Nuclear power has once again found itself in the headlines, but this time it’s not for a disaster such as Chernobyl or three mile island, but as a potential saviour of the environment (nuclear plants produce almost no emissions and so don’t contribute to the greenhouse gases in the atmosphere, unlike traditional fossil fuel plants) and relatively clean supplier of our global energy needs. There has been a great deal of media attention on alternatives and how they are going to help clean up the world as well as give us all of the energy we will need. But this is far from the case and alternatives are not even close to taking the burden off fossil fuels. Only two alternatives are viable and have any meaningful contribution to world energy production and they are Hydroelectricity and wind Power. Hydroelectric plants contribute over 20% to total global electricity production, but the majority of usable sites are already developed. Wind power is slowly gaining momentum and the technology is already in place, but it’s not a realistic alternative in the short to medium term. Solar, wave, geothermal, etc.. are very far behind the curve and will take many years and tens of billions of dollars of investment before or if they ever start significantly contributing to energy supplies.
But this energy shortfall has to be met somehow and so it looks as if the burden will fall on Nuclear power to do this. Environmentalists are clamouring together expressing what a terrible idea this is, but when it comes to a nation’s energy security they really don’t get a look in.
What is nuclear power
Nuclear power is basically the production of energy from atomic nuclei by the use of a controlled nuclear reaction. At present the only method in use is Nuclear fission (where one atom splits into two), but there is continued research in the area of Nuclear fusion which has been lauded as the perfect “endless” source of safe and inexpensive energy. Uranium is the “radioactive” element used in nuclear fission. How it generates electricity is that in a nuclear reactor the uranium nucleus is bombarded by a free neutron, which then yields two smaller atoms and up to three free neutrons and energy. This process can become self sustaining and produce a massive amount of energy as more free neutrons are released from the fission event than was required to initiate it. An interesting fact is that a pound of enriched uranium is equal to about a million gallons of gasoline.
Nuclear power plants
Nuclear power plants operate by capturing the energy released from the splitting of the uranium nucleus. This takes place in the reactor (which is used as a heat source) which then heats water which is carried away from the core as steam or superheated water, which is also converted to steam. This steam then drives a turbine which turns a generator and produces electricity.
The enriched uranium is usually formed into pellets about 2.5cm long. These pellets are then made into long rods which are then collected into bundles. The bundles are then submerged in water inside a pressure valve. This bundle of uranium heats the water and turns it to steam which drives a turbine.
Power plants are very similar to a standard coal fired plant, but because they emit high levels of dangerous radiation a series of extra precautions are required.
The reactor is housed in a concrete liner, which acts as a radiation shield. This is itself housed inside a large steel vessel which prevents leakage of radioactive gases or fluids.
This is then all contained within a concrete building, which is disaster proof (earthquakes, bombs.)
It was the absence of this containment level which allowed radioactive material to leave the plant in Chernobyl.
At present there are over 430 operating nuclear plants worldwide and they provide over 2% of the worlds total energy output and 15% of the worlds electricity.
Advantages and disadvantages of nuclear power
Advantages of nuclear power
• Nuclear power is considered a cleaner method of energy production than standard fossil fuels.
• It does not produce greenhouse gases (almost zero emission)
• Each plant produces a massive amount of energy.
• The plants are very well designed and run and very rarely experience problems (except from human error)
• New plants are much more efficient and safer than their older counterparts
• Nuclear power plants have very low running costs (only a small amount of Uranium is needed.)
• It’s reported that nuclear waste can be safely stored underground (although this is a heavily debated issue.)
Disadvantages of nuclear power
• It produces dangerous waste products which have to be stored underground and remain radioactive for a very long time.
• Very high start up costs
• Mining and refining Uranium is not very clean. Also the transportation costs are very high, which add to the cost of nuclear power.
The most well known nuclear disaster occurred at a nuclear power plant in Chernobyl, which is situated on the border of Ukraine and Belarus.
On April 26 1986 an explosion happened within the plant and because of the poor design, maintenance and lack of suitable containment, tons of radioactive dust were thrown into the air. A great deal of this was carried around the world but over 70% was blown over Belarus who suffered a terrible price and still continue to do so as much of their arable land and forests have been poisoned by the radioactive substances.
Nuclear power will continue to be a hotly debated source of energy production, but time is running out and many people believe that this is the only realistic way of keeping up with our growing energy demands.