Nuclear power station construction. Workers with plans for the internal tubing of a steam generator for a nuclear power plant. Thousands of tubes will be inserted through holes in support plates (such as the one in the background). Steam generators are cylindrical structures (over 20 metres in height) used in pressurized water reactors (PWRs). Pressurized water, heated by the nuclear reactor, passes into the thin tubes that will be surrounded by water. The heat boils this water, forming steam that rotates turbines to generate electricity. The pressurized (radioactive) water is recycled to the reactor and reheated. Photographed at Framatome ANP's facility at Chalon/Saint Marcel, France.