Fast and Efficient: A New Electric Actuator Diagnostics System Rolls Out at Russian Nuclear Power Plants
In Russian nuclear power plants are moving to a new level of maintenance. A new diagnostic system for electric actuators is set to be used to inspect thousands of drives without dismantling equipment or shutting down operations.
What Was Developed at MEPhI
Researchers at the National Research Nuclear University MEPhI have completed the development of a mobile system known as SOD EPA (Operational Diagnostics System for Electric Actuators). The portable unit connects directly to an actuator’s power cabinet and measures current, voltage, power, and other parameters. Software running on a tablet or computer analyzes the data immediately and generates a technical condition assessment for the actuator.
To determine actual torque, the system uses an additional sensor mounted directly on the actuator itself. This makes it possible to carry out measurements without removing the drive and transporting it to a test bench. What previously required dismantling, logistics, bench testing, and reinstallation can now be done on site during routine adjustment work.
Why This Changes Nuclear Plant Maintenance
At a large nuclear power plant, thousands of electric actuators control valves across kilometers of piping. Traditionally, checking them meant dismantling each actuator, testing it on a bench, and reinstalling it, a process that extended scheduled maintenance outages and increased costs.
SOD EPA dramatically reduces both the time and cost of diagnostics. Measurements are performed without disassembly or relocation of the actuator. Accuracy also improves, because torque and performance characteristics are measured under real operating conditions rather than in an artificial test environment.
Maintenance teams gain a practical tool for regular condition monitoring that fits into existing repair schedules and reduces the workload on technical staff.
How the New System Improves Safety
Electric actuators are safety-critical components. Their reliability determines whether a plant can open or close coolant flow in time, respond correctly to emergency modes, and keep key parameters within design limits. Any actuator failure creates risks for equipment and potentially for the safety of the power unit itself.
Regular operational diagnostics make it possible to detect mechanical wear, gearbox degradation, reduced torque, and other deviations long before a failure occurs. This allows problematic actuators to be repaired or replaced in advance, preventing incidents rather than reacting to them.
Diagnostic data will also be used to support decisions on life extension, maintenance planning, and modernization. Safety no longer relies solely on fixed schedules and spot checks – it is reinforced by continuous, evidence-based monitoring of actual equipment condition.
Digital Systems and Predictive Diagnostics
The MEPhI development fits squarely into a global trend. Leading nuclear operators and regulators worldwide are shifting toward online condition monitoring and predictive diagnostics.
In Russia, the system is being aligned with the concept of smart maintenance. Plans include integration with digital monitoring platforms and predictive diagnostics systems at nuclear power plants. Data from SOD EPA will become part of an end-to-end digital equipment model, where each actuator has a measurement history and a forecasted remaining service life.
Testing and Deployment Plans
The system has already been tested at the Novovoronezh Nuclear Power Plant and received positive evaluations. Its use significantly shortens diagnostic time and reduces the workload on maintenance teams.
SOD EPA is expected to be incorporated into standard maintenance practices at Russian nuclear plants. Rosenergoatom and specialized research organizations plan to include such systems in the list of recommended diagnostic tools for operating companies. Industrial production of the equipment will be established, along with training programs for plant personnel, so that by the end of the decade mobile diagnostics of electric actuators becomes an industry standard.
