Thermal-Hydraulic Twin
A thermal-hydraulic twin tracks heat generation, transport, and removal through the coolant loops that keep the machine within limits.
Managing the heat
A fusion machine generates intense heat, in the plasma-facing surfaces, in the blanket from neutron deposition, and in the magnets, and that heat must be carried away by coolant loops without any surface exceeding its limit. A thermal-hydraulic twin tracks the generation, transport, and removal of this heat, estimating temperatures and flows throughout, including at points no sensor can reach.
What it models
- Heat sources: neutron deposition, plasma exhaust to surfaces, magnet losses
- Conduction through solid structures to the coolant channels
- Convection in the coolant and its flow distribution
- Heat rejection at the plant's ultimate heat sink
Reconstructing internal temperatures
The temperatures that matter most, at plasma-facing surfaces and inside structures, are the hardest to measure. The twin reconstructs them from accessible measurements, coolant inlet and outlet temperatures, flow rates, and the neutron heating from the neutronics twin, through a thermal model. Reduced-order thermal models make this fast enough for the loop while staying interpretable. See reduced-order models.
Detecting degradation
Over time, cooling degrades: surfaces foul, channels partially block, pumps wear. Because the twin knows what the temperatures should be for a given heat load and flow, a growing gap between predicted and measured temperatures reveals degradation and helps localize it, feeding predictive maintenance before a limit is threatened. See predictive maintenance.
In the Kronos machines
For the Hyperion breeder, the thermal-hydraulic twin manages the large neutron-driven heat load in the blanket and the exhaust load on plasma-facing surfaces. For the burner, with its low neutron fraction of 5.44 percent, more of the heat arrives as charged-particle exhaust and much of the energy is handled by direct conversion, changing the balance the thermal twin tracks. Both are built on validated thermal-hydraulic models now, with calibration to real hardware after the machines operate. See neutronics twin.