A thermal power generation apparatus comprises a boiler (15) and multiple turbine sets for high, intermediate and lower steam pressure operation. Steam exhausted from the high pressure turbine (HP), and reduced in both pressure and temperature, is returned to a reheater (19) for reheating. The reheated steam is then passed to a intermediate pressure turbine (IP). It is desirable to control the temperature of steam entering the intermediate pressure turbine (IP). The invention provides a system for effecting temperature control of the reheater stream in a thermal power plant. The system includes a reheater conduit (10, 21) adapted to define at least a part of a reheat flow path for steam between an exhaust of a high pressure turbine system (HP) and an inlet of a reheater system (19). The system further includes an indirect water/steam heat exchanger (B) having a heat exchange portion within the reheat flow path and defining a water flow path means adapted to receive and circulate feed water. The feed water may be taken from take off points (A, D) in the primary feed water stream.