in the middle of the night, as the rest of America sleeps, a small group of physicists in California stand in a hushed control room. the clock steadily counts down towards zero and then, in a fraction of a second, everything happens at once
a bank of powerful lasers unleash their beams, which travel through a series of tunnels at the speed of light. bouncing back and forth, they pick up more and more energy before converging on a central sphere. inside, all 192 beams meet, focussing their power on a tiny capsule no bigger than a peppercorn. it’s all over in a matter of seconds, but in the heat and pressure at the centre of that sphere, researchers at the National Ignition Facility believe they can see the future: a world powered by the ultimate clean energy source
their goal is to show that nuclear fusion – the same ultra-efficient force which powers our sun – can be initiated with laser beams, and they’re inching closer and closer to that day. in this piece originally published in House Magazine, we caught up with Director Mike Dunne to talk about the greatest prize in physics…
Why is fusion power so exciting? The reason people have spent decades and billions of dollars on fusion research is that the prize is really quite compelling. There are no greenhouse gas emissions, it’s inherently safe as there’s only a tiny amount of fuel being used at any given time, but that tiny amount can deliver the same output as a very large coal station or a big nuclear power station. But unlike nuclear there’s no enrichment, no reprocessing and no high-level waste – so you don’t have any of those proliferation concerns.
You were working in the UK until quite recently – why did you move to the National Ignition Facility? Are they on to something? I’ve spent the last five years assembling a European consortium to develop this technology and make it a reality, and having worked through that, you get to realise what it will take to convert the dream into reality. That’s really what drew me here: this is the one place in the world that has the technology systems, the lasers big enough and operational enough to demonstrate once and for all that the science works. This is a concept that was born actually just three or four days after the laser itself was demonstrated. There was a guy here, quite a young researcher at the time, who had the idea of “hey you could actually make use of this to heat up a little bit of fuel to such a high temperature that you get fusion”.
Was he right?
With a laser, you can focus energy down to a really small spot – smaller than the width of a hair – and focus it in really short periods of time, we’re talking billionths or even trillionths of a second. When you do that you get very high power, very extreme conditions. And it turns out it’s sufficiently extreme you can mimic what goes on at the centre of the sun. So this guy had an idea fifty years ago, and it’s taken all those decades ever since to get to the point where we’ve now built a system that we strongly believe is now big enough and capable enough to achieve that dream – to get significantly more energy out than the laser itself delivers.
How close is that goal?
We’re now starting the final phase of the project, which we believe will take about a year. Of course, nothing is guaranteed, but our high expectation is that, yes, we will prove the scientific break-even point, where you get more energy out than you put in. And then of course it’s still a considerable task to take that scientific proof and configure it into a power plant. We’re now working on the basis that we know the science is laid to rest, we know that’s a done deal, so this really will mark the end of that fifty year journey. Then we set about talking to the power utility companies, and the large-scale industrial vendors – Hitachi, GE, Westinghouse, Toshiba – to convert that scientific proof into engineering reality.
Given that somebody thought of it right away, why has it taken 50 years to reach this point?
It’s a strange combination of science, sociology and politics. The idea of how you would do it was formed in 1960 and broadly that idea hasn’t changed in all of these decades. There were some difficult pieces of physics and engineering that came along that made it much harder, but it has also strongly been influenced by geopolitics and by energy prices. So we’ve seen the amount of focus that’s gone into this research ebb and flow over the decades, but we’re now at a point where the hurdle has finally been cleared, and we’re performing the experiments to figure out exactly how to activate this energy. If money were no object at the time and there was a real strategic need to drive it, could it have happened in less than fifty years? Absolutely; probably significantly.
What about other fusion projects, like the international ITER project? Is it still worth pursuing them?
No matter how wonderfully well laser fusion performs there is a finite rate at which it can grow and impact the energy economy when you’re talking about hundreds or maybe even thousands of terawatts of energy the world will need. So magnetic fusion – which is the ITER approach – advanced fission, offshore wind, solar thermal, photovoltaic, not to mention energy conservation – all of these things will be needed. We need to pursue every possible option.
+ + +
for more on the National Ignition Facility, visit http://lasers.llnl.gov
this article was originally published in House Magazine #15.