Nuclear Power

Did you know that there have been 20 nuclear power plants in the UK? If you live near the coast, there could be one near you! Nuclear power plants are typically built near the sea because they need access to water for cooling fluid. Only six of these power plants are currently in operation – five in England, and one in Scotland. Despite nuclear power's bad rep, they're excellent sources of electricity and provide over 60,000 jobs. 

Nuclear Power Nuclear Power

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    Interested to know more about nuclear power? What are the advantages and what are the disadvantages? Direct your attention to this article!

    Nuclear Energy and Power Plants

    Let's begin by learning the definition of nuclear energy.

    Nuclear energy is the energy stored in the nucleus of an atom.

    The larger the atom, the more nuclear energy it has. To access this energy, atoms need to be split. This is known as fission. Nuclear energy is unique – the energy density of nuclear fuel is approximately 2 million times greater than any other chemical!

    Energy density is the amount of energy stored in a given system or volume.

    Nuclear Power

    So, what is nuclear power?

    Nuclear power is electricity generated using nuclear reactions.

    Today, over 400 nuclear power plants around the world produce 400 GW (gigawatts) of electricity – enough to power 400 million households for the year!

    Nuclear Power Plant: Explanation and Diagram

    Before we learn how a nuclear power plant works, let's recap the concept of radioactive decay.

    All elements have the same number of positively charged protons and negatively charged electrons. But they may have different numbers of neutrons.

    Isotopes are forms of the same element but with different numbers of neutrons.

    Sometimes, these isotopes are unstable. These atoms will decay by releasing fission products (a package of subatomic particles) and a burst of ionising radiation to change into a smaller, more stable element.

    Isotopes that undergo more than one step of decay are the most useful for generating nuclear power.

    Fission Power Plants

    A nuclear power plant (also known as a nuclear reactor) is a series of machines that control nuclear fission to produce electricity. Most power plants use uranium as a fuel – in particular, the isotope uranium-235.

    The uranium-235 isotope is rare – making up less than 1% of the world's uranium.

    Alternatively, an isotope of plutonium is used (plutonium-239).

    Atoms of the nuclear fuel are forced to break apart. As they split, the atoms release fission products. These induce nearby atoms to split, starting a chain reaction.

    As the atoms split apart, they release energy in the form of heat:

    • The heat is used to convert water into steam.

    • The steam drives turbines (converting heat → kinetic energy)

    • The movement of the turbines drives a generator (converting kinetic energy → electrical energy)

    To stop the chain reactions from getting out of control, nuclear power plants contain boron control rods. These rods absorb neutrons, stopping them from splitting more uranium atoms. Raising the rods speeds up the rate of decay, while lowering them slows it down.

    Uranium Mining Techniques

    How is uranium extracted from Earth's crust?

    • Open pit mining: drilling and blasting create a large hole in the ground, exposing the ore. Then, the ore is mined using blasting and excavation techniques.

    • Underground mining: underground ores are extracted using blasting, pneumatic drilling, picks, and shovels. This mining technique exposes workers to harmful radon gas.

    • In-situ leaching: chemicals are used to separate the uranium from surrounding rock. The chemicals are mostly sulfuric acid or sodium bicarbonate. In-situ leaching is the predominant method of uranium mining.

    Thorium Reactors

    Thorium-based nuclear reactors have been suggested as an alternative to uranium-based reactors. The reactors would be molten salt reactors, with the thorium remaining as a liquid fuel; safer than uranium-based reactors. Thorium reactors would generate less radioactive waste. Furthermore, thorium is approximately three times more abundant than uranium.

    However, molten salt reactors are difficult and highly expensive to develop. A commercial thorium reactor is decades away.

    Complications of Nuclear Energy Density

    Earlier, we learned that nuclear fuels have an enormous energy density – far greater than any other fuel.

    FuelEnergy Density (MJ/kg)
    Natural Gas53.5

    If there's so much energy in nuclear fuel, why don't we have more electricity than we could ever need? Well, we need to consider a few factors:

    • Enrichment: only a small fraction of mined material is used in power plants

    • Fuel consumption: only 6% of the fuel's energy is extracted in traditional power plants

    • Thermal efficiency: nuclear power plants can only convert 33% of heat to electricity

    Despite these reductions in effective energy density, nuclear fission remains an effective and useful tool for generating electricity.

    Fusion Power Plants

    Nuclear fusion occurs when the nuclei of two light elements are forced together to form one nucleus of a heavier element. Nuclear fusion takes place in the Sun, providing so much energy that it can heat Earth from millions of kilometres away.

    Fusion reactions are estimated to produce four times as much energy as fission reactions, without radioactive waste! Thus, fusion power plants could be groundbreaking – but scientists are struggling to develop suitable technology. Nuclear fusion requires temperatures of over 100,000,000ºC; difficult to create on Earth.

    Researchers are focusing on hydrogen fusion reactions, using heavy isotopes deuterium and tritium. When combined, they produce helium nuclei. The process releases large amounts of energy, and occurs at lower temperatures than other elements.

    Toroidal Reactors

    Some experimental fusion power plants use a machine called a tokamak. It confines a plasma using a magnetic field, creating a doughnut shape called a torus.

    A plasma is a medium filled with positive ions and electrons. It acts like a gas, conducting electricity.

    Plasmas are often called 'the fourth state of matter'.

    Magnetic coils generate an intense 'toroidal field'. In the centre of the torus, another magnet creates a 'poloidal field'. These magnetic fields work together, confining particles in the plasma and creating the conditions needed for nuclear fusion.

    Laser Fusion

    During laser fusion, deuterium and tritium are added to a blast chamber and compressed to high densities using an intense laser beam. The high density and heat from compression provides the conditions required for nuclear fusion.

    In August 2021, Californian scientists used laser fusion to generate over 10 quadrillion watts of fusion power. That's over 700 times the electrical capacity of the entire US power grid!

    A disadvantage of laser fusion techniques is that lasers are relatively inefficient at converting electrical energy into light energy. Plus, some laser light is reflected or scattered away.

    Countries that Use Nuclear Power

    Over 30 countries use nuclear power to generate electricity. Who are the top ten biggest producers?

    PositionCountryElectricity Generated (MW)
    1United States96553
    5South Korea23091
    9United Kingdom8923

    Although the US produces the most electricity using nuclear power, France produces the greatest proportion of their electricity from nuclear power (roughly 70%).

    Nuclear Power in the UK

    The UK is home to six operational nuclear power plants:

    • Dungeness B, Kent
    • Hartlepool, County Durham
    • Heysham 1, Lancashire
    • Heysham 2, Lancashire
    • Sizewell B, Suffolk
    • Torness, East Lothian

    In 2022, nuclear power stations Hinkley Point B and Hunterston B were shut down.

    In 2021, nuclear power generated 14.8% of the country's electricity.

    Advantages of Nuclear Power

    What gives nuclear power an edge over fossil fuels?

    Carbon-freeProducing electricity using nuclear power doesn't produce any greenhouse gas emissions. In fact, the use of nuclear power is estimated to save 555 million tons of carbon emissions every year!
    Clean Energy SourceUsing nuclear power doesn't produce air pollution that can affect living organisms and the environment.
    Energy DensityNuclear fission power plants produce almost 8000 times as much energy as a fossil fuel power plant.
    Low Operational CostsOnce constructed, nuclear power stations don't cost much money to run. Thus, nuclear power presents a minimal risk of cost inflation.
    ReliabilityNuclear power can be relied upon to produce the same amount of energy, regardless of weather, season, or time of day.

    Disadvantages of Nuclear Power

    It's important to recognise that no energy resource is perfect. So, what are the disadvantages of nuclear power?

    Non-renewableUranium and plutonium are finite resources, which will eventually be depleted. We cannot continue to use fission power plants forever.
    Initial CostIt's incredibly expensive to build a nuclear power station – each one costs billions of dollars. This is because each power station requires special facilities to safely store waste.
    Destructive MiningMining uranium for fuel is a highly destructive process. It destroys habitats, causes pollution, and impacts natural communities.
    Radioactive WasteThe most well-known disadvantage of nuclear power stations is radioactive waste. It can be hazardous to health for thousands of years, so must be stored in specially constructed facilities until it is no longer harmful. If the power plant experiences an accident, there is a risk of radioactive material being released into the environment.

    The notorious Chernobyl accident took place in April 1986. Poorly designed control rods, operated by inadequately trained workers, led to a power surge, which caused an explosion. Two workers died immediately, and a further 28 died in the following weeks from acute radiation syndrome. Approximately 350,000 people were relocated from the nearby area.

    Nuclear Power abandoned building chernobyl disadvantages of nuclear power StudySmarterFig. 3 – An abandoned building near the site of the Chernobyl accident. Source:

    I hope that this article has explained nuclear power for you. Remember that it is electricity generated using nuclear reactions. Nuclear power produces vast amounts of electricity without carbon emissions or pollutants, but does create radioactive waste that must be stored carefully.

    Nuclear Power - Key takeaways

    • As uranium atoms split, they release fission products. These induce nearby uranium atoms to split, causing a chain reaction and releasing energy.
    • Nuclear fusion research is focusing on hydrogen, which requires a lower temperature and releases more energy than other atoms.
    • Over 30 countries use nuclear power to generate electricity. In the UK, there are six operational power plants, generating 14.8% of the country's electricity.
    • Advantages of nuclear power include reliability, a lack of carbon emissions or pollutants, high energy density, and low operational costs.
    • Disadvantages of nuclear power include destructive mining for a finite resource, high construction costs, and hazardous radioactive waste.

    1. Ashley Micks, Thorium Reactors: An Improvement Over Uranium?, Stanford University, 2013

    2. Daniel Higginbotham, Getting a graduate job in nuclear energy, Prospects, 2022

    3. Dr Nick Touran, Computing the energy density of nuclear fuel,, 2022

    4. Jeff Tollefson, US achieves laser-fusion record: what it means for nuclear-weapons research, Nature, 2021

    5. Kim Rutledge, Nuclear Energy, National Geographic, 2022

    6. Matteo Barbarino, What is Nuclear Fusion?, IAEA Department of Nuclear Sciences and Applications, 2022

    7. Olivia Hudson, Advantages and Disadvantages of Nuclear Power Stations, AZO Clean Tech, 2022

    8. Power Reactor Information System, Nuclear Share of Electricity Generation in 2021, International Atomic Energy Agency, 2022

    9., What is nuclear energy?, 2022

    10. World Nuclear Association, Chernobyl Accident 1986, 2022

    11. World Nuclear Association, Nuclear Power in France, 2022

    12. World Nuclear Association, Nuclear Power in the World Today, 2022

    Frequently Asked Questions about Nuclear Power

    Is nuclear power a clean energy source?

    Nuclear power is a clean energy source; it does not produce any greenhouse gases or pollutants.

    How is energy generated from nuclear power?

    In a nuclear power station, uranium fuel undergoes a controlled chain reaction, which releases energy in the form of heat. The heat is used to convert water into steam, which drives turbines, which power a generator.

    How many nuclear power plants are there in the UK?

    There are six operational nuclear power plants in the UK.

    How does nuclear power work?

    Nuclear power uses the nuclear energy stored inside atoms to generate electricity.

    Is nuclear power renewable?

    Nuclear power is not renewable. The fuels used (uranium or plutonium) are finite resources.

    Test your knowledge with multiple choice flashcards

    If fusion is first in terms of energy density, what category is known to be the least energy-dense?

    Metals used in cold fusion include...

    What element shortage could hydrogen fusion on Earth "fix" in the near future?


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