Unit 2.9 Nuclear Decay and Nuclear Energy

What is nuclear fission

The splitting of large, unstable nuclei to form smaller more stable nuclei (plus the emission of spare neutrons)

What usually needs to happen to induce fission

• The unstable nuclei must absorb a neutron

What term is used to describe nuclei in which fission can be induced through the absorption of slow neutrons

Fissile nuclei

Alongside two smaller nuclei, what else is emitted in a fission reaction

• Two or three neutrons

• Gamma rays

• Energy

What form of energy do all fission product has

Kinetic energy

Name a common fissile nuclei

Uranium-235

What are the 3 main component of the core a nuclear reactor

1. Fuel rod

2. Control rod

3. Moderator

What takes place during a chain reaction in a nuclear reactor

• An unstable nucleus absorbs a neutron

• The nucleus undergoes fission and release 2 or 3 further neutrons

• These include more fission which results in a chain reaction

What is the consequence of an uncontrolled chain reaction in nuclear power station

• The rate of fission events becomes to high and results in the production of too much energy. This can lead to a nuclear explosion

How is the chain reaction in a fission reactor kept under control

• Control rod are positioned in between the fuel rods.

• The rate of fission is controlled by moving these rods up and down

• The lower the rods are inserted, the slower the rate of fission

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

To slow down the neutrons so they are travelling at speeds which allow the, to be absorbed by fissile nuclei and cause fission

What is nuclear fusion

The joining of two light nuclei to produce a heavier nucleus and release energy

Name two isotopes of hydrogen which are commonly used in a nuclear fusion

Deuterium and tritium

Which release more energy, nuclear fission or nuclear fusion

Fusion

Explain the difficult of generating energy through nuclear fusion

Requires very high temperatures which in itself requires large quantities of energy and also requires casing which can withstand them

Explain why nuclear fusion is currently not a viable way to produce energy on earth

With the current equipment and techniques, the energy required is greater than the energy produced, resulting in a net energy loss

What must the casing of a fission reactor do

Absorb any neutrons and gamma radiation that is released in the fission reactions, to prevent it from passing through to outside of the reactor

Why are fission produce particularly dangerous

They have very long half life Menai h they will remain radioactive for a very long time

What is the nuclear symbol for a neutron

What are one way to store nuclear fusion

Magnetic field