Reduction in surveillance requirements for Limitorque valve operators

The frequency of the electrical and lubrication inspections for Limitorque Motor Operated Valves (MOVs) at all ComEd nuclear stations has been established at 36 months or every other refueling outage. ComEd wanted to extend the surveillance frequency to every 54 months or third refueling outage. This surveillance activity could then be performed at the same time as other MOV inspection activities as committed to by ComEd in their response to Generic Letter (GL) 89-10. To justify extension of the surveillance frequency to every 54 months, the surveillance records for the safety-related MOVs at all ComEd nuclear stations were compiled, reviewed and evaluated, as well as industry data from the Institute of Nuclear Power Operations (INPO) and the Electrical Power Research Institute (EPRI). In addition, lubricant testing was performed at ComEd's System Material Analysis Department (SMAD) test facility and at National Technical Services (NTS) Acton laboratory. This paper will discuss the results of the review, supplemented by tests, that showed that there is no indication of any age-related degradation of the MOVs electrical items and lubricant over a 54 month interval. Therefore, the existing 36 month interval could be extended to 54 months or every third refueling outage. The total savings to ComEd by reducing the surveillance over the remaining life of the plants is estimated at about $11 million