Valve motor operator improvements

The performance of motor operated valves (MOVs) has been the subject of intense study over the past few years. Significant events resulting from MOV failures, including incapacitation of emergency and/or safe shutdown systems, have been reported frequently by numerous nuclear plant licensees. Evidence points to the fact that the documented failures are largely attributable to deficiencies in equipment design, application, operational and maintenance practices, and in the basic understanding of the equipment. The overall objectives of this project were to identify the specific root causes of selected events related to improper performance of valve motor operators; identify/develop means to correct the performance deficiencies; field test the identified/developed means for corrective action; and provide for the technology transfer of the developed corrective actions. The principal output of this research project was the development of the Intellitorque system, a microprocessor based control and diagnostics system intended for use on valve motor operators. The final report summarizes the Phase I effort, which included the laboratory development and testing of Intellitorque, and the Phase II effort, which has culminated in the installation and field demonstration of Intellitorque at two US nuclear power facilities. 17 refs., 93 figs., 19 tabs