Abstract: A system for removing sludge from a sludge-bearing fluid flowing in a vertically oriented nuclear steam generator so that the sludge is not present therein in sufficient quantities to corrode components (e.g., heat transfer tubes) located in the steam generator. The system comprises a tube sheet having a plurality of apertures therethrough for receiving the ends of the heat transfer tubes so that the tubes are supported by the tube sheet. The tube sheet has a top surface thereon and also a recess formed in the top surface for separating and for collecting the sludge from the sludge-bearing fluid. The recess has a substantially frusto-conical wall generally converging at the bottom end of the recess for providing a settling basin for the sludge after the sludge is separated from the sludge-bearing fluid. A pipe extends from adjacent the bottom end of the recess to the exterior of the heat exchanger for transporting the sludge from the recess to the exterior of the heat exchanger.