Stop pressurizer pumping a cold loop

src/reactor_sim/reactor.py

@@ -309,8 +309,7 @@ class Reactor:
             state.primary_loop.mass_flow_rate = self._ramp_value(
                 state.primary_loop.mass_flow_rate, 0.0, dt, self.primary_pump.spool_time
             )
-            pressurizer_floor = constants.PRIMARY_PRESSURIZER_SETPOINT_MPA - 0.5 if self.pressurizer_level > 0.05 else 0.5
-            target_pressure = max(pressurizer_floor, saturation_pressure(state.primary_loop.temperature_out))
+            target_pressure = max(0.5, saturation_pressure(state.primary_loop.temperature_out))
             state.primary_loop.pressure = self._ramp_value(
                 state.primary_loop.pressure, target_pressure, dt, self.primary_pump.spool_time
             )
@@ -551,6 +550,8 @@ class Reactor:
         return max(0.0, min(1.0, available / constants.NPSH_REQUIRED_MPA))
 
     def _apply_pressurizer(self, primary: CoolantLoopState, dt: float) -> None:
+        if self.shutdown and primary.mass_flow_rate <= 100.0:
+            return
         target = constants.PRIMARY_PRESSURIZER_SETPOINT_MPA
         band = constants.PRIMARY_PRESSURIZER_DEADBAND_MPA
         heat_rate = constants.PRIMARY_PRESSURIZER_HEAT_RATE_MPA_PER_S

tests/test_pressurizer.py

@@ -5,14 +5,15 @@ from reactor_sim.commands import ReactorCommand
 def test_pressurizer_raises_pressure_with_level():
     reactor = Reactor.default()
     state = reactor.initial_state()
-    state.primary_loop.pressure = 5.0
+    state.primary_loop.pressure = 0.5
     reactor.pressurizer_level = 0.8
     reactor.primary_pump_active = False
     reactor.secondary_pump_active = False
+    reactor.shutdown = False
 
-    reactor.step(state, dt=1.0, command=ReactorCommand.scram_all())
+    reactor.step(state, dt=1.0, command=ReactorCommand())
 
-    assert state.primary_loop.pressure > 5.0
+    assert state.primary_loop.pressure > 0.5
     assert reactor.pressurizer_level < 0.8