A procedure in which the speed of a turbine is held constant for a specified length of time; a method used to bring steam-to-metal temperature mismatches back to normal.

A procedure in which the speed of a turbine is held constant for a specified length of time; a method used to bring steam-to-metal temperature mismatches back to normal.

• A. Heat soak
• B. Slow ramp
• C. Isothermal hold
• D. Temperature equalization

Answer: (A)

The idea being tested is using a controlled heat-transfer pause to let temperatures even out and reduce thermal stress. Holding the turbine at a fixed speed for a set time allows steam-driven heat to continue flowing while the metal components diffuse heat more uniformly, bringing steam-to-metal temperature differences back toward normal. This specific pause is known as a heat soak, because the system is effectively “soaking” at steady conditions to equalize temperatures. Other terms describe different actions or end results—changing speed gradually (a slow ramp) rather than keeping it constant, or focusing on maintaining a constant temperature (isothermal hold) or stating the outcome (temperature equalization) rather than the method itself.