On-Power Fuelling Machine for Advanced Heavy Water Reactor

Advanced Heavy Water Reactor (AHWR) is a thorium-based vertical, pressure tube type reactor. The reactor needs to be refuelled periodically mainly to maintain requisite reactivity in reactor. A dedicated, remotely operated on-power Fuelling Machine (FM) is used for this purpose. The FM removes spent fuel from reactor, replaces it with new fuel and finally transfers the spent fuel to fuel transfer system of reactor. During refuelling, the FM interacts with high temperature and high-pressure coolant channel and maintains the pressure boundary during refuelling. The FM consists of various innovative design features like limiting load on coolant channel during refuelling, maintaining isolation between V1 and V2 volumes, handling of long fuel assembly, maintaining cooling and shielding of fuel, compact configuration, etc. Safe handling of fuel is ensured by incorporating adequate safety features to avoid fall of fuel during handling. This paper covers the design requirements, challenges and features of AHWR FM.