What is Nuclear Science?

Nuclear science is the study of the atomic world.

Penetration of radiation - a guide.

Everything is made of atoms. We are entirely composed of them, as is everything that surrounds us. Learning what atoms do and what happens when they combine is of critical importance. It has a constant effect on our lives. If we know how atoms get together, or can be best combined with others, new, more efficient materials and drugs can be developed through 'molecular engineering' and 'rational drug design'.

Investigation of matter at the atomic level is one of the most important fields of scientific research.


Radioactive decay

Radioactive decay is the spontaneous radioactive disintegration of an atomic nucleus resulting in the release of energy in the form of particles (for example, alpha or beta) or gamma radiation, or a combination of these.

Radioactive decay is one process through which unstable atoms can become more stable.

Penetration of radiation

In alpha decay, a positively-charged particle is emitted from the nucleus of an atom. An alpha particle consists of two protons and two neutrons (a helium-4 nucleus). Although alpha particles are normally highly energetic, they travel only a few centimetres in air and are stopped by a sheet of paper or the outer layer of dead skin.

Beta decay

In beta decay, a particle is emitted from the nucleus of an atom. A beta particle is an electron with either negative or positive electric charge. Beta particles may travel metres in air and several millimetres into the human body. Most beta particles may be stopped by a small thickness of a light material such as aluminium or plastic.

Gamma decay

Gamma decay occurs because the nucleus of an atom is at too high an energy state. The nucleus falls down to a lower energy state, emitting a high energy photon known as a gamma particle in the process. Gamma particles travel in a wave-like pattern at the speed of light. They can only be stopped by a dense material such as lead, steel, concrete or several metres of water.


Fission vs fusion

When atoms split apart or join together, energy is released. This is nuclear fission and nuclear fusion.

Nuclear fission

An atom's nucleus can be split apart. When this is done, a tremendous amount of energy is released in the form of both heat and light. The word fission means to split apart. Inside a nuclear reactor, such as OPAL, uranium atoms are split apart in a controlled chain reaction.

In a chain reaction, neutrons released by the splitting of the atom go off and strike other uranium atoms, splitting those and releasing another lot of neutrons to continue striking more uranium atoms. In nuclear reactors, design features and control rods are used to regulate the splitting so it does not go too fast. If the reaction is not controlled and the fuel is almost pure uranium-235 or plutonium, you could have an atomic bomb. These conditions are not present in a nuclear reactor.


Nuclear fusion

Fusion is when smaller nuclei join together to make a large nucleus. The sun is powered by nuclear fusion of hydrogen atoms into helium atoms. This gives off heat, light and other radiation.

Scientists have been working on controlling nuclear fusion for a long time, trying to make a fusion reactor to produce electricity. To date, prototype fusion reactors have consumed more energy than they have produced, but scientists believe that the future of fusion research is promising.

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