JET Fusion Experiment To Cease Operating After 31 Years
Barry Green recounts the moment in June 1983 when the JET fusion laboratory at Culham in Oxfordshire undertook its first experiment: “It felt brilliant. One thing is to work on a design, another thing is to operate it.”
For the next 31 tears, the Joint European Torus project pursued nuclear fusion and the promise of near-limitless clean energy.
But on Saturday the world’s most successful fusion experiment will wind down.
Nuclear fusion was “discovered” in the 1920s and the subsequent years of research focused on developing fusion for nuclear weapons.
In 1958, when the United States’ war research on fusion was declassified, it sent Russia, UK, Europe, Japan and the US on a race to develop fusion reactions for energy provision.
Fusion is considered the holy grail of energy production as it releases a lot of energy with almost no radioactive waste.
It is the process that powers the Sun and other stars. It works by taking pairs of light atoms and forcing them together – the opposite of nuclear fission, where heavy atoms are split apart.
The UK and the Europeans decided to pair up and from that the Joint European Torus (JET) site was born. Scientists were brought in from across the continent to Culham; Mr Green was one of them.
An Australian researcher working on plasma physics in Germany, he became an engineer working on machine design and operation. The chosen model was tokamak, which uses magnetic fields to confine the plasma – a hot, ionised gas – inside a vessel.
This plasma allows the light elements to fuse and yield energy.
It was also designed to work with a mix of deuterium-tritium – forms of hydrogen – rather than just one, which proved a crucial decision. It has been identified as the most efficient reaction for fusion reactors.
The JET team in 1977. Image: EFDA
The first experiment in the world with this fuel mix took place at JET in 1991. Subsequent experiments have achieved higher energy yields, and the site holds the world record for the most energy produced from a fusion experiment – 59 megajoules (MJ) during a five-second pulse.
Despite the records, the JET site faced many difficulties and delays, with experiments suspended for years in the mid-2000s while the internal structure was replaced, according to Fernanda Rimini, JET senior exploitation manager.
And the hope of producing enough energy to power homes remains a long way off – 59 MJ is only enough to boil about 60 kettles’ worth of water.
Joelle Mailloux is the JET science programme leader overseeing the third round of deuterium-tritium experiments which end on Saturday.
She says the key challenges they are focusing on are making the plasma more stable, spreading the power load and looking at improving materials in the reactor to withstand the conditions.
Once the experiments end, scientists will still have a lot to learn from JET.
“The decommissioning will look at analysing what has happened to the [reactor] materials and how they have changed. This will help better maintain other fusion sites,” Ms Rimini said.
One of the site’s benefiting from JET’s research will be the new International Thermonuclear Experimental Reactor (ITER) in southern France. ITER is twice the size of JET, and is the world’s largest fusion project.
It is a consortium of many countries including the EU, Russia, the US and China – but a few weeks ago the UK government confirmed the UK would not play a role.
The ITER site in France. Image: ITER
“In line with the preferences of the UK fusion sector, the UK has decided to pursue a domestic fusion energy strategy instead of associating with the EU’s Euratom programme,” the government said.
The UK government has committed to spending £650m on an alternative UK fusion programme between now and 2027. This includes a new prototype fusion energy plant in Nottinghamshire called STEP.
Paul Methven, STEP programme director at the UK Atomic Energy Agency, told the BBC:
“On endeavours like this, you need to be simultaneously really ambitious and also realistic.
We are driving pretty hard towards our first operations to be in the early 2040s.”
See more here bbc.co.uk
Header image: Physics World
Editor’s note: ITER will build on the success of JET, but it will take one, probably two, more even larger machines before a viable fusion power station can be constructed. Trying to recreate the temperatures and pressures inside a star is the most difficult engineering task we have yet undertaken. It will cost billions and take many years.
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Herb Rose
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It’s all just a waste of money. If fusion existed then it should be possible to split a helium atom into 2 deuterium atoms, releasing the binding energy and then use that energy to fuse two deuterium atoms into a helium atom releasing energy as mass is converted into energy.
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Jerry Krause
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Hi Herb,
As you described your hypothetical circular system it seems you forgot to mention the energy necessary “to split a helium atom into 2 deuterium atoms”.
Have a good day
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Herb Rose
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As a college chemistry teacher with a doctorate in chemistry, you don’t know very much about chemistry. In an exoteric reaction (atomic bomb) any energy added to initiate the reaction is released when the reaction occurs.
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Jerry Krause
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Hi Herb,-
I have a first minor in physics and I know that nuclear fission is not a chemical reaction. but a nuclear reaction as you have just described.
Have a good day
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Richard
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I went there in the 80s working on a documentary for German Tv . My only memory was the floor covered with water – me being very naive thought I was going to be vaporised as we were there when they cranked it up….. or maybe they didn’t , so long ago now .
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Wilson Sy
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I published my last paper in Nuclear Fusion (IAEA journal) in 1985 and abandoned the field, because I disagreed with betting everything on the Tokamak approach with JET and ITER sucking up all the money into engineering, when there were insufficient fundamental breakthroughs in plasma physics.
Bureaucrats (like Barry Green) took over and pretended they were running the Manhattan project or the Apollo project, which were considered triumphs of management, not science. I knew it was a fraud, unlikely to succeed unless they got very lucky, with serendipity which seems only happens with individual efforts.
Nearly 40 years and many billions of dollars later, only incremental progress had been made with Tokamaks. From JET experience, UK must have decided to try something else, while the freight train of ITER had already left the station heading nowhere. Virtually limitless, clean fusion energy is not visible unless there are fundamental changes to the allocation of resources.
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ChoppedDog
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That seems to be the crux of the Matter…hmmm?
Misallocation of resources into dead ends with much flash, smoke and other ballyhoo about. All by design.
Artificial scarcity is a bidNess plan
Fer centuries.
Wonder how civilization was even allowed to progress so far in the last 200 years… thus far. Well, now the screws turned , eh?
Depopulation rules…and you’d think that most haven’t yet wised up based upon apparent somnolence.
Could it be the sominex frequencies emitted via their Boob Toobs? Or during hours on social media where their cells emit the same?
Yep, programming via suggestible states of consciousness with brain entraining Frequencies are used to maintain the status quo….as the graveyards fill on an accelerating slope and folks wonder where their neighbors have gotten off too….leading eventually to a silent earth.
How wonderful.
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