Nuclear Physics

The second half of the nineteenth century saw an increase development in the application of nuclear physics in power generation and most infamously, nuclear weapons/bombings. In this phase of the tour, I will teach and show you the basic theory behind how nuclear reactions work, and the danger nuclear radiation poses to us and the environment.

Basic structure of an atom

Electron — These have a negative charge, negligible mass and orbits the nucleus

Nucleus — This is the collective name given to the centre mass containing protons and neutrons

Proton — These have a positive charge and a relative mass of 1

Neutron — These have no charge and a relative mass of 1

Atom Diagram

Nuclear Fission

Nuclear fission is the process whereby large, unstable atoms are 'split up' and as a result release large amounts of energy. The most common element used for this process is called uranium. They are labelled as 'unstable' because it does not have a strong enough binding force to hold the nucleus together. Put simply, it is like a large, fragile balloon – one touch of the balloon and it will explode.

In a similar way, the unstable atom is made to 'explode' by firing a neutron into the atom. As a result, the atom splits up into two new atoms, a number of neutrons, and a lot of energy. The energy released is millions of times more than the energy released through the combustion of petrol.

Shown on the right is a fission reaction of the element uranium. When a neutron is fired into the uranium atom, it splits into krypton and barium, releases 3 neutrons and a whole lot of energy.

By using the extra neutrons released in the nuclear fission and firing them into more unstable atoms, a chain reaction can be set up. This is the key principle behind nuclear power plants and nuclear bombs.

Nuclear fission reaction

Dangers of radiation

When unstable atoms naturally break down (decay) they release they release radioactive particles. There are three types of particles: alpha α, beta β and gamma γ. They are considered dangerous as they are able to ionise. They are able to change the stucture of atoms by knocking off or dragging electrons away from the atom.

In humans, animals and plants, this ionising effect alters the DNA code in cells causing cell mutation. Through this, the altered cells are reproduced through cell division which may then form cancerous growths. The corrupted code can also contribute to mutated limbs, organ functionality and death.

This radiation isn't only sourced from the site of a nuclear disaster. Poising can occur through contaminated water which then infects soil and hence food supplies. To add more to this potential problem, radioactive particles can stay hazardous for thousands of years.

Because of this danger, workers at nuclear power plants are specially trained and adhere to strict safety precautions. Additionally, power plants usually have emergency shutdown procedures which automatically initiate when problems arise.

Continue to the tour of the power plant

Deformed baby

[Left] Igor was born with no right arm and tiny legs
[Right] A mutated daisy similar to one found on Three Mile Island, USA