PT PLN Nusantara Power UP Tenayan in Pekanbaru operates a power plant that relies on the Circulating Water Pump (CWP) as a vital part of the cooling system. Based on the results of field observations and interviews, failures in the CWP instrumentation system can cause downtime and reduce operating efficiency, but reliability studies are still limited. This study aims to analyze the reliability of the CWP instrumentation system using the Failure Mode and Effect Analysis (FMEA) method. Data were obtained through field observations and technician interviews, then analyzed based on Severity, Occurrence, and Detection parameters. The analysis identified eight main components, with Risk Priority Number (RPN) values all below the 200 threshold. Based on the results of the FMEA calculation, the limit switch component has the highest RPN value of 160 with the potential for downtime reaching 2 to 3 hours per occurrence. The application of FMEA is proven effective to reduce the risk of failure by 25% based on estimated technical evaluation and failure history.