Nuclear Fusion 1 of 24 Boardworks Ltd 2011
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How do we get energy from atoms? 3 of 24 Boardworks Ltd 2011 Energy is produced from atoms in power stations using the process of nuclear fission. Fission involves splitting atomic nuclei, releasing some of the enormous energy they contain. Energy can also be released by joining two small nuclei together to form a larger one in a process called nuclear fusion. nucleus electrons Fusion involves bringing two hydrogen atoms close enough together to make them fuse to form helium.
What is nuclear fusion? 4 of 24 Boardworks Ltd 2011 Nuclear fusion is the process that powers the Sun and other stars. In this process, small nuclei join together to form larger nuclei and energy is released. In the Sun s core, at temperatures of 15 million C, hydrogen nuclei fuse to form helium nuclei and release vast amounts of energy. A worldwide research programme is being carried out to find ways in which nuclear fusion could be harnessed on Earth as a clean and plentiful source of energy.
What happens in nuclear fusion? 5 of 24 Boardworks Ltd 2011
What are the conditions for nuclear fusion? 6 of 24 Boardworks Ltd 2011 In nuclear fusion, small nuclei fuse together to form larger nuclei and energy is released. + + + + 1 + H + deuterium tritium fusion helium neutron 2 H 3 1 4 H 2 n Nuclear fusion happens all the time in stars at very high pressures and temperatures. These conditions overcome repulsive forces between the nuclei and force them together. Scientists have found it difficult to create the extreme conditions needed to carry out nuclear fusion on Earth. 1 0
Fusion true or false? 7 of 24 Boardworks Ltd 2011
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Why is fusion so difficult? 9 of 24 Boardworks Ltd 2011
10 of 24 Boardworks Ltd 2011 Fusion in stars In a star like our Sun, fusion reactions happen easily. Because the Sun is very large, its gravity is very powerful and provides the pressure and temperature required for sustained fusion. gravity pressure On Earth, scientists need to recreate the pressure and temperature required in other ways, e.g. using magnetic fields. Creating and safely containing such high temperature and pressure environments is very difficult, and also very expensive.
What does a fusion reactor look like? 11 of 24 Boardworks Ltd 2011 The largest nuclear fusion experimental reactor is JET (Joint European Torus) in Culham, Oxfordshire. Fusion on Earth requires temperatures about six times hotter than the Sun s core. This vessel uses a magnetic field to trap super-hot hydrogen, which has changed from a gas into a high-energy plasma. The reactor is most efficient as a doughnut shape.
12 of 24 Boardworks Ltd 2011 How will a fusion power station work? In a fusion power station, the hydrogen plasma will be squeezed to produce helium and high energy neutrons. The energy of the neutrons will then be transferred by a water cooling loop to a heat exchanger to make steam. heat exchanger turbines plasma generator Then, like fossil fuel and fission power stations, the steam will drive turbines to produce electricity. It is hoped that the first fusion power station will be ready and working by about 2045.
Successful fusion reactions on Earth 13 of 24 Boardworks Ltd 2011 Fusion has been carried out successfully on earth since the 1950s. Hydrogen bombs (H-bombs) use the fission of uranium to heat the hydrogen to the temperatures needed for it to undergo fusion. There are many technical barriers to overcome, however, if fusion is to be used to as an energy source in the future.
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Nuclear fusion in the future 15 of 24 Boardworks Ltd 2011 Could nuclear fusion help solve energy problems on Earth?
16 of 24 Boardworks Ltd 2011 Why use nuclear fusion? There are many advantages to using fusion energy: Abundant fuels Deuterium can be extracted from water and tritium is made from lithium, which is readily available. Small amounts of fuel 10 grams of deuterium and 15 grams of tritium could produce enough energy for the lifetime of an average person in an industrialized country. Clean No greenhouse or other polluting gases are made. Safe No need to keep chain reactions under control. Less radioactive waste The products of nuclear fusion are not radioactive, although the reactor walls will absorb neutrons and become radioactive. No weapons material produced The products are not suitable for making nuclear weapons.
Pros and cons of using nuclear fusion 17 of 24 Boardworks Ltd 2011
Cold fusion 18 of 24 Boardworks Ltd 2011
Validating scientific discoveries 19 of 24 Boardworks Ltd 2011
Fusion research 20 of 24 Boardworks Ltd 2011
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Glossary 22 of 24 Boardworks Ltd 2011
Comparing nuclear fission and fusion 23 of 24 Boardworks Ltd 2011
Multiple-choice quiz 24 of 24 Boardworks Ltd 2011