How does nuclear power work and why is the UK investing in it?

How does nuclear power work?

In non-military reactors, nuclear power is generated by bombarding uranium atoms with much smaller neutron particles.

This causes the atoms to split in a process called nuclear fission, which releases huge amounts of energy as heat.

The heat is used to boil water and produce steam which drives turbines and generates electricity.

Like fossil fuels, nuclear power uses non-renewable energy resources, but unlike coal and gas power stations, nuclear plants do not produce greenhouse gases such as carbon dioxide or methane during their operation.

Building new nuclear power stations does create emissions as a result of manufacturing the steel and other materials needed. But the total amount of emissions generated across the lifecycle of a plant is still relatively low.

Expanding the use of nuclear power therefore helps the government meet its future climate change targets - although neither Sizewell C nor any SMRs are likely to be operational before its target for almost completely clean power by 2030.

The UK has nine nuclear reactors in operation - some sites have more than one reactor - but they're ageing, and eight of them are due to close by the end of the decade.

What are SMRs and where could they be built?

SMRs work on the same principle as large power plants, using a nuclear reaction to generate heat that in turn produces electricity.

However, SMRs are a fraction of the size of a typical large reactor, and can generate up to a third of the same amount of power.

They can be built to order in factories and then transported and fitted together on location, which could make them faster and cheaper to build.

However, the cost savings are not expected to materialise until large quantities of SMRs are being built, so the first plants are likely to be very expensive.

It is not clear how much it will cost to deal with the nuclear waste generated by SMRs.