Topic 7c Fission and fusion

what enters the unstable nucleas to start the fission process

a nuetron

In fission an unstable nucleas?

Splits into two

to form ?

daughter nuclei

What is created in the fission process(3)(refer to energy transfer)

energy released from fission reactions as energy is transfered from:

the nuclear store of the target nucleas

to the kinetic store of the fission products
leads to neutrons colliding with other nuetrons and therefore a chain reaction happening

also releases gamma, 3 nuetrons and kinetic energy

In a nuclear power station, where do nuclear fission reactions occur

In the nuclear reactor

What is the role of the concrete chamber in a nuclear power station

To prevent ionising radiation from penetrating through the reactor walls

What is the role of the moderator in a nuclear power station

Slows down the neutrons enough so that they can trigger a fission reaction

What is the role of the control rods in a nuclear power station

To absorb neutrons so that the rate of the fission reaction can be controlled

What are control rods made of

Cadmium or boron

What is the role of fuel rods in a nuclear power station

Source of unstable nuclei which can undergo nuclear fission

What are fuel rods made out of

Uranium-235

What is the first step in how electricity is created in a nuclear reactor

The fission reaction generates heat energy in the reactor

What is the heat from fission used for in a nuclear power station

To heat up pressurised water

What does the pressurised water do in a nuclear power station

Goes into a steam generator to turn the water into steam

What does the steam do in a nuclear power station

Spins a turbine, which is connected to a generator

What does the generator contain in a nuclear power station

A magnet inside a large coil of wire

What happens when the magnet is rotated inside the wire in a nuclear power station

It generates an electrical current inside the wire

Nuclear fusion

When two smaller nuclei join to form a heavier nucleus

Nuclear fission

The splitting of a large, unstable nucleus into two smaller nuclei

What is formed after fusion

A larger nucleus, a neutron and a large amount of kinetic energy

The mass of the products of fusion is

Smaller than the two reactant isotopes that were used in the process

Fusion is the energy source for

The sun and all other stars in the universe

Why can nuclear fusion happen in the sun

• Nuclear fusion requires

  • extremely high temperatures

  • extremely high pressures

• These conditions are required because of the electrostatic repulsion between protons

  • Since protons have a positive charge, they repel each other

  • Therefore, to overcome this repulsion, protons must have very high kinetic energies to allow them to get close enough to fuse

moderators are made from

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