Abstract: In some operating states, supplemental additional sealing steam must be fed to the sealing-steam system of a steam turbine. The feeding of supplemental sealing steam from the live-steam line involves considerable problems. According to the invention, therefore, the sealing-steam system is connected via a feeder line to a bleed point of the superheater of the boiler, so that the temperature of the supplemental sealing steam is well below the live-steam data and, in particular, is compatible with the material temperature in the region of the high-pressure shaft seal.