| most ionising? | alpha |
| whats half life | the time it takes for half of the unstable nuclei in a sample to decay or for the activity of the sample to halve or for the count rate to halve. |
| whats contamination | Occurs when an object is exposed to a source of radiation outside the object |
| what is irradiation | indirect contact radiation |
| what is fission? | the splitting of a large atomic nucleus into smaller nuclei. |
| what is fusion | when two small, light nuclei join together to make one heavier nucleus |
| fission in a reactor | In a nuclear reactor, a neutron is absorbed into a nucleus (typically uranium-235). This causes the nucleus to become uranium-236, which is violently unstable.
The entire nucleus splits into two large fragments called 'daughter nuclei'. In addition to the 'daughter' products, two or three neutrons also explode out of the fission reaction and these can collide with other uranium nuclei to cause further fission reactions. This is known as a chain reaction.
The fast moving neutrons carry most of the energy from the reaction with them (99%) but before the neutrons can collide with fresh uranium nuclei, they need to be slowed down.
This is so that the energy can pass on to other components in the nuclear reactor, which is used to heat water to drive the turbines that turn the generators. |
| whats a control rod | stop neutrons from travelling between fuel rods and therefore change the speed of the chain reaction- boron |
| what is a fuel rod | so that the neutrons released will fly out and cause nuclear fission in other rods. - uranium |
| moderator | control the rate of reaction in the core of the nuclear reactor. - graphite |
| why high temp for fusion | in order to force the nuclei together and overcome this electrostatic repulsion. |
| What's a Becquerel? | Unit of radioactivity, 1 nuclear decay / second |
| How do you detect radiation? | Photographic film or Geiger-Müller tube |
| Why is radiation dangerous to health? | Radiation can either kill cells outright or cause mutations leading to misbehaving cells and cancer. This doesn't just come from direct exposure to a nuclear facility but also from waste so proper disposal is vitally important. |
