Spent fuel characterization program in Jose Cabrera nuclear power plant

Jose Cabrera Nuclear Power Plant (NPP) is a 14x14 PWR reactor built in 1964 in Spain (160 MWe). The commercial operation started in 1969 and finished in 2006. During year 2009, 377 fuel assemblies from cycles 11 to 29 have been stored in 12 containers HI-STORM 100, and positioned in an Interim Spent Fuel Storage Installation built near the NPP. The spent fuel characterization and classification is a critical and complex activity that could impact all the storage process. As every container has a number of positions for damaged fuel, the loading plans and the quantity of containers depends on the total fuels classified as damaged. The classification of the spent fuel in Jose Cabrera has been performed on the basis of the Interim Staff Guidance ISG-1 from USNRC, 'Damaged Fuel'. As the storage system should assure thermal limitations, criticality control, retrievability, confinement and shielding for radioactive protection, the criteria analyzed for every spent fuel have been the existence/non existence of fuel leaks; damage that could affect the criticality analysis (as missing fuel pins) and any situation that could affect the future retrievability, as defects on the top nozzle. The first classification was performed based upon existing core records. If there were no indication of operating leakers during the concerned cycles and the structural integrity was adequate, the fuel was classified as intact or undamaged. When operating records indicated a fuel leaker, an additional inspection by ultrasonic testing of all the fuel in the concerned cycle was performed to determine the fuel leakers. If the examination results indicated that the fuel has cladding cracks, it was classified as damaged fuel without considering if it was a gross breach or a hairline crack. Additionally, it was confirmed that the water chemistry specifications for spent fuel pool has been fulfilled. Finally, a visual inspection before dry cask storage was performed and foreign particles were eliminated or characterized. These characterized particles were analyzed to assure the fuel-specific and system-related functions. No defects or missing of structural members have been observed. Spent fuels classified as damaged, has been stored with a special canister and located in special positions in the container. Therefore, considering final classification of the fuel assemblies, the final loading plan was defined and the fuels stored. (authors)