Nuclear Power Facts
Nowadays, there are over 400 nuclear power stations in operation worldwide and provide more than 15% of the world’s electricity. Do you know how it works? Where the nuclear wastage is disposed to, or it is safe enough? Should we build more power stations? Without the nuclear power, it may be difficult to provide all the electricity we want. Nuclear power- unlike coal, oil and gas-does not add to the greenhouse effect. However, some people say that the risks are too great, we should find another way of generating power or adopt a simpler lifestyle that requires less electricity. You will find out once you continue to read!
The Scientific Theory
Nuclear power uses the energy stored in the nucleus at the centre of atoms. In some very heavy atoms, the nucleus can be split into 2 smaller parts. This process, known as nuclear fission (splitting), release an enormous amount of heat, which used in a nuclear power station to boil water. The steam pushed around a turbine. This turns a generator which produces electricity.
Most of our electricity comes from power stations, which burn coal, gas or oil. But supplies of these fuels are limited, and burning them causes pollution and global warming. Nuclear power could provide electricity for thousands of years and does not add to global warming.
The fuel in most of the power station contains a special type of uranium metal called uranium-235 (it has 235 neutrons and protons of each atom). When a nucleus of uranium -235 is hit by a neutron, it splits into 2 smaller nuclei, releasing energy, gamma radiation, and more neutrons and so on. This is called a chain reaction. When a nuclear bomb detonates, an uncontrolled chain reaction causes a huge and violent explosion. However, in a nuclear reactor, a controlled chain reaction releases energy at a steady rate.
The key part of a nuclear power is its reactor. The core of the reactor contains the nuclear fuel and a material called moderator, which slow down neutrons. Without this, the chain reaction could not keep going. To slow the rate of fission, control rods are lowered into the core. The rods absorb neutrons so that there are fewer of them moving about.
In fusion reactor. temperature of about 100 million degrees Celsius(100,000,000 C) will be needed to produce nuclear fusion. There are many different ways to take the heat away to produce steam for the turbine. In a pressurized water reactor (PWR), water is pumped through the core. In an advanced gas-cooled reactor(AGR), carbon dioxide gas is used instead.
Fission turns the nuclear fuel into highly radioactive waste material. This gives off radiation, which can be extremely harmful to living things, especially if the waste gets into their body with air, food or water.
Some nuclear waste will stay radioactive for thousands of years. When removed from the reactor, it is kept as a liquid in stainless steel tanks, where it is surrounded by thick concrete to absorb the radiation and cooled by water. However, steel tank will eventually start to leak so the waste is immobilized in glass and allowed to cool before being placed underground.
Safety And Risks
A reactor cannot explode like a nuclear bomb, but an accident at a nuclear power station can have disastrous effects over a wide area. In 1986, there was a major accident at the Chernobyl nuclear power station in the Ukraine. A huge cloud of radioactive gas and dust was blasted into the atmosphere. 31 people died in the accident itself, and around 200 people suffered from radiation sickness, some of whom died later. In addition, much higher rate of cancer has been recorded in the area and cancer rates are expected to remain high for many years. Winds carried some dust as far as north-west Britain, when rain washed it down into the soil. Radioactivity in the grass meant that meat from grazing sheep was unsafe to eat.
Fusion: a safer source for the future?
Fission is not the only source of nuclear power. When the nuclei of hydrogen atoms fuse together, this too release large amount of energy. The process called nuclear fusion, and it is the way the sun gets its energy. Today, scientists and engineers are trying to solve the problem of making a fusion power station. In the 21st century, fusion power may become an important source of electricity, and it will produce almost no radioactive waste.
Should human rely on nuclear power? You name it!