Remote Monitoring of Equipment in Small Modular Reactors

Abstract

Small Modular Reactors (SMR) are being developed by several vendors for remote deployment and for small grid applications. These reactors have the additional advantage of load-following, process heat application, and improved safeguards features. The pressure vessel incorporates most of the critical equipment used for power generation, including the steam generators, control rod drive mechanisms, and the pressurizer. For example, the reactor coolant pumps may be internal to the vessel or mounted on the vessel without any additional piping. The control rod drive mechanisms in many SMRs are also internal to the reactor vessel. These features limit the in-vessel instrumentations, thus making it a challenge for monitoring critical in-vessel components and measurement of process variables. On-line monitoring of SMR components, using electrical signature analysis (ESA), is presented and application to an experimental flow loop is outlined. Both stationary and non-stationary signal processing techniques are applied to pump-motor signatures, vibration measurements, and pump discharge pressure. The pump is a submersible device which is fitted with underwater accelerometers. The results of analysis indicate a high correlation between the motor current and pump discharge pressure. Furthermore, frequency domain analysis indicates that varying vibration bands correlate with the features of motor current signatures in the power spectral density plots. A physics model of an integral pressurized water reactor has been developed and used to simulate anomalies in sensors, equipment, and in the reactor dynamics.