From 5c0ad3fb725f32cff3a60c7f53a6cf8ebe258d91 Mon Sep 17 00:00:00 2001
From: Andrii Prokhorov <prokhorovana@modusx.digital>
Date: Fri, 21 Nov 2025 18:15:11 +0200
Subject: [PATCH] feat: link turbine output to transferred heat

---
 src/reactor_sim/consumer.py | 22 ++++++++++++++--------
 src/reactor_sim/reactor.py  |  2 +-
 src/reactor_sim/thermal.py  |  7 +++++--
 src/reactor_sim/turbine.py  |  4 +++-
 4 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/reactor_sim/consumer.py b/src/reactor_sim/consumer.py
index cb656ee..1c83a56 100644
--- a/src/reactor_sim/consumer.py
+++ b/src/reactor_sim/consumer.py
@@ -14,6 +14,7 @@ class ElectricalConsumer:
     demand_mw: float
     online: bool = False
     power_received_mw: float = 0.0
+    _under_supply_logged: bool = False
 
     def request_power(self) -> float:
         return self.demand_mw if self.online else 0.0
@@ -30,11 +31,16 @@ class ElectricalConsumer:
 
     def update_power_received(self, supplied_mw: float) -> None:
         self.power_received_mw = supplied_mw
-        if supplied_mw < self.request_power():
-            LOGGER.warning(
-                "%s under-supplied: %.1f/%.1f MW",
-                self.name,
-                supplied_mw,
-                self.request_power(),
-            )
-
+        if supplied_mw + 1e-6 < self.request_power():
+            if not self._under_supply_logged:
+                LOGGER.warning(
+                    "%s under-supplied: %.1f/%.1f MW",
+                    self.name,
+                    supplied_mw,
+                    self.request_power(),
+                )
+                self._under_supply_logged = True
+        else:
+            if self._under_supply_logged:
+                LOGGER.info("%s demand satisfied", self.name)
+            self._under_supply_logged = False
diff --git a/src/reactor_sim/reactor.py b/src/reactor_sim/reactor.py
index 9222302..7520c19 100644
--- a/src/reactor_sim/reactor.py
+++ b/src/reactor_sim/reactor.py
@@ -127,7 +127,7 @@ class Reactor:
         self.thermal.step_secondary(state.secondary_loop, transferred)
 
         if self.turbine_active:
-            self.turbine.step(state.secondary_loop, state.turbine, self.consumer)
+            self.turbine.step(state.secondary_loop, state.turbine, self.consumer, steam_power_mw=transferred)
         else:
             state.turbine.shaft_power_mw = 0.0
             state.turbine.electrical_output_mw = 0.0
diff --git a/src/reactor_sim/thermal.py b/src/reactor_sim/thermal.py
index adeda99..5212e1c 100644
--- a/src/reactor_sim/thermal.py
+++ b/src/reactor_sim/thermal.py
@@ -5,6 +5,8 @@ from __future__ import annotations
 from dataclasses import dataclass
 import logging
 
+import math
+
 from . import constants
 from .state import CoolantLoopState, CoreState
 
@@ -14,8 +16,9 @@ LOGGER = logging.getLogger(__name__)
 def heat_transfer(primary: CoolantLoopState, secondary: CoolantLoopState, core_power_mw: float) -> float:
     """Return MW transferred to the secondary loop."""
     delta_t = max(0.0, primary.temperature_out - secondary.temperature_in)
-    conductance = 0.05  # steam generator effectiveness
-    transferred = min(core_power_mw, conductance * delta_t)
+    conductance = 0.15  # steam generator effectiveness
+    efficiency = 1.0 - math.exp(-conductance * delta_t)
+    transferred = min(core_power_mw, core_power_mw * efficiency)
     LOGGER.debug("Heat transfer %.2f MW with ΔT=%.1fK", transferred, delta_t)
     return transferred
 
diff --git a/src/reactor_sim/turbine.py b/src/reactor_sim/turbine.py
index 1303d2d..2202b25 100644
--- a/src/reactor_sim/turbine.py
+++ b/src/reactor_sim/turbine.py
@@ -34,10 +34,12 @@ class Turbine:
         loop: CoolantLoopState,
         state: TurbineState,
         consumer: Optional[ElectricalConsumer] = None,
+        steam_power_mw: float = 0.0,
     ) -> None:
         enthalpy = 2_700.0 + loop.steam_quality * 600.0
         mass_flow = loop.mass_flow_rate * 0.6
-        shaft_power_mw = (enthalpy * mass_flow / 1_000.0) * self.mechanical_efficiency / 1_000.0
+        available_power = max(steam_power_mw, (enthalpy * mass_flow / 1_000.0) / 1_000.0)
+        shaft_power_mw = available_power * self.mechanical_efficiency
         electrical = shaft_power_mw * self.generator_efficiency
         if consumer:
             load_demand = consumer.request_power()