There’s a long running joke that fusion reactors are always 20 years away, something which people began saying about 60 years ago. It’s not that we get it wrong per se, more that we have a tendency to underestimate the complexity of achieving the next step, something which is usually written off as a simple piece of engineering. We’re now acutely aware of the fact that the practical aspects of running a fusion based power plant are likely going to require significant advancements in materials science and that’s if the theoretical models we have turn out to be correct. Whilst we’ve been able to fuse atoms for a long time now the end goal of fusion power generation, a self sustaining plasma, has yet to be achieved but one theoretical model recently got a jolt of hard science behind it lending a lot of credence to the whole field.
The National Ignition Facility has been dedicated to studying Inertial Containment Fusion, ostensibly because it aligns with most of their overarching goals (one of which is weapons research). Of the two main branches of fusion research, the other being Magnetic Confinement Fusion, ICF is something of a poor sibling in terms of research dollars and large scale experiments. This is not to say its claim is any less valid just that, at least in this armchair physicists understanding, its brand of fusion doesn’t lend itself particularly well to be scaled up to the power generation levels at least not with its current modelling. However NIF has announced today that, for the first time ever for any fusion experiment, their reaction released more energy than what was pumped into it; a sure sign that nuclear fusion was occurring.
It’s a pretty amazing feat and is definitely something that NIF should be proud of, however that does not take into account the total energy of the system which was several orders of magnitude higher than the energy produced at the other end. Thus for such a system to go past full unity it would need an input to output multiplier somewhere in the thousands, much more than what they’re currently achieving. Still as far as I was aware we weren’t even entirely sure if this kind of fusion was feasible, given the strict requirements on many of the parameters. Of course such challenges aren’t entirely unique to this brand of fusion but you have to wonder why after the initial burst of research into ICF things started to slow down considerably with MCF being the reigning champion for many decades now.
From what I can tell though, with my admittedly limited knowledge on the subject matter, MCF has the greatest potential to translate into powerplant scale devices much sooner than those using ICF as a base. Indeed the challenges presented to using MCF do lend themselves well to scale (although large magnetic fields always present some trifles) whereas ICF the challenges increase dramatically with scale as it becomes significantly harder to ensure the right reactions happen to sustain fusion. Of course I’m willing to be told otherwise on this as I could just be suffering from some geek lust for ITER’s sultry designs.
In any case it’s extremely exciting to see the progress that’s being made as it bodes well for a future that could be free of fossil fuels. Whilst I’d love to believe that we’re 20 years away now (and indeed ITER’s schedule puts the first DT reaction within that time frame) I’m going to need to see a few more milestones like this one to start believing it. We’re tantalizingly close however with the evidence constantly building that we’re on the right track to producing all the energy we need without having to dump untold tons of carbon back into our atmosphere.
And that’s why it’s worth spending billions of dollars on researching every possiblity for developing a sustainable fusion reactor.