were taken out of the reactor and placed in the facility's cooling pond. The fuel rods have since been removed. At the 2.05 MW Ashford A power station Kent, UK, cooling water for the oil-fired engines was obtained from, and returned to, cooling water ponds. The principal cooling mechanism in the ponds was by convection from the water surface. At the 89 MW Back o’ the’ Bank power station in Bolton UK the cooling water was cooled in 4 spray ponds. The small size of the spray droplets improved the heat transfer, increased evaporation, and led to more effective cooling. Each cooling pond had a capacity of 0.75 million gallons per hour (0.95 m3/s). Make up water was abstracted from the nearby River Tonge. In about 1950 a hyperbolic reinforced concrete cooling tower was built with a capacity of 2.5 million gallons per hour (3.15 m3/s), with cooling range of 15 °F (8.3 °C). However, there were complaints that operation of the cooling tower let to problems with ice in cold weather as water vapour from the tower froze as fine particles. In 1963 the UK’s Central Electricity Generating Board (CEGB) was researching the possibility of using warmed cooling water from power stations to support fish-farming both for recreational use and for food. At Grove Road power station in London water was cooled in wooden natural draft cooling towers and fell into cooling water ponds. The CEGB introduced carp (Cyprinus carpio), grass carp, silver carp and Tilapia into the cooling water ponds; the fish grew rapidly in the warm water (up to 27 °C). See also Pond Solar pond (thermal energy collector) Deep lake water cooling References Cooling technology Ponds Water pollution