Restore full power when rods are withdrawn

src/reactor_sim/constants.py

@@ -11,6 +11,7 @@ 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 = 0.03  # fraction insertion per second
+CONTROL_ROD_WORTH = 0.03  # delta rho contribution when fully withdrawn
 STEAM_TURBINE_EFFICIENCY = 0.34
 GENERATOR_EFFICIENCY = 0.96
 ENVIRONMENT_TEMPERATURE = 295.0  # K

src/reactor_sim/neutronics.py

@@ -33,7 +33,7 @@ class NeutronDynamics:
     def reactivity(self, state: CoreState, control_fraction: float) -> float:
         rho = (
             self.shutdown_bias +
-            0.02 * (1.0 - control_fraction)
+            constants.CONTROL_ROD_WORTH * (1.0 - control_fraction)
             + temperature_feedback(state.fuel_temperature)
             - fuel_reactivity_penalty(state.burnup)
             - xenon_poisoning(state.neutron_flux)