<P> During the process of nuclear power generation, large volumes of water are used . The uranium fuel inside reactors undergoes induced nuclear fission which releases great amounts of energy that is used to heat water . The water turns into steam and rotates a turbine, creating electricity . Nuclear plants must collect around 600 gallons / MWh for this process, so the plants are built near bodies of water . </P> <P> A 2011 study by the National Renewable Energy Laboratory found that nuclear plants with cooling towers consumed 672 gal / MWhr . The water consumption intensity for nuclear was similar to that for coal electricity (687 gal / MWhr), lower than the consumption rates for concentrating solar power (865 gal / MWhr for CSP trough, 786 gal / MWhr for CSP tower), and higher than that of electricity generated by natural gas (198 gal / MWhr). </P> <P> When intaking water for cooling, nuclear plants, like all thermal power plants including coal, geothermal and biomass power plants, use special structures . Water is often drawn through screens to minimise to entry of debris . The problem is that many aquatic organisms are trapped and killed against the screens, through a process known as impingement . Aquatic organisms small enough to pass through the screens are subject to toxic stress in a process known as entrainment . Billions of marine organisms, such as fish, seals, shellfish, and turtles, essential to the food chain, are sucked into the cooling systems and destroyed . </P> <P> Many stages of the nuclear fuel chain--mining, milling, transport, fuel fabrication, enrichment, reactor construction, decommissioning and waste management--use fossil fuels, or involve changes to land use, and hence emit carbon dioxide and conventional pollutants . Nuclear energy contributes a very small amount of emissions into the atmosphere which can cause many environmental problems such as global warming . Uranium is not burned in a nuclear power plant as coal is so there are no emissions from it . All of the waste that comes from the fission of uranium stays in the plant and is therefore able to be disposed of in a safe way in which the uranium is kept out of the environment . "About 73 percent of emissions - free electricity in the United States comes from nuclear plants ." Nuclear energy produces far less carbon dioxide than coal, 9 grams per kilowatt hour compared with 790--1017 grams per kilowatt hour for coal . Also, nuclear energy produces the same amount if not less greenhouse gasses than renewable resources . Like all energy sources, various life cycle analysis (LCA) studies have led to a range of estimates on the median value for nuclear power, with most comparisons of carbon dioxide emissions show nuclear power as comparable to renewable energy sources . </P>

Speech on effects and control measures of nuclear power