Despite an exhaustive search of its Humboldt Bay Power Plant near Eureka in northern California, segments of a spent nuclear fuel rod remain missing, Pacific Gas and Electric Co., says.
Plant personnel have completed the physical search of the most likely locations and all easily accessible spaces in the plant's used fuel storage pool, but the segments have not yet been found, the utility says. The pieces of the fuel rod were reported missing in June.
"Further, the review of plant records, nuclear material shipping records, and interviews with former plant personnel have not definitively identified the location of the fuel segments," PG&E says.
But the company says it still thinks the radioactive waste is "either safely stored in the used fuel pool, or were shipped to a facility licensed to accept radioactive material, no more recently than 1986."
When the material was reported missing, there was conflicting documentation regarding the used fuel segments, the utility says. "The plant's records indicate that the segments were either stored in the used fuel pool in 1968, or had been shipped offsite in 1969," it says.
Where are they now? "The highest probability is that the fuel segments are in an area of the [used fuel] pool that is not readily accessible, and will be located during a more detailed search of these locations. The second highest probability is that the fuel segments were shipped offsite to one of three appropriately controlled and restricted facilities licensed for analysis, storage or reprocessing of spent nuclear fuel. The third and most remote possibility is that the fuel segments were unintentionally included in a shipment to one of three licensed, monitored, and restricted, radioactive waste disposal facilities," PG&E says.
"No evidence has been uncovered to support the possibility of theft or diversion of the three fuel segments," the company says. "Due to the high radioactivity of this used fuel, to be handled safely the segments would have to be encased in a heavy, shielded container that would have to be moved with special handling equipment designed for this purpose, precluding an abrupt loss. This could not have occurred casually without plant staff or security personnel observing the movement.'
PG&E says it's still going over old paperwork and will continue its physical hunt for the material, "as expeditiously as it is practical and safe to do. However, it is possible that a complete search may not be concluded until the 390 used fuel assemblies, along with other components, are removed from the pool, as part of the plant decommissioning process currently set for 2009."