Abstract: An improved measurement apparatus employs a support that includes a housing and that further includes a follower that is movably situated on the support. The follower is biased in a direction generally away from the housing. The housing and follower are receivable between a spring/dimple pair, and a sensor detects the distance between the housing and the follower when interposed between the spring and dimple. An indicator apparatus employs the signal to output and indication that is representative of the amount of compressive loading that will be applied to a fuel rod by the spring/dimple pair, and the indication is based at least in part upon the distance between the portion of the housing that is engaged with the dimple and the portion of the follower that is engaged with the spring.

Abstract: A thermal actuator for a rotating shaft shutdown seal that has a piston with a portion of its axial length enclosed within a chamber shell with a material that expands upon a rise in temperature. The portion of the actual length of the piston within the chamber has at least two different diameters with the larger diameter leading in the direction of travel of the piston. Upon a rise in temperature, expansion of the material surrounding the piston within the chamber creates a force on the piston in the desired direction of travel. Below a preselected temperature the piston is positively locked with a passive release when the preselected temperature is reached.

Abstract: An improved measurement apparatus employs a support that includes a housing and that further includes a follower that is movably situated on the support. The follower is biased in a direction generally away from the housing. The housing and follower are receivable between a spring/dimple pair, and a sensor detects the distance between the housing and the follower when interposed between the spring and dimple. An indicator apparatus employs the signal to output and indication that is representative of the amount of compressive loading that will be applied to a fuel rod by the spring/dimple pair, and the indication is based at least in part upon the distance between the portion of the housing that is engaged with the dimple and the portion of the follower that is engaged with the spring.

Abstract: A thermal actuator for a rotating shaft shutdown seal that has a piston with a portion of its axial length enclosed within a chamber shell with a material that expands upon a rise in temperature. The portion of the actual length of the piston within the chamber has at least two different diameters with the larger diameter leading in the direction of travel of the piston. Upon a rise in temperature, expansion of the material surrounding the piston within the chamber creates a force on the piston in the desired direction of travel. Below a preselected temperature the piston is positively locked with a passive release when the preselected temperature is reached.

Abstract: A thermal actuator for a rotating shaft shutdown seal that has a piston with a portion of its axial length enclosed within a cylinder shell with a material, such as a fusible link that changes state or deforms above a given temperature, interposed between a closed end of the cylinder and one end of the piston. The piston is spring biased toward the material and moves toward the closed end of the cylinder when the given temperature is reached and the deformation or change of state of the material makes room for the piston to move toward the closed end. Movement of the piston is transferred through a piston rod to activate the seal.

Abstract: A thermal actuator for a rotating shaft shutdown seal that has a piston with a portion of its axial length enclosed within a cylinder shell with a material, such as a fusible link that changes state or deforms above a given temperature, interposed between a closed end of the cylinder and one end of the piston. The piston is spring biased toward the material and moves toward the closed end of the cylinder when the given temperature is reached and the deformation or change of state of the material makes room for the piston to move toward the closed end. Movement of the piston is transferred through a piston rod to activate the seal.