The exhaust pipe that could change the world

Star power: 1kg of fusion fuel could provide the same energy as 10 million kg of fossil fuel.

Is nuclear fusion our best hope for the climate? Today, scientists are celebrating a remarkable breakthrough. But not everyone is convinced that nuclear is the safest way forward.

Dawn is breaking in Culham, a village on the banks of the Thames. It is the quintessential English countryside scene: neat hedgerows, parish church, grazing cattle. Nothing much seems to be going on.

But just a couple of miles away, at the Culham Science Centre, something big is happening. A team of top scientists shiver with excitement. They might stand on the verge of a once in a lifetime discovery.

This week, newspapers were abuzz with news that researchers at Culham had created a new system, comparable to an “exhaust pipe”, that rapidly cools the excess heat produced by nuclear fusion. It could open the door to a new form of clean, efficient energy.

Fusion is the holy grail for nuclear scientists. Today’s nuclear power is created through fission. Uranium atoms are split apart into lighter elements, releasing energy in the process. Fission relies on environmentally damaging mining, causes radioactive waste and can lead to catastrophic accidents.

Fusion reactions, by contrast, occur when two nuclei collide and combine to become a heavier element. We see this process every day: the sun glows as a result of hydrogen atoms at its core continuously fusing into helium.

Replicating the sun on Earth has been difficult. Fusion was first achieved in 1951 when the United States Atomic Energy Commission tested a boosted fission weapon on the Pacific island of Engebi. But it took until 1991 for scientists to achieve a controlled release of fusion power.

It remains tricky to master. Fusion requires a precise balance of temperature, pressure and magnetism. All attempts to date have consumed more energy than they produce.

Temperature is a major hurdle. A gas must be at 150 million C to create a reaction. The heat this generates can melt a reactor’s tiles, which are expensive to replace. The system invented at Culham reduces the temperature to about 300C, similar to that of a car engine.

A working fusion reactor could revolutionise how we create energy. Fusion can turn 1kg of fuel into 1,500 megawatts of electricity, enough to power over a million houses for a year. It would take about 10,000 tonnes of coal to do the same.

Unlike fossil fuels, fusion is carbon-free and does not produce greenhouse gasses. And unlike nuclear fission, it does not produce nuclear waste. As Nobel Prize-winning physicist Stephen Hawking put it: “It would provide an inexhaustible supply of energy, without pollution or global warming.”

But there are snags. Fusion is efficient, but it is non-renewable. And there remains much work to be done: the Culham team plan to create a prototype fusion plant in the 2040s. This may not be enough time to save us from climate change.

Some scientists have questioned fusion’s safety. It has already been used to boost missiles. Widespread fusion reactors could enable dangerous governments to develop world-ending WMDs secretly.

Is nuclear fusion our best hope for the climate?

Nuclear option

Without a doubt, some say. We are already knee-deep in the climate crisis. As environmental scientist James Lovelock writes: “there is no chance that the renewables… can power enough energy and in time”. Unlike renewable energy sources, it does not rely on specific natural conditions. Nuclear fusion may be tough to achieve, but it is the best shot we have to halt climate change.

Not at all, say others. Even with this week’s major developments, nuclear fusion remains a possibility for the future. But renewable energy works now, without the need for years of tests and expensive machinery. By drawing on natural processes such as the rays of the sun, the flow of water and the force of wind, it also allows us to live safely, and in harmony with nature.

You Decide

  1. Should we continue developing nuclear power even if it enables the creation of more nuclear weapons?
  2. Should we search out new energy sources, or attempt to reduce our energy consumption to a sustainable level?


  1. In pairs, design two posters: one to advertise an event promoting the benefits of nuclear fusion power, and one to take to a protest against it.
  2. Split into five groups. Each researching one source of energy: nuclear, solar, geothermal, wind power and hydropower. Nominate a speaker from each group to explain and advocate that energy to the class, then vote on which source should become our primary one.

Some People Say...

“Let us see how high we can fly before the sun melts the wax in our wings.”

EO Wilson (1929 — ), American biologist

What do you think?

Q & A

What do we know?
Efficient and requiring little maintenance, nuclear power is generally seen to be one of the great energy success stories of the 20th Century. A nuclear chain reaction was achieved by Enrico Fermi at the University of Chicago in 1942, but it took until 1954 for the first nuclear power plant to be built in Obninsk, Russia. Commercial nuclear production began three years later in Pennsylvania. There are now 443 nuclear reactors in operation across 30 countries, generating 10% of the world’s electricity.
What do we not know?
The future of nuclear power remains up for debate. Recent years have seen a decline in nuclear power in some countries, as old facilities reach the end of their lifespan and new reactor designs fail to pass safety regulations. In 2017 the firm that ran the first American plant filed for bankruptcy. While fusion remains under development, energy companies have sought a number of other solutions, including small, portable reactors and reactors which dissolve liquid uranium in molten salt.

Word Watch

The purest, most refined form of something.
Holy grail
A thing which is widely sought after. The original Holy Grail is a magical cup from Medieval legend, believed to have been used by Jesus at the Last Supper.
Radioactive waste
Any hazardous waste containing radioactive material. It is often stored underground.
Catastrophic accidents
There have been several nuclear crises including the 1986 Chernobyl incident in Ukraine and the 2011 Fukushima disaster in Japan.
The plural of nucleus. This is the core of an atom, made up of protons and neutrons and circled by electrons.
Boosted fission weapon
A nuclear bomb that combines a fission reaction with a small amount of fusion, greatly increasing the weapon’s strength.
A unit of power, equal to one million watts.
Weapons of mass destruction, a term used to describe any weapon that can bring significant harm to numerous people, structures or the environment.
In a way that avoids notice or attention, from Latin words meaning to “seize secretly”.

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