P2.6.1 - AQA GCSE Physics Unit 2

 

 

P2.6.1

Nuclear fission

a) There are two fissionable substances in common use in nuclear reactors:

uranium-235 and

plutonium-239.

The majority of nuclear reactors use uranium-235.

b) Nuclear fission is the splitting of an atomic nucleus.

 

 

 

c) For fission to occur the uranium-235 or plutonium-239 nucleus must first absorb a neutron.

d) The nucleus undergoing fission splits into two smaller nuclei and two or three neutrons and energy is released.

 

e) The neutrons may go on to start a chain reaction.

Candidates should be able to sketch or complete a labelled diagram to illustrate how a chain reaction may occur.