Troubleshooting complex issues in a nuclear facility requires a blend of precision, technical expertise, and strict adherence to safety protocols. One specific incident involved a sudden drop in reactor coolant levels, which could potentially lead to a reactor shutdown if not addressed swiftly. Using diagnostic tools like the reactor's internal sensors and real-time data analytics, we were able to pinpoint a minor leak in one of the coolant pipes. This issue was initially elusive because the leak was intermittent and only occurred under specific pressure conditions. For problem-solving, we employed a methodical approach: first verifying the data integrity from our sensors, then isolating different sections of the coolant system to localize the issue. After identifying the problematic section, non-destructive testing techniques were used to confirm the presence of a crack. A high-resolution ultrasonic flow meter played a crucial role, as it helped confirm minuscule variations in flow that weren’t obvious initially. The repair was scheduled promptly during a planned maintenance outage, minimizing disruption to the facility's operations. This scenario underscored the importance of integrating sophisticated diagnostic tools with a structured troubleshooting methodology to ensure safety and efficiency in nuclear facility operations.