NUCLEAR FUSION

A REVOLUTIONARY scientific breakthrough is thought to have brought humanity a step closer towards limitless clean energy from nuclear fusion.

Since the 1950s, scientists and researchers have been working tirelessly towards the “holy grail” of creating more energy from nuclear fusion than they put in.

Now US government scientists in California have reportedly done it, by aiming the world’s largest laser at a nuclear target the size of a peppercorn.

The result, from a nuclear reaction reaching three million degrees Celsius, is apparently 2.5 megajoules of energy, from 2.1 megajoules of laser energy.

Nuclear fusion is preferable to nuclear fission, which is currently used to power the planet alongside fossil fuels and renewable power.

That is because nuclear fission splits heavy atoms like uranium or plutonium, to create energy, producing potentially dangerous radioactive waste that must be stored.

Nuclear fusion creates energy by bringing atoms together, instead of splitting them, and has no waste products, making it clean energy.

Unlike coal, the supply is limitless, usually requiring just two materials called deuterium and tritium, which are slightly different versions of hydrogen and found in sea water and mineral springs.

A small cup of this fuel could one day be used to power a house for hundreds of years.

The breakthrough at the federal Lawrence Livermore Laboratory in California was achieved using a laser pulse amplified a quadrillion (a million billion) times and split into 192 different pulses.

These enter a hohlraum – a gold container – and hit a tiny capsule of deuterium and tritium, creating shockwaves which produce vast amounts of  energy, in a process called inertial confinement fusion.

Significant engineering challenges remain, including how to cut the cost of nuclear fusion, harness the energy produced, run it through a turbine and get it into the National Grid.

Most experts believe this won’t be possible until 2045, but some say it could be done in a decade and is likely to be achieved using a different type of nuclear fusion called magnetic fusion.

But whether it is using magnets or lasers, the experts agree it is the main hope for escaping the climate crisis.

Sir Robin Grimes, professor of material physics at Imperial College London, said: “This is a key step towards commercial fusion – the technology which will ensure our survival on Earth, providing enough energy, with a low impact on the environment, to hugely reduce our contribution to climate change.”

Jeremy Chittenden, professor of plasma physics at Imperial, said: “If what has been reported is true and more energy has been released than was used to produce the plasma, that is a true breakthrough moment.”

Nuclear fusion, if it can be scaled up and made to run more continuously, could in future be almost zero-carbon.

However, some experts point out that the amount of energy used for the entire system containing the laser means, technically, scientists are unlikely to have yet produced more energy from nuclear fusion than was put into it.

The US energy secretary, Jennifer Granholm, made the announcement of a “major scientific breakthrough”.

– Diagrammatic representation of how nuclear fusion works. Source: BBC