

Nuclear power explained

By OVO Energy Wednesday 28 February 2018

What is nuclear power?

Nuclear power is electricity created in a nuclear power plant. It’s done through a process called nuclear fission, where uranium atoms are split into smaller atoms to produce electricity.

The potential power locked inside a uranium atom is mind-boggling. 1 kg of coal will give you 8 kWh of heat, whereas 1 kg of uranium-235 will create a ridiculous 24,000,000 kWh. That’s 2 to 3 million times more! All that oomph from something the size of a bag of sugar.

What’s an atom? What’s uranium?

Rewind (or fast forward!) to our science GCSEs… Atoms are tiny particles that make up every object in the universe. And uranium is an element from the periodic table – it’s a radioactive, silvery metal.

How does a nuclear power plant work?

Nuclear power plants work very much like traditional power stations.

Traditional power plants burn coal, oil and natural gas, and use them to boil water into steam. The steam then turns the turbines that drive a generator to produce electricity.

So what’s the process for generating nuclear energy?

Nuclear power plants follow the same process, but they don’t burn anything. Instead they use nuclear fission to split uranium atoms inside a nuclear reactor. The energy heats the water, creates steam and so on.

What’s a nuclear reactor?

A nuclear reactor sits inside a nuclear power plant – it’s where the splitting of uranium atoms takes place. It’s designed to allow a controlled chain reaction. Without it, the chain reaction would spiral out of control and cause an explosion.

How is nuclear power made? How do you split uranium atoms?

There are different kinds of uranium. But the one used in nuclear power plants is called uranium-235, as these atoms are easiest to split in two.

Rods of uranium are arranged in bundles and put into a giant water tank inside a nuclear reactor. When the reactor is running, high-speed particles (neutrons) hit the uranium atoms and split them. This releases lots of energy and more neutrons, which go on to split other uranium atoms, triggering a chain reaction.

The energy heats up the water, which produces the steam, which turns the turbines and makes the electricity. Simple!

What is the carbon footprint of nuclear power?

Alongside solar and wind, nuclear power has one of the smallest carbon footprints of any energy source. Most of the carbon dioxide (CO2) emissions created by nuclear power plants are actually released while they’re being built or while they’re processing fuel – not while they’re generating electricity.

Nuclear power plays a key role in the UK government's Clean Growth Strategy, released in October 2017. It outlines how it’s going to reduce carbon emissions across the whole economy. As part of the Climate Change Act, the government has committed to cutting CO2 emissions by at least 80% from 1990 levels by 2050.

Is nuclear power a renewable source of energy?

No, as there isn’t an unlimited supply of uranium or other fuel sources on Earth. But it looks like there will be enough uranium to run the world’s reactors for another 200 years.

How safe is nuclear energy?

It’s reassuring to know that nuclear energy is one of the most fiercely regulated industries in the UK. It is controlled by a wide range of laws covering the storage, transport and use of nuclear materials. On the rare – but catastrophic – occasions when there has been an accident at a nuclear facility, governing bodies across the world have immediately introduced greater regulation and cooperation, nationally and often internationally.

One of the most recent accidents was caused by the tsunami that hit Japan in March 2011 after the Tōhoku earthquake. It flooded the reactors at the Fukushima 1 nuclear power plant, causing a loss of coolant followed by nuclear meltdowns and the escape of radioactive materials.

In its wake, the UK government commissioned a thorough review of nuclear power in the UK. It revealed no fundamental safety weaknesses but concluded that the industry could be made even safer by learning lessons. These included reliance on off-site infrastructure such as the electrical grid supply in extreme events, emergency response arrangements, layout of plant, risks associated with flooding, planning controls around nuclear facilities – and prioritising safety reviews (see full report).

Nuclear waste is classified as high level, intermediate or low level, depending on how much residual radioactivity is left in it, and must be dealt with according to its defined level. It is usually transported by rail or sea in steel containers that are purpose built for radioactive materials. They can stand up to extremes of temperature and pressure, whether they’re ultimately buried on land or dropped in the ocean.

There have never been any instances of damage to health or the environment caused by transporting nuclear waste.

Does OVO use nuclear power in its fuel mix?

No. We get most of our energy from renewables, which – in our opinion – is the best option all round. Discover exactly where our energy comes from.
