Nuclear Fusion's New Record

The director of a UK science facility says scientists there will try to set a new world record in nuclear fusion.

The Jet experiment in Oxfordshire was opened in 1984 to understand fusion - the process that powers the Sun.

Prof Steve Cowley told the BBC a go-ahead to run Jet at maximum power would allow scientists to try for the record by the end of the decade.

This could bring Jet up to the coveted goal of "breakeven" where fusion yields as much energy as it consumes.

Fusion is markedly different from current nuclear power, which operates through splitting atoms - fission - rather than squashing them together as occurs in fusion.

"We're hoping to repeat our world record shots and extend them," Prof Cowley, who is director of the Culham Centre for Fusion Energy - which hosts Jet, told BBC News.

"Our world record was from 1997, we think we can improve on it quite considerably and get some really spectacular results. We're winding up to that and by the end of the decade we'll be doing it."

Despite its history spanning some five decades, scientists hoping to harness fusion have faced many hurdles. But it remains an attractive prospect because it can yield a near limitless supply of clean energy.

The fusion community hopes their luck could change when the multi-bn-euro Iter fusion experiment comes online in Cadarache, in the south of France, in the 2020s. And officials from Jet, based at Culham, Oxfordshire, are now in the process of signing a contract that will keep the facility running for another five years.

Jet (Joint European Torus) was the prototype for Iter and over its extended lifetime will effectively carry out a dress rehearsal for that much bigger reactor, which will aim to demonstrate the scientific viability of fusion power at scale.

Prof Cowley also hopes to use the additional five years to train up young scientists who could eventually take their expertise to Iter.

During Jet's extended run, scientists will again begin using the deuterium-tritium fuel mix needed for maximum fusion power. Until recently, scientists had been running the experiment using deuterium fuel only. 

While running the experiment in this mode allows scientists to gather valuable scientific knowledge, both deuterium and tritium will be needed to exceed the record set by the Oxfordshire facility 17 years ago.

"Jet is the only machine in the world that can handle that fuel. When you put tritium in, it reacts like crazy," said Prof Cowley.

Jet uses the same approach to fusion as Iter. This is known as magnetic confinement fusion (MCF), in which electrically charged gas called plasma is heated to millions of degrees inside a sealed tube called a "tokamak".