WHAT IS NUCLEAR POWER?

Nuclear power is an alternative power source that uses the nuclear fission of uranium to create heat and, thereby, through a heat transfer mechanism and turbines, create electricity.

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HOW DOES IT WORK?

For a nuclear reactor to create energy it is necessary for nuclear fission to take place. This occurs when an atom is split into smaller particles and an enormous amount of energy is released in the process. Uranium is used as the fuel for the reaction as it is radioactive, and is therefore unstable enough to be broken down into smaller parts. The uranium atom absorbs a neutron and splits into two equal parts and energy is created. This kinetic energy becomes heat energy as the particles slow down, and it is this heat energy, which is used to produce electricity (see Extras / Links for more information on the science involved). The heat is moved through a transfer medium, such as water, and is used to turn water into steam. This steam turns a turbine, which is connected to a generator. As the turbine turns the generator it creates electricity, which is then transferred to the consumers.

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IS IT RENEWABLE?

Nuclear power is renewable as it doesn't use fossil fuels or other non-renewable resources in the production of energy; however it isn't as renewable as some of the alternatives, such as wind or solar power, which rely solely on natural phenomena to create their power. In the short term it is unlikely that uranium will run out, but eventually it will. Therefore we can say that nuclear power is only renewable in the short term.

APPLICATIONS OF NUCLEAR POWER

About 440 nuclear reactors are used around the world to produce about 17% of the world's electricity but in theory nuclear fission can be used for much more. At the end of the Second World War the Allies secured victory by dropping the atomic bomb on Japan. The bomb uses the same principles of splitting the atom as the nuclear reactors do in creating electricity. On a smaller, less destructive scale, the theories of nuclear fission are used daily in medicine. Scanning devices and the treatment of cancer both use the radiation from splitting an atom.

ADVANTAGES

• As an alternative to normal coal-based electricity production nuclear power is favourable as it is much more efficient than coal (250g of uranium produces 20000 times more electricity than 250g of coal) and is far less polluting, especially to our atmosphere, as no harmful greenhouse gases are emitted. (ie. carbon monoxide, sulphur dioxide, nitrogen oxide etc.).
• It is generally a reliable process that can be counted on to produce electricity for many years (average availability over three years is about 80%).
• The amount of waste produced each year would cover only your dining room table!
• The waste is stored in fire-, water-, and earthquake-proof capsules to ensure safety.

DISADVANTAGES

• There is pollution in the form of radioactive waste but with new technologies the process is becoming cleaner and safer each year.
• The possibility of radiation leakage or plant meltdown. This is possible in theory and has happened in the past (Chernobyl in Russia) but nowadays there are procedures in place to ensure safety.
• There are problems and dangers, which could lead to accidents. The power stations are all manually run and human error could lead to possible accidents.
• The reactors also have a very expensive capital outlay in the beginning, although the costs are cheaper in the long run.
• The plants do require downtime for maintenance (see Interesting Information below).

NUCLEAR POWER IN SOUTH AFRICA

The only nuclear power plant in South Africa, and on the whole continent, is situated just outside Cape Town. Koeberg Power Station is instrumental in providing electricity to Cape Town and to the whole of the Western Cape. The Station employs about 1200 people and was brought online on the 4th April 1984. It is able to produce 1800MW (megawatts) of electricity by means of its two 900MW units. Radioactive waste is either transferred to a remote site in the Kalahari Desert (600km away) or if the waste is highly reactive it is stored onsite in special containment facilities.

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INTERESTING INFORMATION

One of the common worries of nuclear power is the danger of radiation leaks, espacially after the horrors of Chernobyl. In Cape Town we are fortunate that Koeberg is located on a geologically sound platform, far beyond the internationally prescribed 10km distance from city limits. The walls of reactors are also thick enough to withstand an earthquake or even a plane crash.

As the City of Cape Town has seenthe plants aren't completely reliable. In 2006 there were many blackouts in the Cape Town metropole, caused by faults and breakdowns in the Koeberg plant. Maintenance was being carried out on the one generator when the other generator failed and shut down - causing blackouts for months during winter.

Koeberg is situated the furthest South of any nuclear reactors in the World.

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