Vibration-based Condition Diagnosis of Air-Supply and Exhaust Fans in HVAC System of Domestic Nuclear Fuel Cycle Facility

Heating, Ventilation, and Air Conditioning (HVAC) systems are typically viewed as secondary maintenance targets because their failures usually result in only temporary discomfort and inconvenience for indoor workers, rather than causing facility damage or safety hazards. However, in nuclear fuel cycle facilities, HVAC systems function as containment systems to isolate radioactive materials, making them essential for facility safety. Among these systems, the air-supply and exhaust fans are the most critical components for maintaining negative pressure conditions, as their reliability directly affects overall facility safety. Therefore, implementing Fault Detection and Diagnosis (FDD) and Condition-Based Maintenance (CBM) for these fans is crucial to enhancing the safety and reliability of the facility. This study conducted a vibration-based diagnosis of the air-supply and exhaust fans in a domestic nuclear fuel cycle facility to assess the overall integrity of the fan system, which includes an impeller, bearings, pulleys, belts, and a motor. The results showed that the vibration-based FDD method effectively detects high vibrations, identifies failure types, and pinpoints faulty components. Considering the increasing demand for safety enhancements in nuclear fuel cycle facilities and the growing importance of CBM for their HVAC systems, adopting vibration-based CBM technology for air-supply and exhaust fans is expected to further improve facility safety. Additionally, transitioning from a breakdown maintenance approach to a CBM-based proactive strategy is anticipated to enhance the efficiency of nuclear fuel cycle facility management.