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Uranium ore is extracted from the ground, milled, purified, and concentrated at the mine site into a fine powder known as yellowcake. This concentrate is then transported to specialist converters for the next stage of the cycle.

In its natural state, uranium contains only 0.7% of the active uranium isotope Uranium 235 which, by fission inside the nuclear reactor, releases the thermal energy necessary for electricity generation.

The ore concentrate is broken down and chemically converted to form a compound called uranium hexafluoride, a solid at room temperature. This is then transported in secure containers to the uranium enrichment plant.

Natural uranium is composed of two types of isotopes, namely U-235 and U-238. Only U-235 is capable of sustaining fission (or atom splitting). This is what creates the energy to run a nuclear power plant.

However, U-235 makes up less than 1% of natural uranium. For uranium to be usable as nuclear fuel, a higher concentration of U-235 is required. The enrichment process produces this higher concentration, typically between 3% and 4% U-235, by removing a large part of the U-238 (80% for enrichment to 3.5%).

There are two enrichment processes in large-scale commercial use, each of which uses uranium hexafluoride as feed. They are gaseous diffusion and gas centrifugation. The product of this stage of the nuclear fuel cycle is enriched uranium hexafluoride. This is reconverted to produce enriched uranium oxide.

Reactor fuel is generally in the form of ceramic pellets. They are formed from pressed uranium oxide, which is sintered at a high temperature (over 1400 degrees Celsius). The pellets are then encased in metal tubes, which are arranged into a fuel assembly ready for introduction into a reactor.

The generation process starts with the splitting of uranium atoms in a controlled way inside a reactor. This produces heat energy.

An atom consists of protons, neutrons and electrons. When the atom is split, two or three neutrons are thrown off at tremendous speed- about 10,000 miles per second.

The reactor's graphite core or moderator slows down these neutrons. This facilitates their interaction with other uranium atoms, resulting in another split. More heat energy and more neutrons are released, creating a "chain reaction".

The fissioning of uranium is used as a source of heat in a nuclear power station. It works in the same way that the burning of coal, gas or oil is used as a source of heat in a thermal power plant.

The core contains vertical channels for uranium fuel elements and control rods. These rods are generally made of boron steel. They absorb neutrons to allow the reactor to be started or shut down and to control its power level.

Either carbon dioxide or water is pumped through the channels. This cools the fuel and transfers the heat energy to boilers to produce steam. The steam is used to drive a turbine connected to a generator, which produces electricity.

Electrical power is generated at high voltage for distribution by transmission lines. After a series of voltage step-down processes, the electrical power is delivered to industry and private households.

The global population is increasingly reliant on electricity. Electricity cannot be stored, and therefore has to be supplied on demand. It is therefore essential that the electricity supply is met via a sustainable route which balances accessibility, acceptability and affordability.

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