diff --git a/src/reactor_sim/failures.py b/src/reactor_sim/failures.py
index 1342d95..76972c3 100644
--- a/src/reactor_sim/failures.py
+++ b/src/reactor_sim/failures.py
@@ -89,12 +89,18 @@ class HealthMonitor:
         sec_units = list(secondary_units)
         prim_states = state.primary_pumps or []
         sec_states = state.secondary_pumps or []
+        primary_temp = getattr(state.primary_loop, "temperature_out", 295.0)
+        secondary_temp = getattr(state.secondary_loop, "temperature_out", 295.0)
+        primary_heat_factor = max(0.0, (primary_temp - 600.0) / 400.0)  # harsher wear only when very hot
+        secondary_heat_factor = max(0.0, (secondary_temp - 520.0) / 300.0)
         for idx, active in enumerate(prim_units):
             comp = self.component(f"primary_pump_{idx + 1}")
             if idx < len(prim_states) and active:
                 flow = prim_states[idx].flow_rate
                 flow_ratio = 0.0 if flow <= 0 else min(1.0, flow / 9_000.0)
-                comp.degrade((0.0002 + (1 - flow_ratio) * 0.005) * dt)
+                low_flow_penalty = (1 - flow_ratio) * 0.001
+                rate = (0.0001 + low_flow_penalty) * (1 + primary_heat_factor)
+                comp.degrade(rate * dt)
             else:
                 comp.degrade(0.0)
         for idx, active in enumerate(sec_units):
@@ -102,7 +108,9 @@ class HealthMonitor:
             if idx < len(sec_states) and active:
                 flow = sec_states[idx].flow_rate
                 flow_ratio = 0.0 if flow <= 0 else min(1.0, flow / 8_000.0)
-                comp.degrade((0.0002 + (1 - flow_ratio) * 0.004) * dt)
+                low_flow_penalty = (1 - flow_ratio) * 0.0008
+                rate = (0.0001 + low_flow_penalty) * (1 + secondary_heat_factor)
+                comp.degrade(rate * dt)
             else:
                 comp.degrade(0.0)