Motor-Operated Valves (MOVs) in nuclear plants have an equipment qualification (EQ) life of 2000 cycles. Historically, nuclear generating stations have not counted actuator cycles. As nuclear plants age beyond 30 years and licenses are extended from 40 to 60 years, the accumulated actuator operational cycles have become an issue. Without hard data, plants are not able to “prove” that actuator fatigue cycle count is less than 2000 cycles. The only viable option to address this issue is actuator replacement. Actuator replacement is expensive and frequently require long lead times for procurement. Nuclear plants generally have fifty to one hundred qualified actuators and replacing all qualified actuators is prohibitively expensive.
The questions is simply how to deliver the nuclear promise without wholesale replacement of actuators and expending significant capital or O&M dollars.
Paper published with permission.
