The Guardian claims, “Nuclear Fusion – Your Time Has Come” (Jeff Forshaw), Wired claims it is, “One Step Closer to Breakeven” (attributed to ScienceNow). Well, unfortunately, “practical commercial” fusion power generation has been “perhaps as little as 20 years away” for a little over 70 years now, and that is still true, and, in my humble opinion, will still be true 40 years from now. Sooner or later, we will figure it out. It is almost certainly the primary energy source for all functions on earth and in space for our posterity. We owe it to them to work at it in good faith, but in good sense too! Fusion will not solve our current problems, nor will it help our children. We will have to work something else out for now, and perhaps our great grandchildren will see it come on line in practical ways that make societal life better. It seems to me reasonable to speculate that the first practical fusion power station will be built on the moon. I doubt anyone thinks we will have a moon base started in as little as 20 years.

The Wikipedia article covers things reasonably, but I’ll add my first hand knowledge here. My biggest gripe about fusion is all the articles perpetrate the fantasy that fusion power will be “clean and inexhaustible.” If you believe that, I have a bridge I could sell you cheap.

What is clean about a system that uses radioactive tritium? What is clean about a building, a whole freaking building, becoming radioactive? Read the wiki for the basics, but get it through your head that this ain’t clean. Safe is a relative term. I think the fusion systems I have studied should be safe enough, as long as you don’t nap in them during refurbishment cycles. Waste disposal with ITER will be a problem. JET will be a problem. They are already using remote handling for everything there. Several minutes of Google search haven’t found me any documentation, so from memory, and I’ll appreciate comments that correct me or point me to documentation, but the TFTR of Princeton Plasma Physics, while a solid overall success, ran for only several seconds of actual fusion, and when they shut it down, it was over two years before they could safely go in and decontaminate and decommission it. They ended up burying nearly the entire lab full of equipment (barge loads) in the Hanford desert. Battelle ran it if I recall, and it was done on time and under budget. Stellar for government work! (Though Battelle has a good record for such. Good on ’em.)

Now to “inexhaustible,” did I mention tritium? Oh, yes, I did. Where do we find tritium? Oh, I remember, we don’t! There isn’t any. We have to make it out of lithium via neutron radiation. So far, we do that in regular nuclear fission reactors, but it seems certain we will be able to produce it in place within the fusion reactors, well, at least notionally it will work. The engineers still have to find a way to make it practical. Since it is not hard to make tritium, no problem, right? Think again. Lithium is just a little bit rare, and we have lots of uses for it besides just burning it up in fusion reactors. So, it certainly is NOT inexhaustible. Of course, deuterium is the other fuel component, and D-D fusion is probably not much harder than D-T fusion, so maybe we can do it without the tritium, but don’t forget that deuterium is still relatively scarce, being only a tiny fraction of the hydrogen on our planet. Good thing the planet is mostly covered in water. Certainly there is plenty of deuterium, but we do have it chemically tied up in our oceans. That is an easy engineering problem, but it is still energy intensive to get it out.

My point is that fusion, like fission, like burning carbon fuels, has plenty of waste products to deal with, and it will always take lots of effort to get the active ingredients away from mother nature, and into our reactors. So, TANSTAAFL.

As to the physics, that is fairly easy. Keep experimenting, and keep the mathematicians working it, we will do it. However, then the engineers have to take over and actually design and build one of these things, and engineers go to jail when things go wrong because people die. Accordingly, engineers are predominately practical and safety minded.

First extreme engineering problem with a tokamak is extracting energy from vacuum–no, not zero point, but superheated plasma at hard-vacuum pressure levels. It will work, but it is a hard problem, which means expensive and likely requiring lots of maintenance. Second extreme problem is plasma instabilities that blast the inner walls. Same as the first problem. We will come up with good solutions with an acceptable set of compromises, but it will be costly both initially and in upkeep. The third problem is harder, and so far, intractable. We must build the system to tolerate 14 MeV neutrons. Lithium blankets may be part of the solution, as the lithium will absorb many of the neutrons and generate the tritium we need, but 14 MeV neutrons do things that seem unbelievable. The wiki article talks about it, but just know that we don’t have materials that can meet the needs of dealing with such energetic and destructive missiles. The simplified version of what happens is that in less than two years, most of your structural components will embrittle to the point that they are no safer than if they were made of plate glass. Of course, these neutrons cause the atoms to become radioactive themselves. Thus, the whole building becomes radioactive waste.

I’m getting rather rambly at this point, so I will stop. I will add that I support fusion research. We will do it some day. It will be all we do for power eventually. In the meantime, we need more fission nuclear reactors (uranium, plutonium, and thorium), and we need to keep working on our efficiencies of burning carbon fuels. Drill, dig, pipe, and burn, baby, burn.

CO2 is an essential ingredient of life. So, CO2 is a good thing. Besides, cold kills, warmer is better.