αβγ decay
Decay Series
Chain Reaction
Nuclear Energy
Nuclear reactors

Fusion is where two light nuclei collide and coallesce, releasing energy.

The energy released from a nucleus far exceeds the energy released when atoms combine chemically.

Fusion happens successfully in the sun all the time.

The safe disposal of radioactive waste is a major concern.

A great deal of radioactive waste is repossessed for other uses.

Sellafield is the nearest nuclear waste reprocessing facility to Ireland.

The strong nuclear forces that bind the neutrons and protons together in the nucleus are far greater than the electrical forces that bind electrons to a nucleus. Energy derived from chemical processes is small because it involves only electron movement in the outer reaches of atoms. Energy derived from nuclear processes is far greater. This is because the binding energy of a nucleus is a measure of how tightly its neutrons and protons are held together by the nuclear forces.
The most tightly bound nuclei are found in the middle of the periodic table. Therefore if two light nuclei coalesce to form a heavier nucleus, or if a heavy nucleus splits into two lighter ones, the outcome is a more tightly bound nucleus and energy will be released.

How much energy?
Several MeV of energy are released in a fusion reaction and about 200 MeV in a fission reaction. A fission reaction releases about 10 million times as much energy as a chemical reaction.

How is nuclear energy obtained?
Nuclear power stations emit few of the gases associated with acid rain and they do not contribute to the greenhouse effect The use of nuclear power reduces the need to burn vast amounts of coal. However, nuclear power is not without its environmental impact. The main issue faced by the nuclear industry is the disposal of radioactive waste.

Nuclear Waste
The main environmental issue faced by the nuclear industry is the safe disposal and storage of radioactive waste. Each year a nuclear power station produces around 100 cubic meters of solid radioactive waste. Most of this waste is only slightly radioactive and can be dealt with easily. High-level nuclear waste is harder to dispose of and most of it is stored underground. This waste is contained within multi-layered metal and concrete vessels. Safety standards are extremely high in regard to the disposal of nuclear waste.

Classification of Waste
Radioactive waste can vary enormously in the amount of radiation that it is giving out, and so it is categorised into low-level (84%), intermediate-level (14%), and high-level waste (2%).

High-level waste is concentrated waste that is produced when nuclear fuel is reprocessed. Even though it represents only about 2% of the total volume of waste, it contains about 99% of the radioactivity produced. Most high-level waste is turned into glass blocks. This makes it easier to store safely. High-level waste is initially in the form of a liquid, which is hot and very radioactive. In the UK it is stored initially at Sellafield in stainless steel tanks cooled by cold water. Then a process called vitrification drives the water from the waste, and turns it into glass blocks, which will be stored in deep underground containers.

Intermediate-level waste includes items such as reactor components, cladding from fuel rods, effluent from treatment plants. Intermediatelevel waste is potentially dangerous. This waste is then put inside stainless steel drums. At present much of this sort of waste is stored at Sellafield (Cumbria, England), but will eventually be stored in a purpose-built repository cut into hard rock deep underground.

Low-level waste includes protective clothing and air filters that might be contaminated with traces of radioactive materials. Most low-level waste is packed into steel drums and stored in purpose-built concrete containers.