Nuclear Fission

This lesson covers:

  1. What 'nuclear fission' is
  2. How a 'chain reaction' occurs in a nuclear reactor
  3. The pros and cons of nuclear power

stable / unstable / combining / splitting


Nuclear fission is the up of a large and nucleus, into smaller nuclei.

splitting
unstable

0

/

2

Spontaneous fission is when the fission is unforced and the atom splits by itself.


Is spontaneous fission common or rare?

Common

Rare

0

/

1

proton / neutron / stable / unstable


Fission can occur by an atom's nucleus absorbing a and becoming even more . The neutron helps to split the nucleus. 

neutron
unstable

0

/

2

Steps for a nuclear fission chain reaction


Diagram showing the steps of a nuclear fission chain reaction with uranium-235 splitting into smaller nuclei and releasing energy.


daughter / gamma / chain / split / neutron


  1. It starts with an unstable nucleus like uranium-235.
  2. A is then fired at the unstable nucleus and causes it to apart.
  3. The unstable nucleus splits into two '' nuclei and two or three neutrons, while also emitting lots of energy in the form of radiation.
  4. The two or three neutrons that were released are then absorbed by other unstable nuclei and this repeats the process from step 3.
  5. This process then occurs over and over again in what we call a reaction.
neutron
split
daughter
gamma
chain

0

/

5

How nuclear power stations generate electricity


Illustration of nuclear reactors with cooling towers and steam.


generator / turbines / gamma / beta / alpha / water


  1. Whenever unstable nuclei split apart they release lots of radiation.
  2. This gamma radiation is then used to heat liquid into steam.
  3. As the steam rises it turns , and the kinetic energy of those turbine is converted into electricity by a . 
gamma
water
turbines
generator

0

/

4

Ensuring safety in nuclear reactors


It is very important that the chain reaction of nuclear reactors is kept under control to avoid a nuclear meltdown. 


To help keep the reaction stable, we can lower rods into the nuclear reactor which neutrons and down the chain reaction.

control
absorb
slow

0

/

3

What are the main pros of nuclear power?

(Select all that apply)

Nuclear power plants can produce large and steady electric power

Nuclear fuel such as uranium or plutonium is relatively cheap

Nuclear power plants generate renewable energy

Nuclear power does not produce any greenhouse gas

0

/

3

State and explain three cons of nuclear power.

0

/

3