Nuclear Fission And Nuclear Fusion Flashcards
What are isotopes
Different forms of the same element they have the same amount of protons but a different amount of neutrons
Sir hey have the same atomic number but different mass numbers
What does radioactive mean
It means that unstable nuclei decay into other elements giving out radiation
It’s is a totally random process
What does ionising mean
When an atom loses or gains an electron it loses or gains charge and becomes an ion
This is ionisation
Alpha beta and gamma cause this to happen therefore they are ionising radiation
How do alpha particles work
They have a large positive charge when they pass close to an atom they pull a negative electron away
How do beta particles work
They are negatively charged so when the pass another atom the repel one of the atoms electrons away from it
How do gamma rays work
They orbit the atom and pass energy to it if an electron gets enough energy it can break free
What is alpha like
They are two protons and two neutrons
They are quite big heavy and slow
They have a strong positive charge
They are strongly ionising but don’t penetrate far and can be stopped easily
What us beta like
They are quite fast and quite small
They’re electrons
They have a negative charge
They are moderately ionising and penetrate moderately far
For every beta emitted a neutron turns to a proton in the nucleus
What are gamma rays like
Ver small and very fast they can penetrate far but aren’t that ionising
What blocks the three types of radiation
Alpha -paper and card board
Beta - thin aluminium
Gamma - think lead
What is nuclear fission
A type of nuclear reaction that is used to release energy from uranium or plutonium atoms
What happens in nuclear fission
A slow moving neutrons is fired at an isotope of uranium
The neutron is absorbed by the nucleus making it unstable and causing it to split
Two new lighter atoms are formed and thermal energy is released
All new nuclei are radioactive and unstable because they have the wrong number of neutrons
Each time uranium splits it also spits out neutrons which can cause a chain reaction from
How do nuclear power stations work
In the nuclear reactor a controlled chain reaction of uranium takes place
The heat energy produced is used to boil water to drive a steam turbine which turns the generator
How are chain reactions controlled
Control rods are often made of boron they limit the amount of fission by absorbing excess neutrons they are placed in between the fuel rods and are raised and lowered to control the reaction if it wasn’t controlled then it could cause an out of control reaction and explosion
How does a nuclear reactor work
The neutrons released in fission reactions have lots of energy if they are moving slow enough they can be captured by the uranium nuclei in the fuel rods allowing fission to happen
To do this uranium fuel rods are placed in water to slow down the fast moving electrons
This creates a steady rate of nuclear fission where one new neutron produces another fission
