Nuclear fission & fusion Flashcards
Nuclear power stations use what
Fission
Nuclear fission gives off
Heat
What 2 isotopes are used in power stations
Uranium 235
Plutonium 239
What is fired into a nucleus into a nuclear of an isotope to start fission
neutron
When a neutron is fired at an isotope what is produced ( 3 )
1/ Energy
2/ 2 smaller nuclei
2/ 2 or 3 more neutrons
In fission, what type of reaction happens
Chain reaction
What is the process that joins nuclei
Fusion
Why is fusion a problem
Both nuclei have positive charges
Where does fusion happen naturally
Centre of stars
Why can fusion occur in stars ( 2 )
1/ Lots of heat
2/ Large gravitational force
Advantages of fusion ( 2 )
1/ No bi products
2/ Lots of energy released
Advantages of fission ( 2 )
1/ Technology available
2/ Large amounts of energy
Disadvantages of fusion ( 2 )
1/ Not available
2/ Very high temperatures required
Disadvantages of fission ( 1 )
1/ Produces radioactive waste
What is the first stage of a star
A protostar
What is a protostar
A large cloud of hydrogen and helium the is drawn in by gravity
When does fusion occur in the life cycle of stars
Main sequence star
What is the force pushing inwards
gravity
What is the force pushing outward
Nuclear reactions
What defines the main sequence start
When the forces are balanced
What happens when fuel in the main sequence star runs scarce
It becomes a red giant or red supergiant
What happens when a red giant collapses under the force of gravity (When its the size of our sun or smaller)
It becomes a white dwarf
What happens when a white dwarf cools down because of no fusion
It becomes a black dwarf
What happens when a red super-giant collapses
A supernova occurs
What does a supernova do
Scatters elements from the star throughout the Universe
During the main sequence of stars, what is the heaviest element that can be made
Iron
What is the heaviest element that can be made during a supernova
Gold
After a supernova what 2 bodies can be made
1/ Black hole
2/ Neutron star
