System and method for stress-relief of welds in heat exchanger tubes

Abstract

Both a system and method for simultaneously heat treating a plurality of heat exchanger tubes in the tubesheet of a steam generator are disclosed herein. The system generally comprises a plurality of heater probes receivable within the open ends of the tubes, each of which has a bladder means for detachably securing the probe within the tube, a plurality of hose-like probe guide assemblies positionable over the open ends of the tubes for guiding the heater probes into the tubes, and an end effector having a cup-shaped coupler connected to a robotic arm for delivering the probe guide assemblies over the open ends of different tubes. The ability of each of the heater probes to detachably mount itself into proper position within its respective heat exchanger tubes advantageously frees up the robotic arm so that it can quickly and sequentially install a number of probe guide assemblies and heater probes in different locations within the tubesheet. Because the probe guide assembly installation time is a relatively small part of the entire heat-treating operation of a single tube, the system and method of the invention allows a plurality of non-adjacent tubes to be substantially simultaneously heat treated, thereby advantageously shortening the total amount of time necessary to perform the heat-treatment maintenance operation.