Corrosion of steel piping and basin equipment was found to be the main cause of the deposition of a brown flocculent material on the floor and walls of the disassembly basin at R Pile. A combination of sodium dichromate and chloramine, the best of seven water treatments tested, reduced steel corrosion 50 per cent, zinc corrosion 80 per cent, and met the standards for control of turbidity and bacteria in the water of the basin.