Nucelar Fission/fusion

Question 1

HOW do the release of neutrons cause a chain reaction in nuclear fission

Answer 1

1) the neutron released can go on to be ABSORBED by another nucleus
2) e.g uranium-235
3) causing the unstable nucleus to split and release more neutrons
4) the process then repeats ; chain reaction

Question 2

Define: nuclear fusion

Answer 2

When two lighter nuclei join to form a heavier nucleus

Question 3

Why has nuclear fusion not been able to be reproduced on earth

Answer 3

It requires extremely high temperatures

Question 4

Where does the energy in nuclear fusion come from?

Answer 4

A very small part of the particle’s mass being converted into energy

Question 5

Define: nuclear fission

Answer 5

The splitting of a large, unstable nucleus into two smaller, daughter nuclei

Question 6

Why is uranium-325 specifically most used in nuclear reactors

Answer 6

It has a half life of 700 million years
-low activity and long half life
-means it produces energy very slowly

Question 7

WHY does nuclear fusion requires such high temperatures and pressures?

Answer 7

Because of ELECTROSTATIC REPULSION between the protons of the nuclei
Requires a lot of energy to overcome this repulsion, and allow the nucleus to fuse

Question 8

What do control rods do?

Answer 8

Absorb neutrons
-number of neutrons absorbed varies with change in depth

Question 9

What does the moderator do?

Answer 9

Slows down neutrons
The fast-moving neutrons released from the fission collides with the molecules of the moderator, causing them to lose momentum

Question 10

What does shielding do?

Answer 10

Absorbs hazardous radiation
Steel/concrete wall about 2m thick that absorbs all radiation
To ensure safety of workers around