Restore full power when rods are withdrawn

tests/test_simulation.py

@@ -144,3 +144,19 @@ def test_primary_pumps_spool_up_over_seconds():
         reactor.step(state, dt=1.0, command=ReactorCommand(coolant_demand=1.0))
 
     assert state.primary_loop.mass_flow_rate == pytest.approx(target_flow, rel=0.1)
+
+
+def test_full_rod_withdrawal_reaches_gigawatt_power():
+    reactor = Reactor.default()
+    state = reactor.initial_state()
+    reactor.shutdown = False
+    reactor.control.manual_control = True
+    reactor.control.rod_fraction = 0.0
+    reactor.primary_pump_active = True
+    reactor.secondary_pump_active = True
+
+    for _ in range(60):
+        reactor.step(state, dt=1.0)
+
+    assert state.core.power_output_mw > 2_000.0
+    assert state.core.fuel_temperature > 400.0