An improved steam generator having an auxiliary recirculation path in its secondary side is disclosed herein, as well as an improved method for mixing wet lay-up chemicals therein. The invention is particularly applicable to nuclear steam generators of the type including a secondary shell that contains a quantity of water, a bundle of heat exchange tubes, and a tube wrapper that concentrically surrounds the tube bundle for defining a downcomer path. The auxiliary recirculation path allows the water present within the tube wrapper to circulate through the downcomer path when the water level within the secondary shell is lowered below the upper edge of the tube wrapper during maintenance operations. The auxiliary flowpath, when used in combination with nitrogen sparging, allows wet layup chemicals injected into the downcomer path of the generator to be rapidly and uniformly mixed throughout the entire water inventory in the secondary shell, thereby minimizing generator downtime and radiation exposure to maintenance personnel.