon
+    "I": 1e20,  # iodine precursor to xenon
+    "Sm": 5e19,  # samarium
+}