Introduction to Nuclear power
Electricity is produced by using some method to boil water to produce steam. The steam spins turbines that power the generators that produce the electricity. When people talk about nuclear power, they are referring to the part of the process that produces the heat to boil water into steam.
radioactive decay
Some elements, such as uranium, are unstable and are continuously emitting ionizing particles and radiation. This is part of the process of the element changing into another element.
This process of change by continuously and spontaneously emitting particles is called 'decay'.
One example of this process is of a carbon-14 atom that is continuously emitting radiation in the process of changing to a nitrogen-14 atom. In this case the carbon-14 atom is seen as the 'parent' and the nitrogen-14 atom is referred to as the 'daughter'.
The SI unit of radioactive decay is the becquerel (Bq), and a becquerel is one decay (often referred to as a transformation) per second. Since a piece of uranium (for example) contains a huge number of atoms, a becquerel is a tiny measure of activity and the process of decay is commonly expressed as terabecquerels (tBq) or gigabecquerel (GBq).
nuclear fission
Energy is extracted from radioactive material by increasing the rate at which the parent material emits particles per second. This is measured in bequerals, an activity of 1 MBq emits one million particles each second. This process is known as nuclear fission.
- A neutron hits a target nucleus which breaks up into neutrons and fission products. The mass of all these pieces is less than the original nucleus because 0.1% of the original mass is released as energy.
- Each neutron that is released may collide with another nucleus, which itself breaks up into neutrons and fission products. Again, more energy is released.
The resulting chain reaction that takes place does not have enough of a critical mass to cause an explosion.
A huge amount of energy is released by a very small amount of radioactive material. In fact the energy released from one kilogram of uranium-235 is approximately 82 TJ (one trillion joules of energy, or 1012 joules).
Nuclear Fission Animated
radioactivity
There are three main types of radioactivity produced by the fission process.
| Alpha particles | more on alpha particles |
| Beta particles | more on beta particles |
| Gamma particles | more on gamma particles |
| Radioactive decay and half-life | more on radioactive decay and half-life |
| The atom | more on the atom |
| The neutron | more on neutrons |