Nuclear Fission and Fusion

Question 1

Nuclear Fission

Answer 1

Nuclear Fission is the splitting of an atom, which releases energy

Question 2

What is the process in a nuclear reactor when uranium- 235 is split

Answer 2

• If a slow-moving neutron is absorbed by uranium-235, the nucleus can split
• Each time this happens it spits out a small number of neutrons which might go on to hit other uranium- 235
• This becomes a chain reaction
• When uranium- 235 splits it will form two new daughter nuclei, both lighter elements than uranium
• The daughter nuclei are usually radioactive

Question 3

In a nuclear reactor, what does each nucleus splitting give out?

Answer 3

• A lot of energy in kinetic energy stores of the fission products
• In a reactor, this energy is transferred to thermal energy stores to produce steam to drive a turbine

Question 4

Describe the function of the moderator in a nuclear reactor

Answer 4

• Usually graphite or water

- slows down neutrons

Question 5

Describe the function of the Control Rods in a nuclear reactor

Answer 5

• Often made of boron

- Limits the rate of fission by absorbing excess neutrons