Energy Resources - Nuclear Flashcards
What is nuclear fission?
The process in which a large nucleus splits into two smaller nuclei and releases energy
What are the two most common nuclear fuels?
- Uranium (235)
- Plutonium
What is a fissile fuel?
A fuel which can be used in nuclear reactors as it can be split by neutrons in a self-sustaining nuclear chain reaction
What is nuclear fusion?
The process in which two nuclei (usually isotopes of H) merge to form a single heavier nucleus and release energy
What are the main advantages of nuclear energy?
- Very high energy density
- Uranium reactors are developed
- Easy to convert to electricity
What are the main disadvantages of nuclear energy?
- Non-renewable
- High embodied energy
- Many environmental impacts
What are the new methods of extracting uranium?
- Polymer adsorption in seawater
- Phosphate mining
- Extraction from coal ash
What is a traditional nuclear reactor known as?
Light-water reactor
What are the three new reactor designs?
- Molten salt reactors
- Plutonium reactors
- Thorium reactors
What happens in a molten salt reactor?
Molten salt is used as a reactor coolant in place of water
What is the main advantage of MSRs?
The reactor can operate at higher temperatures than LWRs (without needing high pressure to prevent coolant boiling)
What safety feature does an MSR have?
A plug which melts when temperature becomes too high, releasing fuel from reactor core to stop chain reaction
What are the disadvantages of MSRs?
- Concerns over high temperatures
- Molten salt is corrosive
What are the two main isotopes of uranium?
- Uranium-235
- Uranium-238
What is the difference between uranium-235 and uranium-238?
Uranium-235 is a fissile fuel whereas uranium-238 is non-fissile
What type of fuel is uranium-238?
Fertile
How does a plutonium reactor work?
Fertile uranium-238 is bombarded with neutrons to make it fissile, producing plutonium-239
What is the main advantage of plutonium reactors?
Uranium-238 is much more abundant than uranium-235
What is the main disadvantage of plutonium reactors?
Would require a breeder reactor, increasing construction costs
How do thorium reactors work?
Thorium-232 is a fertile fuel which can be made into fissile U-233 when bombarded with neutrons
What are the main advantages of thorium reactors?
- Thorium fuel is used within the fuel rods so no breeder reactor is required
- Waste has a shorter half-life
What are the main sources of nuclear fusion fuel?
- Hydrogen-2 (deuterium)
- Hydrogen-3 (tritium)
What five conditions are required for nuclear fusion?
- Very high temperature
- Heavy nuclei
- H in the form of plasma
- Magnetic field
- Vacuum
Why does fusion require very high temperature?
Increases Ek and therefore the chance of nuclei collisions
Why does fusion require heavy nuclei?
Greater momentum to repel like charges (+)
Why does fusion require H in the form of plasma?
Concentrates H in one place
Why does fusion require a magnetic field?
Holds the plasma centrally in the vacuum so it does not make contact with the sides of the reactor
Why does fusion require a vacuum?
To prevent the plasma being cooled by any air
What is a toroidal reactor?
A torus-shaped reactor which can potentially be used for fusion generation
What is laser fusion?
A potential fusion generation method that requires no plasma and directs laser beams at heavy H isotopes
What is the main advantage of laser fusion?
Does not require all five conditions for nuclear fusion
