1. Nuclear Reactions
Fission and Fusion

2. State that in fission a nucleus of large mass splits into 2 nuclei of smaller mass numbers, usually with the release of neutrons.
State that fission may be spontaneous or induced by neutron bombardment.

3. Fission
When atoms are bombarded with neutrons, their nuclei splits into 2 parts which are roughly equal in size.
Nuclear fission in the process whereby a nucleus, with a high mass number, splits into 2 nuclei which have roughly equal smaller mass numbers.
During nuclear fission, neutrons are released.

4. Induced Fission
Nuclear fission can be induced by bombarding atoms with neutrons.
The nuclei of the atoms then split into 2 equal parts.
Induced fission decays are also accompanied by the release of neutrons.

5. The Fission Process
A neutron travels at high speed towards a uranium-235 nucleus. U
235 92 n 1

6. The Fission Process
A neutron travels at high speed towards a uranium-235 nucleus. U
235 92 n 1

7. The Fission Process
A neutron travels at high speed towards a uranium-235 nucleus. U
235 92 n 1

8. The Fission Process
The neutron strikes the nucleus which then captures the neutron. U
235 92 n 1

9. The Fission Process
The nucleus changes from being uranium-235 to uranium-236 as it has captured a neutron. U
236 92

10. The Fission Process The uranium-236 nucleus formed is very unstable.
It transforms into an elongated shape for a short time.

11. The Fission Process The uranium-236 nucleus formed is very unstable.
It transforms into an elongated shape for a short time.

12. The Fission Process The uranium-236 nucleus formed is very unstable.
It transforms into an elongated shape for a short time.

13. The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

14. The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

15. The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

16. The Fission Process
It then splits into 2 fission fragments and releases neutrons. n 1
141 56 Ba n 1 92 36 Kr n 1

17. Energy Released E = mc2 E m c2
The energy released can be calculated using the equation: E m c2
E = mc2
Where:
E = energy released (J)
m = mass difference (kg)
c = speed of light in a vacuum (3 x 108 ms-1)

18. Energy from Fission
Each uranium-235 atom has a mass of x kg.
The total number of atoms in 1 kg of uranium-235 can be found as follows:
No. of atoms in 1 kg of uranium-235 = 1/ x 10-25
No. of atoms in 1 kg of uranium-235 = 2.56 x 1024 atoms

19. The Fusion Process H 2 1 H 3 1

20. The Fusion Process H 2 1 H 3 1

21. The Fusion Process H 2 1 H 3 1

22. The Fusion Process H 2 1 H 3 1

23. The Fusion Process

24. The Fusion Process

25. The Fusion Process

26. The Fusion Process

27. The Fusion Process n 1 He 4 2
ENERGY

28. The Fusion Process n 1 He 4 2
ENERGY

29. The Fusion Process n 1 He 4 2
ENERGY

30. The Fusion Process n 1 He 4 2
ENERGY