Nuclear & Particles

Question 1

Describe method to determine 1/2 life

Answer 1

Take background count over atleast 3 mins
Take count due to source over same time
Use stopwatch
Corrected count = count due to source - background count
Calculate count per minute
Use Geiger muller tube & counter
Hold source at arms length when transferring
Store in lead box
Use tongues to hold source

Question 2

Difference between fission & fusion in terms of practicality

Answer 2

Tech
• Fission: tech already established
• Fussion: tech not yet established

Reaction
•Fission: chain reaction is self sustaining once initiated
•Fussion: high amounts of energy needed to initiate and continue reaction

Fuel
•Fission: finite amount of uranium
•Fussion: Fuel available from sea

Waste
• Fission: makes long half life radioactive waste
• Fusion: no radioactive waste

Safety
• Fission: possibility of accident
• Fusion: unlikely to make serious accident or no leakage of radioactive material

Question 3

How is fission induced and controlled in nuclear reactor

Answer 3

•U-235 absorbs neutron
•Becomes unstable U-236 nuclei
•U-235 undergoes fission
•Resulting in daughter nuclei and fats neutrons as products
•Moderator slows so they can be absorbed by U-235 nuclei
• Process repeats to make chain reaction
• Controlled by raising & lowering control rod which absorb excess neutrons
• Allows one neutron per fission to cause further fission