1. Nuclear Reactions Fission and Fusion

2. Nuclear 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.

3. Nuclear Fission There are 2 types of fission that exist: 1. Spontaneous Fission 2. Induced Fission

4. Spontaneous Fission Some radioisotopes contain nuclei which are highly unstable and decay spontaneously by splitting into 2 smaller nuclei. Such spontaneous decays are accompanied by the release of neutrons.

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

6. The Fission Process A neutron travels at high speed towards a uranium-235 nucleus. U 235 92 n 1 0

7. The Fission Process A neutron travels at high speed towards a uranium-235 nucleus. U 235 92 n 1 0

8. The Fission Process A neutron travels at high speed towards a uranium-235 nucleus. U 235 92 n 1 0

9. The neutron strikes the nucleus which then captures the neutron. The Fission Process U 235 92 n 1 0

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

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

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

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

14. It then splits into 2 fission fragments and releases neutrons. The Fission Process 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0

15. It then splits into 2 fission fragments and releases neutrons. The Fission Process 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0

16. It then splits into 2 fission fragments and releases neutrons. The Fission Process 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0

17. It then splits into 2 fission fragments and releases neutrons. The Fission Process 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0

18. Nuclear Fission Examples U 235 92 + Ba 141 56 + n 1 0 3 n 1 0 + Kr 92 36 U 235 92 + Cs 138 55 + n 1 0 2 n 1 0 + Rb 96 37

19. Nuclear Fusion In nuclear fusion, two nuclei with low mass numbers combine to produce a single nucleus with a higher mass number. H 2 1 + He 4 2 + n 1 0 H 3 1 + Energy

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 H 2 1 H 3 1

24. The Fusion Process

25. The Fusion Process

26. The Fusion Process

27. The Fusion Process

28. The Fusion Process He 4 2 n 1 0

29. The Fusion Process He 4 2 n 1 0

30. The Fusion Process He 4 2 n 1 0

31. The Fusion Process He 4 2 n 1 0