Transshipment of spent fuel at San Onofre nuclear generating station

San Onofre nuclear generating station is a three-unit facility. Unit 1 is a 456-MW(electric) Westinghouse pressurized water reactor that went into commercial operation in 1968. The unit 1 spent-fuel pool is of limited capacity, holding a maximum of 216 assemblies. The unit 1 core contains 157 assemblies, of which 52 are discharged approximately every 2 yr. Units 2 and 3 are 1127-MW(electric) units that went on line in 1983 and 1984, respectively, each with additional spent-fuel storage capacity. Since the unit 1 spent-fuel pool was filled with fuel by every fourth refueling outage, the fuel was shipped to Morris, Illinois, in the past. However, this option is no longer open to Southern California Edison, and the 10-yr in-service inspection that requires the core to be completely off-loaded is to occur during the 1991 refueling outage. With the inventory of 146 assemblies from past outages and the added 52 assemblies from the 1989 refueling, no room would be available for a full-core off-load, or even any future refuelings. The immediate storage capacity of units 2 and 3 was sufficient for each to accept half of the fuel then stored in unit 1. The planned reracking of units 2 and 3, plus the potential of future fuel consolidation, made transshipment of fuel from unit 1 to units 2 and 3 a viable and cost-effective option. The success of the operation was attributed to effective preplanning, which resulted in the detailed procedure, a comprehensive training program including the dry runs, several innovations that evolved from the planning process and lessons learned, and dedicated crews from each organization