Nuclear energy is a clean, zero-emission energy source. Fission, the process of splitting uranium atoms to produce energy, is how it generates power. Without the toxic byproducts created by fossil fuels, the heat released by fission is used to create steam, which powers a turbine to generate electricity. Because of its high energy density and internalization of health and environmental costs, nuclear energy has a strong competitive position in terms of sustainable development. Nuclear energy has a number of sustainability advantages over other options, which explains its expanded role in practically all significant studies that detail viable pathways to long-term energy supply.