Staff worked against the clock to supply cooling water to four of the 21 tanks, said to hold around 1,000 cubic metres of highly radioactive liquid waste.Details of the alert are given in the latest Sellafield site newsletter which says: “Cooling water was reinstated to the high-heat highly active storage tanks within two hours of the initial loss and to the remainder of the plant within eight hours... this is within the bounds of the plant safety case.”But Cumbrian anti-nuclear group Core has made the startling claim that “this is perilously close to the timescale of 10.5 hours catered for in the Sellafield site emergency plan”.