4.2.6 Fusion at JET and ITER

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PROFESSOR STEVE COWLEY

What we see right now is the beginning of a shot on JET. Now, it's got up to full temperature. You don't see the hottest bit. The hottest bit of the fuel, what we call the plasma, is probably about there.

You see actually the cold bits where it's touching the wall here and here. And you saw that shaking. There was a little bit of instability there. But you also saw speckles of white. Those were neutrons hitting the wall during the shot.

That was a typical shot on JET, probably going up to a temperature of about, well, probably about 100 million degrees. Here at Culham we've done fusion. We've managed to heat up the fuels for fusion, which are called deuterium and tritium, two kinds of hydrogen, up to a temperature of 230 million degrees. And at that temperature, we got 16 megawatts of fusion power out of our reacting deuterium and tritium. We were holding it in a cage of magnetic field, so we created the conditions like the middle of a star.

This experiment that we're going to be doing in southern France, ITER, in ITER, what will happen is not only will we get fusion to happen, but the fusion will be sufficiently virulent that it'll make enough heat to keep the fuel at the temperature to react and make a self-sustained fusion burn. So what will happen in ITER is that we will get to a temperature like 250 million degrees.

It will start producing fusion. The fusion will hold it as a temperature of 250 million degrees, and we can just put in more fuel. It will burn more fuel, and you will keep going. It will sustain itself, and we call that a fusion burn.

And if we can do that, we've proved that scientifically, fusion energy is possible. And we're going to be doing that sometime in the late 2020s. It'll be a fantastic experiment.

We are in this business to make fusion the power source of the future. One day, a great deal of the planet will be powered by fusion power because it's the perfect way to make energy. We have 30 million years worth of fuel supply.

It doesn't produce long lived radioisotopes, so we don't have a nuclear waste problem. It doesn't produce carbon dioxide, so we have no global warming, and it's safe. The only problem with fusion is we have yet to really master it.

When we do master it, it will power the planet and may provide 50, 80, 90 per cent of our energy needs from fusion. So it is coming. The question is, how quickly? I'm hoping by the second half of this century, we are doing some fusion power in a commercial way.

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In the video Steve Cowley explains the experiments conducted at JET (Joint European Torus) in inducing nuclear fusion and looking to the future at the tokamak being built at ITER, (International Thermonuclear Experimental Reactor).

One of the main challenges in the development of fusion is creating a reactor that is commercially viable. At the moment, the fusion at JET can only occur for a matter of seconds. The energy achieved is about the same as that put in, to achieve the contained plasma or a little more. This means that the tokamak at JET is not commercially viable.

The successor to JET is ITER, a new tokamak that is being built in France. This should be able to produce 500 MW of fusion power.

Next, read about the National Ignition Facility (NIF).