Abstract: A system for operating a turbine includes a rotating component and a non-rotating component separated from the rotating component by a clearance. A first actuator is connected to the non-rotating component, and the first actuator comprises a shape-memory alloy. A method for operating a turbine includes sensing a parameter reflective of a clearance between a non-rotating component and a rotating component and generating a parameter signal reflective of the clearance. The method further includes generating a control signal to at least one actuator based on the parameter signal and moving at least a portion of the non-rotating component relative to the rotating component to change the clearance.

Abstract: A seal assembly for providing sealing between a movable cylindrical body and a housing body comprises separate sealing mechanisms for providing static and dynamic sealing. The seal assembly is associated in fixed relationship with either the cylindrical body or the housing body and provides a static seal with the body it is associated with and a dynamic seal with the body that moves relative to the seal assembly. The static sealing mechanism is temperature-activated so that within the operating temperature range, a metallic member of the static seal mechanism is pressed tightly against the associated body to provide a fluid tight static seal. The temperature-activation is caused by the metallic member having a different thermal expansion coefficient than the associated body. The dynamic seal may employ known dynamic sealing mechanisms such as spring-energized seals, interference fit seals, and/or temperature-activated seals.