Nuclear Radiation Flashcards
Activity
The activity of a radioactive source is the number of nuclei that decay per second, measured in Becquerels (Bq)
Alpha Radiation
The radiation of a particle containing two protons and two neutrons
Strongly ionising, slow moving and positively charged so is deflected by a magnetic field
Atomic Mass Unit
1/12 the mass of a Carbon-12 nuclei
Background Radiation
Constant radiation everywhere that is due to radioactive substances in the environment
Beta-minus Radiation
Radiation consisting of a high energy electron
Mildly ionising, fast moving and negatively charged so is deflected by a magnetic field
Beta-plus Radiation
Radiation consisting of a high energy positron
Mildly ionising, fast moving and positively charged so is deflected by a magnetic field in the opposite direction to beta-minus radiation
Binding Energy
The energy required to split a nucleus into its individual nucleons
The greater the binding energy per nucleon the more stable the nucleus is
Chain Reaction
When the fission of one nuclei produces neutrons that cause fission in another nuclei
Control Rod
A rod that is inserted into a reaction vessel that stops neutrons preventing them from continuing on to cause more fission reactions
These are made from substances
that absorb neutrons without undergoing fission themself
Coolant
A fluid that passes around the reaction vessel and carries away any thermal energy produced by the fission reactions
Thermal energy is used to generate steam and drive generators to produce electricity
Critical Mass
The minimum amount of a fissile substance needed to maintain a chain reaction and a steady flow of fission
Decay Constant
The probability of a decay occurring per unit time
Fuel Rod
Contains the fissile material, each rod has many pellets of nuclear fuel which prevents the critical mass of fuel being reaching meaning the reactions are controlled
Gamma Radiation
High energy photons
Weakly ionising, travels at the speed of light and has no charge so is not deflected by magnetic or electric fields
Half-Life
The time taken for half of the radioactive nuclei to decay
Nuclear Fission
The splitting of a large nucleus to produce smaller nuclei, fast moving neutrons and energy
Nuclear Fusion
The fusing of two smaller nuclei to form a single nuclei producing a large quantity of energy
Requires very high temperatures and pressures
Nuclear Waste
The by-product of a nuclear reaction, no longer undergoing fission that can be used due to the reduced activity but the waste is still radioactive and will be for thousands of years so it is stored underground in reinforced containers
Mass Defect
The difference between the mass of the nuclei and its individual components
If this mass defect is large and positive then when a nuclei undergoes fission this mass
defect is released as energy
If this mass defect is negative then when two nuclei are fused together the mass defect is released as energy
Spontaneous Fission
The process by which a nucleus splits without absorbing a thermal neutron
Thermal Neutron
A slow moving neutron that when absorbed by an unstable nuclei causes it to undergo fission
