[en] The cooling water system which would be needed for the proposed Sizewell B power station is described. The possible effects upon public safety, local fishing interests and the existing seabed are examined. Studies of the heat dispersion from outfalls, the location of offshore structures and the control of marine growth in the system are reported. Finally the essential service water system, the reserve ultimate heat sink, the discharge of liquid radioactive waste into the sea and the possible use of waste heat for agricultural and fish farming purposes are discussed. (U.K.)