Modifications to existing equipment combat valve damage from fast-closing actuators

The methods to prevent motor-actuated valves used in nuclear power plants from being damaged as a result of high-speed actuator action are considered. Various other causes contributing to damage are pointed out. The ways to improve actuator efficiency and to incorporate inertia-absorbing Belleville springs in the drive-sleeve assembly are discussed. It is concluded that the Belleville springs for the drive-sleeve are large, and there is a cost impact upon the actuator, but, where damage is possible through high-speed operation, they offer an excellent solution