Fission reactors
A fission reactor contains a number of different parts:
- Radioactive materials, usually uranium or plutonium, used in nuclear reactors. - the uranium or plutonium Atoms of an element with the same number of protons and electrons but different numbers of neutrons. that will split when triggered by an incoming Uncharged subatomic particle, with a mass of 1 relative to a proton. The relative charge of a neutron is 0.. The fuel is held in rods so that the neutrons released will fly out and cause The splitting of a large nucleus to produce two smaller ones. Two or three neutrons are also released in the process. The energy from the neutrons powers a nuclear reactor. in other rods.
- Moderator - Slows down neutrons in a nuclear fission reactor. - a graphite core, for example, slows the neutrons down so that they are more likely to be absorbed into a nearby fuel rod.
- In a nuclear reactor, the control rods are used to absorb excess neutrons and control the rate of the nuclear fission reactions. - these are raised and lowered to stop neutrons from travelling between fuel rods and therefore change the speed of the A nuclear chain reaction occurs when a neutron splits a nucleus, releasing more neutrons, which in turn go on to split even more nuclei..
- A liquid used to transfer thermal energy within a system. - this is heated up by the energy released from the fission reactions and is used to boil water to drive Revolving machine with blades that are turned by wind, water or steam. Turbines in a power station turn the generators. in the power station.
- Concrete shield - the daughter products of the fission reaction are When unstable atoms give off particles that can be harmful to humans. and can be a Something that has the potential to cause harm or damage..
Many of the features of the reactor are designed to control the speed of the reaction and the temperature inside the shielding. An uncontrolled fission reaction is the basis of an A powerful and destructive bomb that gets its power from the energy released when atoms are split..
Advantages and disadvantages of nuclear power stations
Generating electricity using nuclear reactors carries high risk but offers large rewards. In operation, a very small amount of nuclear fuel will consistently generate a very large amount of electricity and generate very little polluting material. However, the financial costs of building and decommissioning a nuclear power station are very large, and the waste produced will remain radioactive - hazardous to humans and the environment - for thousands of years.
| Advantages | Disadvantages |
| Produces no polluting gases. | Waste is radioactive and safe disposal is very difficult and expensive. |
| Does not contribute to global warming. | Local thermal pollution from wastewater affects marine life. |
| Very low fuel costs. | Large-scale accidents can be catastrophic. |
| Low fuel quantity reduces mining and transportation effects on environment. | Public perception of nuclear power is negative. |
| High technology research required benefits other industries. | Costs of building and safely decommissioning are very high. |
| Power station has very long lifetime. | Cannot react quickly to changes in electricity demand. |
| Advantages | Produces no polluting gases. |
|---|---|
| Disadvantages | Waste is radioactive and safe disposal is very difficult and expensive. |
| Advantages | Does not contribute to global warming. |
|---|---|
| Disadvantages | Local thermal pollution from wastewater affects marine life. |
| Advantages | Very low fuel costs. |
|---|---|
| Disadvantages | Large-scale accidents can be catastrophic. |
| Advantages | Low fuel quantity reduces mining and transportation effects on environment. |
|---|---|
| Disadvantages | Public perception of nuclear power is negative. |
| Advantages | High technology research required benefits other industries. |
|---|---|
| Disadvantages | Costs of building and safely decommissioning are very high. |
| Advantages | Power station has very long lifetime. |
|---|---|
| Disadvantages | Cannot react quickly to changes in electricity demand. |