Innovative testing of motor operated valves

All nuclear utilities have spent considerable resources over the last 5 to 10 years improving Motor Operated Valve (MOV) testing programs. These programs for the most part have been geared toward four primary objectives. (1) Establish the design basis for the MOV. (2) Review installed hardware and switch settings to determine if the MOV is capable of fulfilling its design basis function. (3) Overhaul the MOV-identifying component material discrepancies and establishing a known first-rate condition. (4) Test the MOV under static and differential pressure conditions to assure the MOV is properly setup to carry out its design basis function. Although there an many other aspects of establishing an effective program (training, documentation, maintenance) the above represents the basic strategy used to develop MOV programs. These programs were in part developed in response to NRC Generic Letter 89-10. Generic Letter 89-10 was issued because available data on MOVs indicated that MOVs were much more likely to fail under design bases events that had previously been estimated