Oct 16 2014

Lockheed Martin’s Fusion Reactor

Since I recently covered the new claims being made for the E-cat cold fusion device (which, in my opinion, is almost certainly bogus), I found it interesting that Lockheed Martin recently produced details for their research into a hot fusion reactor. Their research team, called the Skunk Works, have been working on a new design for a fusion reactor. It has two distinct advantages over the E-cat – it does not require the assumption of new physics, and it is not being promoted by a convicted con-artist.

Fusion is a type of nuclear reaction that involves combining lighter elements into heavier elements. The resulting reaction releases a significant amount of energy, and that energy can be used to generate electricity. Fusion, in fact, is the power source for stars. The immense temperature and pressure in the core of stars fuse hydrogen into helium, and then helium into heavier elements, depending on how massive the star is. The heaviest element that can be made in this fashion is iron. Elements heavier than iron require energy to fuse, and therefore you cannot get any energy out of iron from fusion or fission. Heavier elements are therefore made in the powerful explosions of supernovae.

If we could engineer a device that could produce sufficient temperature and pressure we could theoretically create nuclear fusion on earth. In fact we have already done so, in the form of hydrogen bombs. Of course, creating a massive explosion isn’t exactly useful as an energy source. The trick is creating controlled nuclear fusion without the huge explosion.

One method being worked on is using heavy hydrogen (deuterium and tritium, a proton with one and two neutrons respectively) heated to a plasma (stripped of its electrons). Plasma therefore has an electric charge, and so will respond to a magnetic field. Fusion projects like the ITER (a multi-billion dollar fusion project in France) use a configuration of magnets known as the tokamak, which is basically a torus or doughnut shape, in order to confine the hydrogen plasma. If you confine the plasma enough, the hydrogen ions will be pushed together with enough force to overcome their mutual repulsion (because the protons have a positive charge) and they can fuse together forming helium 4.

This reaction will in turn free neutrons, which don’t have a charge and therefore can escape the magnetic confinement. They will impact the containment wall, heating it up. This heat can then be used to drive a conventional turbine, generating electricity.

Lockheed Martin is now claiming they have a design for a similar fusion reactor that has an innovative arrangement of the magnetic confinement – in a spiral shape rather than a torus. Their design, they claim, has the property of creating a positive feedback loop in which, the more the plasma pushes out against the magnetic field, the stronger the field becomes, generating much greater pressure in a smaller design. Their reactor design is 1/10 the size of typical tokamak designs, such as the ITER.

They argue this will have many advantages. It will enable them, due to reduced costs, to iterate their design once a year. They claim that within five years they will achieve a working prototype. It will then take another 5 years, for a total of 10 years, to build an actual working fusion power plant. Such plants, again because of their small size, will be much cheaper to build than the ITER design, and therefore will be much more economically feasible.

They claim their fusion reactor could fit onto a large truck, and a reactor of that size could power 80,000 homes, using 50 pounds of fuel for a full year’s operation. The process does create some radioactive waste, but the half-life of this waste is only a century, compared to the thousands of years for fission waste.

Such reactors are small enough that they can be used as portable power generators for ships and even large jets.

OK – that all sounds good. I am seeing no red flags of pseudoscience. No laws of physics are being broken. No mysterious “fusion without radiation” is being claimed. They are simply claiming an innovation in the design of the magnetic containment field that allows the overall reactor size to be significantly smaller.

There are, however, two things about which I am a bit skeptical. First, the timeline they are giving is almost certainly overly optimistic. Apparently they still have some technical hurdles to overcome, and companies tend to assume (or at least pretend to their would-be investors)  that such hurdles will be mastered in due course. Sometimes, however, such hurdles prove to be stumbling blocks.

Remember the hydrogen economy? It all looked great on paper. All engineers had to do was work out some kinks and we would all be driving hydrogen cars and using them to power our homes. However, it turned out not to be so easy to design a way to store large amounts of hydrogen without too much weight in a manner that can rapidly release the hydrogen as needed and yet not explode in a car crash. They’re still working on it. We’re still waiting. We may yet see hydrogen fuel cells, but this little hurdle turned out to be a fatal flaw, at least for now.

So, how can the researchers at Lockheed Martin know for sure that five iterations will result in a working prototype? They can’t. I don’t have enough details to know what the biggest hurdles are they have to overcome, but since no one has achieved controlled fusion so far, they are likely non-trivial. The “5-10 years” may become 10-20, or 20-50. The running joke is that controlled fusion is 10 years away, and always will be. The “5-10 years” has become a running joke on the SGU because that always seems to be the claim, and yet rarely is the reality.

The other little niggle I have is that Lockheed Martin is apparently releasing details because they want to partner with other investors. Some have speculated that this is a negative commentary on their confidence in the project. If they really thought it was going to work, why would they want to spread out the risk and return?

Conclusion

The Lockheed Martin fusion reactor (unlike the E-cat) should be taken seriously. There is nothing impossible or pseudoscientific in their claims. However – they don’t have a working prototype, just the hope that they will have one in 5 years or so. I certainly hope that their claims pan out. A fusion reactor would be a huge boon to our civilization. This would be a game-changer – cheap, abundant, non-carbon-emitting energy.

But I always take claims of “5-10 years” with a massive grain of salt. The problem always is – we don’t know what we don’t know. Until you try to do something, you can’t anticipate all the possible hurdles. Also, until you try to solve a hurdle, you don’t really know how difficult it’s going to be. From what is being released, I don’t yet know what the specific technical hurdles are here, so we’ll see.

I guess we’ll just have to check back in five years.

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