Nuclear Fission Flashcards

Flashcards reviewing the key concepts of nuclear fission, chain reactions, and nuclear power.

What is nuclear fission?

The splitting of a large and unstable nucleus (e.g., uranium or plutonium).

What usually needs to happen for nuclear fission to occur?

The unstable nucleus must first absorb a neutron.

What are the products of a nuclear fission reaction?

Two smaller nuclei (roughly equal in size), two or three neutrons, and gamma rays. Energy is also released.

What type of energy do all the fission products have?

Kinetic energy.

Why is a chain reaction important in nuclear fission?

The neutrons emitted during fission can go on to start a chain reaction, leading to a self-sustaining process.

How is a chain reaction controlled in a nuclear reactor?

The chain reaction is controlled to manage the energy released.

What is spontaneous fission?

Nuclear fission that happens randomly, which is quite rare.

What is induced nuclear fission?

Nuclear fission that is made to happen by making a large, unstable nucleus absorb a neutron.

What are daughter nuclei?

The 2 smaller nuclei produced when nuclear fission occurs and a large, unstable nucleus breaks apart.

What particles are released during nuclear fission?

2 or 3 neutrons and gamma radiation

What type of energy is released during nuclear fission?

Kinetic energy of the fast-moving neutrons and daughter nuclei, as well as energy in the form of gamma radiation.

What is an uncontrolled chain reaction?

A chain reaction where each reaction causes another reaction: Because 3 neutrons are produced the chain reaction will GROW if uncontrolled – this is how atomic bombs work.

What is the key component of nuclear fuel rods?

Uranium

What is the role of the control rods in a nuclear reactor?

Control rods (made of Boron) are used to absorb the neutrons and stop them moving between fuel rods which slows the chain reaction by reducing the amount of fission reactions occurring.

What do reactors use as a moderator?

Water or graphite

How does the moderator work?

The moderator slows the neutrons down which actually helps them to be absorbed by the U-235 nuclei and make fission reactions more likely

How is electricity generated in nuclear power stations?

Nuclear fuel rods get hot by fission. Then water is turned into steam. Steam turns the turbine and the Turbine turns a generator.

What is nuclear (radioactive) waste?

Any waste that is radioactive which ranges from high level waste such as the used fuel rods to low level waste such as clothing and cleaning materials.

What is the purpose of shielding a nuclear reactor core?

The reactor core is made of strong steel with a thick concrete layer to absorb radiation (gamma rays and neutrons) and stop them escaping.