Cooling Water and Heat Rejection Control
Cooling loops carry heat from magnets, heating systems, and plasma-facing components to a heat sink, regulated to hold every component in its window.
Many loops, one job
A fusion plant has numerous cooling circuits: room-temperature water for power supplies, heating sources, and pumps; higher-grade coolant for plasma-facing components and the blanket; and the cryogenic loops for the magnets. Each carries heat from a component to a heat exchanger and ultimately to a heat sink such as a cooling tower or water body. Control keeps each loop's flow and temperature within its component's limits.
Regulation basics
A cooling loop is regulated by controlling pump speed, valve positions, and heat-exchanger duty to hold a target outlet temperature or component temperature. Because heat loads swing with the operating cycle, the loops must follow the load; feedforward from the operating schedule plus feedback on measured temperatures gives a stable response without large excursions.
Interlocks
Cooling is a protection function for hot components. Loss of flow to a plasma-facing component, a heating source, or a power supply is an interlock condition that reduces or stops the heat source before damage occurs. Flow, pressure, and temperature sensors feed both control and interlock chains, with the interlock path kept independent so a control fault cannot defeat protection.
- Separate loops for supplies, PFCs, blanket, and magnets
- Pump speed, valves, and exchangers hold target temperatures
- Feedforward from the cycle plus feedback trim
- Loss of flow interlocks the heat source
Heat rejection
At the end of every loop the heat must leave the plant to a sink, and the rejection system's capacity sets an overall limit on sustained operation. Control balances the rejection duty against ambient conditions. In the Kronos designs the breeder rejects blanket heat while the burner rejects a smaller thermal load because most of its energy is converted directly; both are design and simulation cases described here without any cost or performance-in-service claims.
Cooling control is the unglamorous backbone that keeps every heat-loaded component alive.