Restore three turbines and update controls

src/reactor_sim/dashboard.py

@@ -52,8 +52,8 @@ class ReactorDashboard:
             DashboardKey("p", "Toggle primary pump"),
             DashboardKey("o", "Toggle secondary pump"),
             DashboardKey("t", "Toggle turbine"),
-            DashboardKey("1/2", "Toggle turbine units 1-2"),
-            DashboardKey("y/u", "Maintain turbine 1/2"),
+            DashboardKey("1/2/3", "Toggle turbine units 1-3"),
+            DashboardKey("y/u/i", "Maintain turbine 1/2/3"),
             DashboardKey("c", "Toggle consumer"),
             DashboardKey("r", "Reset & clear state"),
             DashboardKey("m", "Maintain primary pump"),
@@ -162,6 +162,8 @@ class ReactorDashboard:
                 self._queue_command(ReactorCommand.maintain("turbine_1"))
             elif ch in (ord("u"), ord("U")):
                 self._queue_command(ReactorCommand.maintain("turbine_2"))
+            elif ch in (ord("i"), ord("I")):
+                self._queue_command(ReactorCommand.maintain("turbine_3"))
 
     def _queue_command(self, command: ReactorCommand) -> None:
         if self.pending_command is None:
@@ -321,8 +323,8 @@ class ReactorDashboard:
         tips = [
             "Start pumps before withdrawing rods.",
             "Bring turbine and consumer online after thermal stabilization.",
-            "Toggle turbine units (1/2) for staggered maintenance.",
-            "Use m/n/k/y/u to request maintenance (stop equipment first).",
+            "Toggle turbine units (1/2/3) for staggered maintenance.",
+            "Use m/n/k/y/u/i to request maintenance (stop equipment first).",
             "Press 'r' to reset/clear state if you want a cold start.",
             "Watch component health to avoid automatic trips.",
         ]

src/reactor_sim/failures.py

@@ -56,7 +56,7 @@ class HealthMonitor:
             "primary_pump": ComponentHealth("primary_pump"),
             "secondary_pump": ComponentHealth("secondary_pump"),
         }
-        for idx in range(2):
+        for idx in range(3):
             name = f"turbine_{idx + 1}"
             self.components[name] = ComponentHealth(name)
         self.failure_log: list[str] = []

src/reactor_sim/reactor.py

@@ -59,7 +59,7 @@ class Reactor:
             secondary_pump=Pump(nominal_flow=16_000.0, efficiency=0.85),
             thermal=ThermalSolver(),
             steam_generator=SteamGenerator(),
-            turbines=[Turbine() for _ in range(2)],
+            turbines=[Turbine() for _ in range(3)],
             atomic_model=atomic_model,
             consumer=ElectricalConsumer(name="Grid", demand_mw=800.0, online=False),
             health_monitor=HealthMonitor(),