A single-loop nuclear power plant with a pressurized coolant, comprising a power generating unit and a throttling device having an impeller, which are interconnected by an outlet pipe and a feed pipe, and a steam turbine connected to the throttling device and to a condenser connected to the throttling device, which device is a throttling steam generator vertically divided into a vapour zone, a high pressure zone, and a low pressure zone by horizontal sealed partitions. The high pressure zone is connected to the the feed pipe and is connected to the low pressure zone by throttling nozzles provided in the partition between said zones, and the low pressure zone is connected to the vapour zone by a vertical pipe which passes through the the horizontal sealed partitions and the high pressure zone. The single-loop nuclear power plant is provided with an electric motor to rotate the impeller.