1. Nuclear chain reactions
When a uranium-235 nucleus undergoes induced fission
after collision with a neutron, it breaks up into two smaller
nuclei and two neutrons. These are called fission neutrons.
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2. Nuclear chain reactions
When a uranium-235 nucleus undergoes induced fission
after collision with a neutron, it breaks up into two smaller
nuclei and two neutrons. These are called fission neutrons.
These fission neutrons can go on to cause further fission
events, which will produce further neutrons, and so on,
causing a chain reaction.
chain reaction
The smallest amount
of mass needed to
sustain a chain
reaction is called a
critical mass.
fission
neutron
2 of 39 © Boardworks Ltd 2010

3. Nuclear chain reactions
When a uranium-235 nucleus undergoes induced fission
after collision with a neutron, it breaks up into two smaller
nuclei and two neutrons. These are called fission neutrons.
These fission neutrons can go on to cause further fission
events, which will produce further neutrons, and so on,
causing a chain reaction.
3 of 39 © Boardworks Ltd 2010

4. Nuclear chain reactions
When a uranium-235 nucleus undergoes induced fission
after collision with a neutron, it breaks up into two smaller
nuclei and two neutrons. These are called fission neutrons.
These fission neutrons can go on to cause further fission
events, which will produce further neutrons, and so on,
causing a chain reaction.
chain reaction
The smallest amount
of mass needed to
sustain a chain
reaction is called a
critical mass.
fission
neutron
4 of 39 © Boardworks Ltd 2010

5. Energy from induced fission
A nuclear reactor uses a controlled chain reaction to produce
heat to produce steam for a generator. Apart from the source
of heat, it works in the same way as a coal-fired power station.
5 of 39 © Boardworks Ltd 2010

6. Energy from induced fission
A nuclear reactor uses a controlled chain reaction to produce
heat to produce steam for a generator. Apart from the source
of heat, it works in the same way as a coal-fired power station.
1. Reactor
produces
heat.
6 of 39 © Boardworks Ltd 2010

7. Energy from induced fission
A nuclear reactor uses a controlled chain reaction to produce
heat to produce steam for a generator. Apart from the source
of heat, it works in the same way as a coal-fired power station.
1. Reactor
produces
heat.
2. Hot coolant from
core heats water to
produce steam.
7 of 39 © Boardworks Ltd 2010

8. Energy from induced fission
A nuclear reactor uses a controlled chain reaction to produce
heat to produce steam for a generator. Apart from the source
of heat, it works in the same way as a coal-fired power station.
1. Reactor 3. Steam powers
produces turbine generator.
heat.
2. Hot coolant from 4. Steam cooled
core heats water to and condensed by
produce steam. cooling tower.
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