Mobile apparatuses move within contaminated fluid to create fluid flows against structures that remove and prevent contaminant deposition on structure surfaces immersed in the fluid. Unsettling flows in water may exceed approximately 2 m/s for radionuclide particles and solutes found in nuclear power plants. Mobile apparatuses include pressurized liquid from a pump or pressurized source that can be chemically and thermally treated to maximize deposition removal. When spraying the pressurized liquid to create the deposition-removing flow, mobile apparatuses may be self-propelled within the fluid about an entire surface to be cleaned. Mobile apparatuses include filters keyed to remove the contaminants moved into the coolant by the flow, and by taking in ambient fluid, enable such filtering of the ambient fluid along with a larger flow volume and propulsion. Propulsion and the pressurized liquid in turn enhance intake of ambient fluid.