What are the key learning points about nuclear fusion?
What are the steps involved in the The joining together of two smaller atomic nuclei to produce a larger nucleus. Radiation is released when this happens. Nuclear fusion happens in stars like our sun, and in hydrogen bombs. process?
Where does fusion occur naturally?
How close are scientists to achieving fusion on Earth?
The advantages and disadvantages of fusion for producing electricity.
What happens during nuclear fusion?
Fusion reactions naturally take place in stars such as our sun, where two hydrogen nuclei merge under extreme temperature and pressure to create a helium nucleus.
What are the arguments for and against nuclear fusion?
For nuclear fusion:
Nuclear fusion could solve the world’s energy needs because hydrogen and deuterium are widely available as the constituents of seawater and so are relatively cheap and nearly inexhaustible.
Fusion does not emit carbon dioxide or other The gases responsible for global warming - carbon dioxide, methane, nitrous oxide and CFCs (chlorofluorocarbons). into the atmosphere.
There is no radioactive waste with a fusion reaction, and the major by-product is helium, an inert (unreactive), non-toxic gas.
Fusing nuclei together in a controlled way releases four million times more energy per kg than a chemical reaction such as burning coal, oil or gas - this keeps transportation and mining costs low and reduces the associated hazards.
Nuclear fusion releases four times more energy per kg than a nuclear fission reaction.
Against nuclear fusion:
The technological difficulties of fusion reactors are difficult to overcome.
Temperatures approaching the temperature of the Sun (approximately 150,000,000 °C) are required for fusion to occur on Earth, and reaching this very high temperature and containing the reaction at it for a sufficiently long time is very difficult.
There are many difficulties to overcome before nuclear fusion provides electricity on a commercial scale and it may be another 50 years before that happens.
Nuclear fusion reactors will be expensive to build because of the technology required.
The system used to contain the nuclear fusion reaction will be expensive to operate because of the very high temperatures needed for the nuclei to fuse.
Nuclear fusion on Earth
Scientists believe that fusion can be achieved on Earth using the two heavy An isotope of an atom of an element that releases ionising radiation. Also called a radioisotope.of hydrogen, hydrogen-2 (deuterium) and hydrogen-3 (tritium).
This is commonly referred to as the D-T reaction.
When a nucleus of hydrogen-2 (deuterium) collides with a nucleus of hydrogen-3 (or tritium) a nucleus of helium-4 is created and a neutron is released.
\(_{1}^{2}\textrm{H} + _{1}^{3}\textrm{H} \rightarrow_{2}^{4}\textrm{He} + _{0}^{1}\textrm{n} +\textrm{energy}\)
Energy is released as electromagnetic radiation.
Nuclear fusion occurs when two nuclei fuse to form a new nucleus, a neutron and energy is released.
The nuclei of deuterium and tritium are fired into a plasma where extreme temperatures overcome their repulsion and forces them together.
Per kg of fuel, nuclear fusion releases four times more energy than nuclear fission.
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