§ Mr. Andrew F. Bennettasked the Secretary of State for Energy if he will indicate the extent of leakage of all types from the British Nuclear Fuels concrete storage silos at Sellafield; and if he will make a statement.
§ Mr. GoodladI am advised by British Nuclear Fuels plc that there are two concrete silos, B41 and B38, located at Sellafield, containing solid wastes arising from the reprocessing of irradiated fuel. B41 contains approximately 5,000 cubic metres of solid waste retained 355W in a dry environment to which no further additions have been made since 1964. Environmental and structural conditions are routinely monitored and demonstrate a completely stable situation with no problems relating to aerial or liquid discharges.
B38 contains approximately 9,000 cubic metres of solid waste retained in water filled compartments. Localised ground contamination found in 1970 during B38 phase II construction was attributed to a below-ground leak from one of the compartments of phase I. Measurements demonstrated that the activity released was firmly held in the clay sub-strata and did not extend beyond three to four metres from source. Group activity continues to be stable, with no further migration of activity, as evidenced by frequent routine monitoring and groud surveys, both in the immediate vicinity of the silo and elsewhere within the site boundaries.
Silo water level measurements have indicated that there have been no further leakages. This is attibuted to the leak path being blocked by the particulate products of magnesium corrosion, a natural process where Magnox fuel cladding material is stored under water.
Subsequent phases of B38 silo construction have utilised different design concepts, allowing for double containment, inter-space leak detection, and return of any leakage to silo. Cooling and recirculation systems were also installed in later compartments to control reaction rates and maintain low temperatures. No further leakages have occurred.
§ Mr. Andrew F. Bennettasked the Secretary of State for Energy if he is satisfied with current storage arrangements for spent Magnox fuel at Sellafield; and if he will make a statement.
§ Mr. GoodladYes. I am advised by British Nuclear Fuels plc that the new fuel handling plant is being commissioned, that receipts of irradiated fuel from Magnox stations are now received there prior to reprocessing, and that excellent storage conditions prevail.
The inventory of Magnox fuel received prior to commissioning of the fuel handling plant is held in one of the older Sellafield storage ponds and work is in hand to have this fuel reprocessed so that the pond can be prepared for eventual decommissioning.