Inside the reactor is fuel made of uranium The reactor splits uranium atoms apart This process is called fission The reaction creates heat Water flows past the heat source It boils and turns to steam Steam then powers the whole ship The nuclear reactor works for years without refueling The limiting factor is the crew They need food and other supplies If a nuclear sub did not need a crew it could stay underwater for 25 years An Alternative Energy Source Today most of the world’s energy comes from fossil fuels These are made up of the remains of prehistoric plants and animals These fuels are USS Nautilus The world’s first nuclear submarine was the USS Nautilus The US Navy launched it on January 21 1954 The sub beat speed and distance records It was the first to cross under the icy North Pole Researchers learned a lot from it They soon built even better ships The Nautilus was declared a national historical landmark It later became a museum Visitors can tour it in Groton Connecticut 6
Coal is one of the most widely used fossil fuels commonly found underground Burning them releases energy Major fossil fuels include oil coal and natural gas Gasoline powers most of the cars now on the road It is made from oil 7
Fossil fuels have important downsides There is only a limited amount of them available Someday they will run out They also harm the environment Fossil fuels are burned to produce energy The burning process releases greenhouse gases These can lead to climate change Nuclear energy lacks these downsides It is one of many alternatives to fossil fuels The Fuel of Tomorrow In submarines nuclear reactors provide energy to move the sub On land reactors generate electricity Since the 1950s power companies have used them as a source of clean energy However nuclear energy also has downsides Nuclear reactions can be dangerous if they get out of control These accidents are very rare Only three major ones have happened in the history of nuclear power Waste products are another downside Reactors create waste that remains dangerous for a long time It stays radioactive for thousands of years 8
Nuclear power plants often have large cooling towers that are much larger than the actual reactor found in the smaller rounded structure 9
