Abstract: A system and method for detecting, and then specifically locating, a leaking tube or tubes from among a plurality of tubes which extend through a chamber and are accessible at their opposite ends from outside the chamber, such as, for example, cooling tubes of a steam condenser. The system includes a reservoir containing a supply of tracer fluid, a plurality of conduits forming a matrix which releases tracer fluid in a controllable manner into predetermined groups of tubes without interruption of the flow of normal process fluid through all of the tubes, and a detector for sampling process fluid normally flowing through the chamber for the presence of tracer fluid, the detection of tracer fluid being indicative of a leak and the capability of controllably releasing tracer fluid to the tubes permitting the localization of which specific tube is leaking.