January-February 2019 NPJ

44 NuclearPlantJournal.com Nuclear Plant Journal, January-February 2019 Performance Monitoring... ( Continued from page 43) manifest themselves in spectral changes as compared to baseline measurements. • Use empirical correlations developed in the laboratory to translate the changes in emissions spectrum to degraded components. Table 2 lists examples of electrical and I&C components of nuclear power plants together with their electromagnetic characteristics that can change with degradation. SECA Applications and Benefits Predictive maintenance programs for rotating machinery have successfully used condition monitoring technologies to reduce maintenance costs, improve equipment performance, and prevent unscheduled downtime in a variety of applications and industries. SECA will offer the same benefits to the nuclear power industry for condition monitoring of electrical and I&C equipment. Table 3 shows a few LERs on failure of typical nuclear power plant equipment that may be detectable with SECA. With SECA, nuclear plant operators will be able to more proactively maintain their electrical and I&C equipment, improve plant safety, reduce risks to operation, and limit the number and duration of unplanned shutdowns. In addition, digital I&C components may gain wider adoption in the nuclear industry if measures are in place to help ensure their reliability. These benefits will help make the existing fleet of nuclear reactors more competitive, add to the prosperity of next generation nuclear reactors, and thereby extend substantial benefits to the general public in reduced electricity rates and safer nuclear energy with its accompanying environmental benefits. The applications of SECA is not limited to the commercial nuclear industry. Any process which employs electrical and I&C equipment for safety or process control can benefit from SECA. For example, emission monitoring technology can be used in the aerospace industry to determine the health of flight control systems, in refining and chemical production facilities to troubleshoot electrical equipment failures, and in telecommunications systems to ensure reliable service to consumers. Progress to Date The following laboratory work has been completed in a Phase I project towards development of SECA. This work will be continued under the scope of Phase I to be followed in late 2019 or early 2020 with a Phase II project to complete the development and testing of SECA and its implementation in the nuclear industry. 1. Performed initial laboratory experiments by degrading a capacitor in a switched mode power supply as a proof of concept. Figure 1 shows the decrease in capacitance as the capacitor was thermally degraded at a temperature of 220°F and the associated emission data measured on the output of the power supply. As seen in the data, the power supply with the degraded capacitor shows a change in its electromagnetic signature (increase in amplitude) from that of the power supply with the healthy capacitor. Therefore, if baseline emission signatures are measured and trended over time, variations in the equipment’s electromagnetic signature can be analyzed to determine impending component failures. Table 2. Examples of Nuclear Power Plant Electrical and I&C Equipment and their Electromagnetic Characteristics. Table 3. Representative LERs with Failure Classification. Figure 1. Frequency Response of a Thermally Degraded Capacitor in a Power Supply.