PHYSICS - Nuclear Decay and Energy Flashcards
What is, Nuclear Fission
The splitting of heavy nuclei into lighter nuclei and neutrons. This releases energy as gamme and KE.
How is fission induced?
Fire neutrons at an unstable nucleus
What makes a nucleus radioactive?
More neutrons than protons.
How fast must neutrons be to cause fission
Slow
What is the general equation for fission?
as sun tzu once said
U + n -> X + Y + ?n
(the mass number must balance, and proton numbers must balance)
if you’re reading this on phone it’ll probably look like nonsense, sorry
What is a fission chain reaction?
The neutrons released during fission hit other nuclei and induce them to fission aswell.
This can release like tons of energy quickly. (good for generating power (or bombs))
What is the problem if too much fission happens in a power station?
It could destroy the power station if too much energy is released
this is called a meltdown
What are the 3 parts (4??) of a nuclear reactor and what are their function
- Boron control rods - Can be raised and lowered to absorb neutrons and control the reaction
- Graphite moderator - Slows down neutrons as fast neutrons don’t do fission
- Concrete shield - Prevent radiation escaping
- Cool gas/water entering - cool the reactor
What is fusion?
Light nuclei (usually hydrogen) fuse together to make heavier nuclei (usually helium)
this releases energy somehow
How does the sun get energy, fusion or fission?
Fusion of hydrogen nuclei
What are the conditions for fusion?
High pressure - to get particles close together. protos repel so want to get away
high temperature - hydrogen nuclei are going so fast they can’t repel each other enough
What are the advantes and disadvantages of fission?
Advantages
* No CO2
* A lot of energy per unit mass
Disadvantages
* Expensive
* Nuclear waste
* The occasional accident
What are the advantes and disadvantages of fusion?
Advantages
* Cheap fuel (literally in water)
* A lot of energy per unit mass
* Safer than fission
* No nuclear waste
disadvantages
* Expensive
* Needs very high heat/pressure
* we actually haven’t managed to do it economically yet, unlike fission
