The invention relates to a steam power plant (1) having a bypass pipeline (12) which connects the fresh steam line (5) flow to the exhaust steam line (6), wherein a bypass steam desuperheater (20) is disposed in the bypass pipeline (12). In the event of an emergency stop, in the event of startup, or in the event of shutdown, the bypass steam desuperheater cools the steam flowing into the bypass pipeline (12), whereby cheaper materials can be used for the bypass pipeline (12).