A replacement tube plug for sealing the threaded junction between a tube plug and a bore in a plugsheet, the tube plug including a body part having proximal and distal ends, an outer threaded surface, a central bore open at the proximal end and at least one branch bore extending from and in fluid communication with the central bore and extending radially to the outer surface of the body part, and a method for delivering fluid sealant via the central and branches to the threaded junction of the tube plug and the plugsheet.