Chapter 30

Question 1

What is nuclear fission?

Answer 1

Splitting of a large nucleus into two smaller nuclei (also releases 2-5 neutrons)
Large nuclei are less-tightly bound than medium sized nuclei
This releases a large amount of energy
U-235 is fuel used in many nuclear power reactors
U-235 can be induced to fission following absorption of a slow neutron, the resulting U-236 nucleus is unstable and it begins to pulsate/oscillate
Slides 28-35 April 4

Question 2

What are nuclear reactors?

Answer 2

Fuel is enriched 3% U-235 or natural 0.7% U-235
Moderator is a material to slow emitted neutrons so that they are more likely to cause subsequent fissions (water or heavy water)
Control rods: control the reaction rate by absorbing neutrons
Energy extraction: water-water or sodium-water heat exchanges to produce steam
Slides 36-40 April 2

Question 3

What is nuclear fusion?

Answer 3

The Coulomb force opposes the nuclei becoming close enough for fusion to occur
Very high temps and high densities fro significant interval of time are required for some of the nuclei to be able to fuse
Fusion reactions are called thermonuclear reactions
Slides 41-46 April 4