b) Fission and Fusion

Sources of nuclear energy?

Nuclear fusion

Nuclear fission

Radioactive decay

What is nuclear fission?

When one large nucleus splits into two smaller nuclei.

How is uranium-235 be slip by fission?

Uranium-235 absorbs neutron to become uranium-236.

Uranium-236 is very unstable so it splits by fission producing two smaller daughter nuclei and 2 or three neutrons.

How can a chain reaction be starters by fission?

2 or 3 neutrons that get produced from fission move away at high speeds.

Each neutron can start another fission reaction which emits further neutrons.

Role of control rods?

To absorb neutrons and control rate of reaction.

Role of moderator?

To slow down neutrons.

Role of shielding in nuclear reactor?

To absorb hazardous radiation.

Properties of nuclear fusion?

Process of nuclei joining together.

Nuclei are small(hydrogen).

Occurs in stars.

Produces large amount of energy/larger nuclei.

Requires very high temperature and pressure.

Properties of nuclear fission?

Process of nuclei splitting.

Nuclei are large(uranium).

Occurs in nuclear reactors.

Produces large amount of energy, smaller daughter nuclei, 2 or 3 neutrons.

Requires thermal neutrons to induce fission.

What is nuclear fusion?

When two light nuclei join together form a heavier nucleus.

Releases huge amount of energy.

Smaller nuclei loses mass.

Why does nuclear fusion not happened at low temperatures and pressures?

Since there’s an electrostatic repulsion between protons as protons are positively charged.