P4 - Fission and fusion Flashcards
What is the process of producing electricity in a power station?
1) burn a fuel
2) heat water
3) produce steam
4) turn a turbine
5) generate electricity
What fuel is used by a nuclear power station?
Uranium.
What is nuclear fission?
The process that gives out energy in a nuclear reactor.
What happens during nuclear fission?
1) a large unstable nucleus splits up and heat energy is released
2) the decay of uranium starts a chain reaction
3) the heat produced is used to boil water to produce steam
4) the steam turns a turbine
5) electricity is produced by a generator
What is a chain reaction?
A chain reaction is a reaction that can carry on for as long as any of the uranium fuel remains.
How is a chain reaction controlled?
- boron control rods are placed between the fuel rods
- boron absorbs neutrons so fewer neutrons are available to split more uranium nuclei
- the boron rods can be raised or lowered in the reactor, controlling fission rates
What is a moderator?
Material used to slow down neutrons.
Where does nuclear fusion occur naturally?
In stars.
What happens during nuclear fusion?
Two light nuclei join together releasing large amounts of heat.
Why is fusion a preferred method compared to fission?
- there is a plentiful supply of hydrogen
- waste products of fusion are less harmful
Which scientists came up with cold fusion?
Pons and Fleischmann in 1989.
What is the issue with cold fusion?
Scientists cannot replicate results.
