Abstract: The temporary fastening system for joining upper and lower shell casings of a turbine to one another for maintenance purposes includes a stud/nut tensioning system employed in lieu of the conventional studs and nuts. Once the turbine is opened up and the inner shell and rotor removed, the upper and lower shell casings are temporarily secured to one another using studs received in registering openings in the horizontal flanges of the upper and lower shell casings and retainer plates serving as a stop for the stud/nut tensioning system. The tensioning system is hydraulically operated and avoids torsional force on the temporary studs. Once measurements are made, the turbine is again reopened and reassembled using the initially removed bolts or a third set of bolts to secure the upper and lower shell casings to one another.