Nuclear fission and fusion

Nuclear fission

the splitting of a large and unstable nucleus

Spontaneous fission is rare, for the fission to occur it needs to_

first absorb a neutron

How does nuclear fission work?

1. The unstable nucleus undergoing nuclear fission splits into 2 smaller nuclei.

2. It also emits 2 or three more neutrons + gamma rays

3. Chain reaction

What is an explosion caused by a nuclear weapon caused by?

Uncontrolled chain reaction

How do we control the rate of fission?

Control rods that are lowered into the reactor to absorb neutrons - slows down reactions

What do we use the energy from nuclear fission for whilst the control rods are in action?

The energy produced is used to heat up water, the steam is then used to drive the turbines which generates electricity.

What is nuclear fusion?

The joining of two light nuclei to form a heavier nucleus.

What happens to some of the mass during nuclear fusion?

Some of the mass may be converted into the energy of radiation.

Pros of nuclear fusion?

Pros: abundant source of energy, no pollution, no risk of meltdowns

Cons of nuclear fusion?

Only happens at really high temperatures

Pros of nuclear fission?

Uranium or plutonium is relatively cheap + produces large and steady amount of energy

Doesn't produce greenhouse gases

Cons of nuclear fission?

Very expensive to build

Nuclear waste is expensive to get rid of - buried underground in special bunkers

Risk of major disaster if malfunctions

Superstitions people don't like nuclear energy (scared)