P2 Topic 5 - Nuclear Fission And Nuclear Fusion Flashcards
What are the three types of ionising radiation?
Alpha
Beta
Gamma
Define isotope.
An isotope is an atoms with more or less neutrons than the original element. Isotopes have the same atomic number but different mass numbers and they tend to be unstable or radioactive.
How do the three ionising radiations ionise atoms?
Alpha - strong positive charge pulls electrons out of orbit
Beta - negative charge pushes electrons out of orbit
Gamma - transfers a lot of energy to electrons so that they can break free from the atom
State the properties of alpha radiation.
Helium nuclei Big, heavy and slow-moving (take longer to pass an atom so higher chance of ionisation) Strong positive charge Strongly ionising Weakly penetrating
State the properties of beta radiation.
Electron Quite small and fast-moving Negative charge Moderately ionising Moderately penetrating For every beta emission from an atom, a neutron turns into proton
State the properties of gamma radiation.
High frequency electromagnetic radiation (photon)
No charge
Weakly ionising
Strong penetrative power
Define nuclear fission.
The splitting of large nuclei to release immense amounts of energy.
How does nuclear fission make use of chain reactions to split atoms?
A nucleus is fired at a uranium isotope. The isotope absorbs the nucleus and becomes unstable. This causes it to split into two lighter elements, as well as two more neutrons. These neutrons go on to collide with more isotopes, with each split, energy is also released.
How is nuclear fission used to produce electricity?
During the chain reaction, a lot of heat energy is released. This heat is used to boil water which rises and turns a turbine connected to a generator, which then produces electricity as any other power station does.
How is the chain reaction in a nuclear power plant controlled?
Boron control rods are lowered and raised from in between the fuel rods to absorb excess neutrons so that the chain reaction doesn’t go out of control.
A moderator, such as water, is also used to slow down fast moving neutrons and prevent an explosion.
Define nuclear fusion.
Joining small nuclei to produce energy.
How does nuclear fusion work?
An deuterium atom (^2H) and a hydrogen atom (^1H) are collided to create a helium atom.
State the conditions needed for nuclear fusion.
High temperatures (10,000,000 °C) High pressures
This is to counteract the repulsion of the protons
