The radioactive sludge results from the reprocessing of fuel from Magnox reactors and is stored under water in silos that are now nearly full. The silos have to be emptied because the waste will outlive the building.
Emptying the silos will be limited by the technical difficulties of the task, the HSE says in a report on radioactive waste at Sellafield and the United Kingdom's nuclear power stations. According to the HSE, the waste is in various stages of corrosion and 'none of the silos was designed with recovery . . . in mind'.
BNFL has built a mechanical grab to handle solid material from later silos, but the waste in earlier compartments could prove more difficult. The HSE 'is concerned that recovery of this more severely corroded material will prove to be much more difficult, particularly since large miscellaneous items are also present'.
The HSE is happy, however, with other aspects of radioactive waste storage at Sellafield. It says: 'The level of BNFL expertise in dealing with radioactive waste was found to be very high . . .'