Steam turbine plant

A steam turbine plant comprising:

• a boiler configured to change water into steam;
• a high pressure turbine including a turbine or turbines connected to each other in series, and having a first inlet configured to supply the steam from the boiler, an extraction port located downstream of the first inlet, a second inlet configured to supply the steam extracted from the extraction port and located downstream of the extraction port, and an exhaust port located downstream of the second inlet, the high pressure turbine being configured to be driven by the steam supplied from the first and second inlets, and the steam from the first inlet and the steam from the second inlet being merged in the high pressure turbine and exhausted from the exhaust port;
• an extraction steam heater configured to heat the steam extracted from the extraction port and to supply the heated steam to the second inlet;
• a reheater configured to heat the steam exhausted from the exhaust port;
• and
• a reheat turbine configured to be driven by the steam from the reheater.