Nuclear power station construction. Worker using welding machinery during the construction of part of a steam generator for a nuclear power plant. This is the steam generator's lower end. Steam generators are large structures (over 20 metres in height) used in pressurized water reactors (PWRs). The large round connectors (left) are where hot pressurized water enters, having been heated by the nuclear reactor. The heat from the pressurized water boils a separate volume of water into steam that rotates turbines to generate electricity. The pressurized water is recycled to the reactor to be heated again. Photographed at the Framatome ANP facility at Chalon/Saint Marcel, France.