Academic Review 2024

53 ACADEMIC REVIEW 2024

“ Nuclear reactors are the most efficient energy producers on the market. ”

Nuclear fission physics Nuclear fission is the process of splitting one atom into two smaller elements and neutrons. This releases enormous amounts of energy and when controlled can be used to generate electricity in power plants. The most common elements used for fuel are Uranium-235 and Plutonium-239 (WNA, 2020). When uranium is split, two smaller elements are produced along with two or three neutrons. These neutrons can go on to split other uranium atoms which would then split even more atoms creating a chain reaction. In an uncontrolled environment, this reaction is exponential and quickly becomes a massive surge of energy creating an explosion. This is how first-generation atomic bombs worked. In nuclear power plants, however, the fission is controlled. Only one out of the three neutrons emitted causes another fission to occur, allowing for a continuous stable reaction. Nuclear reactors all work the same way. The energy released by the fission is absorbed by a coolant (usually water), which eventually turns into steam to drive turbines (WNA, 2022). The fundamental fuel is the uranium. It comes as small pellets of uranium oxide (UO2), reactors can have over 18 million arranged in fuel rods. The core of the reactor emits high amounts of radiation. This is why the entire reactor is surrounded by a thick wall to protect the workers from harmful radiation.

Nuclear reactors are the most efficient energy producers on the market. ‘A pellet contains as much energy as one tonne of coal’ (The Nuclear Energy Institute, 2020). Yet only about 15% of the UK’s electricity is generated from nuclear power plants of 6.5 GW total capacity (WNA, 2022). A typical 1-gigawatt reactor provides enough electricity for a city of one million people, about 8 billion kWh per year. It raises the question: why aren’t there more operational reactors in the world? Although the concept of high output of energy with no greenhouse gas emission seems great, there are disadvantages. One issue is the radioactive byproduct of the fission reaction. When U-235 is fissioned, the smaller elements produced have a large neutron number. This makes them highly unstable and likely to undergo beta decay. Some of the byproducts have a short half-life, however others can have half-lives of over 30 years, making them harmful for a very long time. If the waste is not managed correctly, it may pose a threat to people’s health and the environment. Another drawback of fission reactors is the risk of meltdowns. Fission is a chain-based reaction and if not controlled will exponentially grow to a huge explosion. The role of the control rods in the reactor is to absorb the extra neutrons and keep the reaction stable. All it takes is for one malfunction to blow the power station. This poses a threat to the workers and the local population. In the case of a meltdown, large amounts of radioactive dust are released contaminating the area surrounding the plant. The area affected can be very large.