2b.4 - Nuclear Fission and Fusion Flashcards
What is nuclear fission?
The splitting up of an atomic nuclei
How do nuclear reactions work? (4)
- Controlled chain reaction
- Atomic nuclei split up and release energy in the form of heat
- The steam heats energy
- Turns a turbine
What nuclei is used in nuclear fission?
Uranium-235 and/or plutonium-239
Explain the process of nuclear fission (4)
- Slow moving neutron is absorbed which makes it unstable, causing it to split
- Every split gives out two or three neutrons
- Splitting forms two smaller nuclei which are usually radioactive because wrong number of neutrons
- Releases lots of energy
What are products of nuclear fission? (3)
- Two smaller nuclei
- Energy
- Two or three neutrons
What are the pros of nuclear fission? (2)
- Produces lots of energy
- Fuel is cheap
What are the cons to nuclear fission? (4)
- Highly radioactive products - difficult to get rid of
- Maintenance costs are high
- Dismantling plant takes decades
- Radiation leaks
What is nuclear fusion?
The joining of small atomic nuclei
What are the advantages to nuclear fusion? (2)
- Gives lots of energy
- Doesn’t leave behind radioactive waste
What are the disadvantages to nuclear fusion? (3)
- Only happens at really high temperatures (10 million degrees)
- Needs an extremely strong magnetic field to store
- Uses more energy than is produced
What is the first stage in the life cycle of a low mass star?
Nebula - Clouds of gas and dust gather due to gravity
What is the first stage in the life cycle of a high mass star?
Nebula - Clouds of gas and dust gather due to gravity
What is formed in the nebula?
Protostars
What is the second stage for a low mass star?
Main stage star - fuse hydrogen into helium by nuclear fusion and burn for billions of years
What is the second stage for a high mass star?
Red Supergiant - The star runs out of hydrogen to fuel it so cools down and swell out
What is formed in a red supergiant?
Elements from helium to iron
What is the third stage for a low mass star?
Red giant stage
What is the third stage for a high mass star?
Supernova - A huge explosion where all elements heavier than iron are formed
Where are all elements heavier than iron formed?
Supernova
What is the forth stage for a low mass star?
White dwarf - No more light elements to use and it collapses
What happens to a high mass star after a supernova? (3)
- Elements and debris are flung into space
- Core collapses into a neutron star
- With enough mass it can become a black hole
What is the final stage for a low mass star?
Black dwarf
What did our solar system begin as?
A cloud of dust and gas
What was the first stage in the formation of the solar system?
A supernova disturbed the cloud
