Fuel assembly reconstitution at the Prairie Island PWR using a remotely controlled assembly repair machine

The paper gives a description of a fully mechanized assembly repair system recently developed by Advanced Nuclear Fuels Corporation (ANF) for the safe and rapid repair or reconstitution of damaged or failed assemblies. The REPAR (Remote Poolside Assembly Repair) system, consisting of a large X-Y table and a fuel rod extraction mast, is placed on top of the fuel storage racks in the spent fuel pool and repairs or reconstitutions are carried out with the assembly being placed in the storage cell underneath the machine. The underwater equipment is remotely operated from a control console placed on the fuel pool deck. The use of the REPAR system and the work procedures employed to reconstitute 3 fuel assemblies that were damaged during core loading at the Prairie Island Nuclear plant are described. Fuel rods were transferred at a rate of approximately 20 rods per hour. A 14x14 fuel assembly could be completely reconstituted in as little as 13 hours. The work at Prairie Island demonstrated that the REPAR machine can be used during short refueling outages to repair or reconstitute fuel assemblies with minimum impact on plant critical path schedules. (author). 4 figs