Nuclear decay and nuclear energy

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Olivia

Cards (62)

What is the process of splitting a nucleus called?
Nuclear fission
What is nuclear fission? 
The splitting of a large nucleus to produce two smaller ones
What is nuclear fission used in?
NucLear power reactors
What is fission another word for?
Splitting
What can the absorption of slow neutrons induce?
Fission is particular nuclei, which are referred to as the fissile nuclei
What can neutrons emitted from fission lead to?
A sustainable chain reaction
What happens if neutrons are moving too fast?
Fission will not occur
What is a nuclear chain reaction?
A nuclear chain reaction occurs when a neutron splits a nucleus, releasing more neutrons, which in turn go on to split even more nuclei.
What isotopes are normally fused as the fuel in nuclear reactors?
Uranium or plutonium
Why are uranium or plutonium isotopes used as fuel in nuclear reactors?
Their atoms have relatively large nuclei that are easy to split, especially when hit by neutrons
What happens when uranium-235 or plutonium-239 nucleus is hit by a neutron?
The nucleus splits into two daughter nuclei which are radioactive
Two or three more neutrons are released
Energy is released in the form of kinetic energy of the particles produced
What is a chain reaction?
When the additional neutrons also hit other nuclei and cause them to split. Even more neutrons are then released, which in turn can split more nuclei.
What is controlled in nuclear reactors?
The chain reaction to stop it moving too quickly
Many of the fission products are also radioactive and they decay with a large range of half-lives.
Nuclear reactors use the heat from reactions in the nuclear fused to boil water
The steam from the boiling water makes a turbine spin, which in turn makes the generator turn.
What is the difference between conventional power stations and nuclear power stations?
Nuclear power stations do not release carbon dioxide, conventional ones do.
What do nuclear power stations not contribute to?
Global warming
Do nuclear power stations contribute to global warming?
No
Are uranium and uranium oxide renewable resources?
No
Why are nuclear fuels often not renewable resources?
Their supplies are limited
How is ionising radiation in the reactor prevented from escaping?
By steel and concrete walls
Why is preventing ionising radiation from escaping reactors important?
As radiation can cause cancer
Is the waste produced from nuclear power stations harmful?
Yes
Why is the waste produced from nuclear power stations harmful?
As its radioactive
What is a waste product from nuclear reactors?
Plutonium
What can plutonium be used to make?
Nuclear bombs
Why must nuclear reactions be controlled?
So that nuclear reactions like those seen in nuclear bombs do not happen in power stations
What do the moderator and control rods do?
Control the rate of reaction in the core of the nuclear reactor
What do most nuclear reactors use as a moderator?
Water
What substance can also act as a coolant in a reactor?
Water
What do some reactors use as moderator?
Graphite rods
In a power station, only one neutron is allowed to collide with a nuclei after a collision. The other neutrons released by the collision would cause a nuclear explosion if moveable control rods did not absorb them.
What are the control rods?
Neutron-absorbing rods
Where are control rods inserted?
Into the spaces between the fuel rods
What are control rods usually made from?
Boron
What happens when the boron control rods are moved down in the reactor?
It slows the reaction by absorbing more of the neutrons
What happens when the boron control rods are moved up in the reactor?
Fewer of the neutrons are absorbed
What does moving the control rods up and down mean?
That the reaction remains constant and explosions do not occur.
The nuclear fuel rods in a reactor can be radioactive for a very long time and have to be stored carefully