diff --git a/src/reactor_sim/commands.py b/src/reactor_sim/commands.py
index c1a7ec3..99cd0df 100644
--- a/src/reactor_sim/commands.py
+++ b/src/reactor_sim/commands.py
@@ -25,6 +25,8 @@ class ReactorCommand:
     secondary_pumps: dict[int, bool] | None = None
     generator_units: dict[int, bool] | None = None
     generator_auto: bool | None = None
+    primary_relief: bool | None = None
+    secondary_relief: bool | None = None
     maintenance_components: tuple[str, ...] = tuple()
 
     @classmethod
diff --git a/src/reactor_sim/dashboard.py b/src/reactor_sim/dashboard.py
index f4b38f7..74706c1 100644
--- a/src/reactor_sim/dashboard.py
+++ b/src/reactor_sim/dashboard.py
@@ -74,6 +74,7 @@ class ReactorDashboard:
                 [
                     DashboardKey("b/v", "Toggle generator 1/2"),
                     DashboardKey("x", "Toggle generator auto"),
+                    DashboardKey("l/;", "Toggle relief primary/secondary"),
                     DashboardKey("B/V", "Maintain generator 1/2"),
                 ],
             ),
@@ -162,6 +163,10 @@ class ReactorDashboard:
                 self._toggle_generator_unit(0)
             elif ch in (ord("v"), ord("V")):
                 self._toggle_generator_unit(1)
+            elif ch == ord("l"):
+                self._queue_command(ReactorCommand(primary_relief=not self.reactor.primary_relief_open))
+            elif ch == ord(";"):
+                self._queue_command(ReactorCommand(secondary_relief=not self.reactor.secondary_relief_open))
             elif ch in (ord("x"), ord("X")):
                 self._queue_command(ReactorCommand(generator_auto=not self.reactor.generator_auto))
             elif ch in (ord("t"), ord("T")):
@@ -375,6 +380,7 @@ class ReactorDashboard:
                 ("Inlet Temp", f"{state.primary_loop.temperature_in:7.1f} K"),
                 ("Outlet Temp", f"{state.primary_loop.temperature_out:7.1f} K (Target {constants.PRIMARY_OUTLET_TARGET_K:4.0f})"),
                 ("Pressure", f"{state.primary_loop.pressure:5.2f}/{constants.MAX_PRESSURE:4.1f} MPa"),
+                ("Relief", "OPEN" if self.reactor.primary_relief_open else "CLOSED"),
             ],
         )
         self._draw_section(
@@ -392,6 +398,7 @@ class ReactorDashboard:
                 ("Outlet Temp", f"{state.secondary_loop.temperature_out:7.1f} K (Target {constants.SECONDARY_OUTLET_TARGET_K:4.0f})"),
                 ("Pressure", f"{state.secondary_loop.pressure:5.2f}/{constants.MAX_PRESSURE:4.1f} MPa"),
                 ("Steam Quality", f"{state.secondary_loop.steam_quality:5.2f}/1.00"),
+                ("Relief", "OPEN" if self.reactor.secondary_relief_open else "CLOSED"),
             ],
         )
 
diff --git a/src/reactor_sim/reactor.py b/src/reactor_sim/reactor.py
index 7949948..9c4f174 100644
--- a/src/reactor_sim/reactor.py
+++ b/src/reactor_sim/reactor.py
@@ -45,6 +45,8 @@ class Reactor:
     shutdown: bool = False
     meltdown: bool = False
     generator_auto: bool = False
+    primary_relief_open: bool = False
+    secondary_relief_open: bool = False
     poison_alerts: set[str] = field(default_factory=set)
     maintenance_active: set[str] = field(default_factory=set)
 
@@ -96,6 +98,8 @@ class Reactor:
         self.shutdown = True
         self.meltdown = False
         self.generator_auto = False
+        self.primary_relief_open = False
+        self.secondary_relief_open = False
         self.primary_pump_active = False
         self.secondary_pump_active = False
         self.primary_pump_units = [False] * len(self.primary_pump_units)
@@ -321,6 +325,11 @@ class Reactor:
                 pump_state.pressure = state.secondary_loop.pressure
                 pump_state.status = "STOPPING" if pump_state.flow_rate > 1.0 else "OFF"
 
+        if self.primary_relief_open:
+            state.primary_loop.pressure = max(0.1, saturation_pressure(state.primary_loop.temperature_out))
+        if self.secondary_relief_open:
+            state.secondary_loop.pressure = max(0.1, saturation_pressure(state.secondary_loop.temperature_out))
+
         self.thermal.step_core(state.core, state.primary_loop, total_power, dt)
         if not self.secondary_pump_active or state.secondary_loop.mass_flow_rate <= 1.0:
             transferred = 0.0
@@ -459,6 +468,10 @@ class Reactor:
             self._set_turbine_state(False)
         if command.generator_auto is not None:
             self.generator_auto = command.generator_auto
+        if command.primary_relief is not None:
+            self.primary_relief_open = command.primary_relief
+        if command.secondary_relief is not None:
+            self.secondary_relief_open = command.secondary_relief
         if command.power_setpoint is not None:
             self.control.set_power_setpoint(command.power_setpoint)
         if command.rod_manual is not None:
@@ -699,6 +712,8 @@ class Reactor:
             "shutdown": self.shutdown,
             "meltdown": self.meltdown,
             "generator_auto": self.generator_auto,
+            "primary_relief_open": self.primary_relief_open,
+            "secondary_relief_open": self.secondary_relief_open,
             "maintenance_active": list(self.maintenance_active),
             "generators": [
                 {
@@ -732,6 +747,8 @@ class Reactor:
         self.shutdown = metadata.get("shutdown", self.shutdown)
         self.meltdown = metadata.get("meltdown", self.meltdown)
         self.generator_auto = metadata.get("generator_auto", self.generator_auto)
+        self.primary_relief_open = metadata.get("primary_relief_open", self.primary_relief_open)
+        self.secondary_relief_open = metadata.get("secondary_relief_open", self.secondary_relief_open)
         maint = metadata.get("maintenance_active")
         if maint is not None:
             self.maintenance_active = set(maint)