- Jan 2017
Among fusion scientists, the special meaning for the phrase “fusion power” means the numerical ratio of the plasma heating power output to the plasma heating power input. In other words, it encompasses only the output/input power balance for the plasma heating subsystem. Fusion scientists have additional terms and symbols for this and similar ratios, but they are unnecessary for the scope of this article.
"Fusion power" is not a ratio, though it might be stated as a ratio. Ratios are unitless, but "fusion power" is stated in units of power, i.e., here, "megawatts." This is the core of Krivits misunderstanding, and Krivit blames scientists because their comments do not match his misunderstanding.
Fusion power is absolute, independent of input and other conditions. That is, it is what is released by the fusion of so many nuclei. All that matters for fusion power is whether or not it is measured correctly, and Krivit does not challenge the measure.
ITER’s design uses more efficient superconducting magnets that require less input power.
No power. Zero. Superconductors have literally zero resistance. The only problem is keeping the magnets cool, which is a matter of insulation. Because insulation will not be perfect, there will be some necessary power there, but it is an engineering consideration, is probably a small one compared to other considerations, and is not related to fusion power. The peak power needed to create the initial magnetic field is one-shot, for the duration of the experiment. A full study of power interactions would show that. There are other initial setup powers, such as getting the plasma current up to fusion temperature. Maintaining that may require continuous current, dependent on cooling, and, again, the plasma has a certain resistance and there will be heating, and heating is work, so this is input energy. But if the plasma reaches ignition, this can and should be shut down.
by using a magnetic field.
I would say "magnetic fields," plural, because the field structure of a tokamak is complex. It's not just the field of a single straightforward electromagnet. A plasma consists of fast-moving ions. Such will have a curved path in the presence of a magnetic field. So the magnetic fields are arranged in a tokamak such that the path curves back on itself, and runs around a torus. Other kinds of fusion reactors use electrostatic confinement or inertial confinement. (I.e., a fusible bit of fuel is impacted by high energy, perhaps from lasers, with the incoming energy balanced so that the bit of fuel is simply heated and highly compressed and fuses, it doesn't have time to expand. A form of this is what happens in a hydrogen bomb, this is inertial confinement.) Inertial confinement reactors are not continuous, they would produce energy in bursts, so much energy per "shot.")
If the plasma touched a reactor’s wall, it would instantly damage the reactor by vaporizing wall materials and terminate the reaction
Or whatever walls. They don't have to be metal. Yes, any material will vaporize at these plasma temperatures. The tiny spark, that can happen with relay contacts if there are no protective diodes, can burn the contacts, until they fail. Switches can burn out if switching an inductive load. Motor contacts, the same. This is really well within ordinary experience. The plasma used in hot fusion is hotter than ordinary lightning, I think. A "plasma disruption," it's called, will damage the containment, though it will be designed to not fail from occasional disruptions, especially if they don't strike the containment at the same place. Eventually, they will, indeed, eat away the containment. As well, if there is enough of a wall strike to disrupt the current, the reactor will shut down, entirely aside from devices installed to shut down if there is a plasma disruption. I'm not sure I'd want to be near a tokamak in a major disruption, but the most likely serious consequence would be a need to replace part of the plasma chamber wall. This, will, by the way, tend to become radioactive, due to neutron activation, another problem of hot fusion, but they are ready for that one. The tokamak should not explode, because full plasma disruption will completely and immediately shut down all fusion power.
an environment in which atomic nuclei are forced closely enough together so they can bind and undergo nuclear fusion.
At significant rate, yes, though I'm not looking up the specific numbers. Strictly, speaking, the nuclei are not "forced," that would be the action of a force on them, which is work, which would be "input energy." Rather, at fusion operating temperature, some ions have enough kinetic energy to climb the Coulomb barrier. The only force acting on the particle comes from the interaction, not from input power, and it slows the particle as it approaches. Temperature, while it may initially have been created by some force acting on the particles, is maintained by an environment unless it does work (i.e., heats the surrounding environment). This idea that fusion is "forced" is a common trope that leads to confusion. There is, in fact, a fully-accepted fusion mechanism where, experimentally, the particles are at minimal energy, i.e,. close to absolute zero.
In experimental tokamak reactors, heating is accomplished in a variety of ways that convert electricity from the grid into thermal power applied to the plasma.
Not exactly wrong. However "Heat is applied to the hydrogen isotopes" may be misleading. The tokamak is not heated, i.e., heat is not applied to it. I don't know the specific plasma creation method in tokamaks, and it might vary, but the general idea would be running a current through the plasma. At a certain voltage, the plasma will ionize (and that is the definition of plasma, it's significantly ionized, and the ionization will increase with temperature until it becomes more or less complete at very high temperatures). A common example of a plasma would be a lightning strike, or, smaller scale with much lower plasma current, an electrical spark. So we have all touched plasma.... Hopefully, though no big plasma has touched us. They are very hot, but that small spark has only a tiny energy involved -- compared to the lightning strike. Lightning strikes probably cause some level of fusion.
"Thermal power" is not applied to the plasma. Rather, the plasma is heated by increasing the current through the plasma, which has the effect of increasing the plasma temperature. That current creates thermal power, not the other way around. Again, unless there is cooling, temperature, once created, will be maintained. It's basically a form of inertia. The power necessary to maintain the temperature can be called "input power," easily, this would be continuously required for a stable plasma. It, however, depends on engineering details. If the plasma becomes self-heating, due to an adequate reaction rate, that's ignition, and no more such input power would be needed. Indeed, the backoff on input power needed to maintain plasma temperature would be a quick and easy-to-measure indication of fusion power. When it goes to zero, that's ignition, and then there arises the opposite problem: how to cool the plasma.
I don't know of any fusion reactors that don't use hydrogen isotopes for fuel. There are some theoretical proposals and I am setting aside speculations about nickel hydride LENR.
This would imply that commercial fusion power plants are not far away.
I have never seen anyone who understands fusion research who thinks that "commercial fusion power plants" are "not far away." If someone thinks that, they have not been paying attention. If someone from ITER testified to "not far away," they were lying, unless they clarify that "not far away" could easily mean more than twenty years. Krivit is correct in that the "real meaning of 'fusion power'" has nothing to do with engineering efficiency or commercial viability. It means the same as "excess energy" in LENR experiments.
The general "public" is not reading the ITER Web site, and we don't actually know how they would interpret this unless we study it, which Krivit has not done, to my knowledge. He might be correct, misunderstanding is possible, but that Web site is not necessarily designed for a totally ignorant public. It is more designed for those who might be interested and who might have some general knowledge. Is this laying blame over how to design a web site to be maximally informative?
Krivit started out by calling the ITER information a "lie." But it's not a lie, clearly, so Krivit was misleading! But Krivit must be right at all costs. So he converts his criticism to something more subtle. It's "misleading." To assess whether a communication is misleading, properly, I would need to study the effect it has on readers, and, further, communications are designed with levels of importance. Basic communication about science is often misleading, if interpreted outside of the intended message, because it can -- and probably must -- leave details out, exceptions, etc. So are the misinterpretations significant? Do they create an impression that causes harm?
This is not easy to study, but Krivit takes the easy path, he just accuses, and doesn't show evidence of what he claims, only evidence that an unidentified someone might misunderstand. Probably somewhere on the planet or on the internet, someone has misunderstood, but the issue of weight here would be public decision-makers, especially over funding. Are the scientists themselves misled? Almost certainly not, they know what "fusion power" means, in detail, and what it does not mean, and they have explained it to Krivit, over and over.
special technical meaning
It is like many scientific issues. The "special technical meaning" is actually within the ordinary range of meanings. "Fusion power" means "power from fusion." That's the "special technical meaning." Krivit thinks that it will be interpreted as "net energy deducting all related inputs," but that would be "overall net power" not "fusion power." When I sell Item X, I make a profit, typically a certain percentage. Does that mean "net profit"? Sometimes, net profit can mean profit from sales, not including overhead. However, what is my taxable profit? For that, I deduct overhead. I can call this the "net profit of the business." However, the word "profit" by itself is possibly ambiguous. Does that mean that if I use it, I am being misleading? It's possible, it depends on the usage, and most of all, it depends on whether or not the misleading interpretations are reasonable in context.
Krivit is inventing conditions for language and communication that do not reflect real communication in the real world. As he found, there are those who think that ITER can be and should be more clear, and I'll agree. Some people might well interpret "fusion energy" as Krivit has. But would this happen with decision-makers who have available experts to help them understand testimony? Not likely. Krivit, see below, has shown some congressional testimony, and claims that a question from a congressperson shows that he misunderstood. In fact, as I read it, the question showed cogency, it was a very pertinent question, and it got an honest answer. No, "ignition" has not been achieved. Krivit isn't even concerned about ignition.
However, scientifically, and at this point, what Krivit thinks "net energy" should mean is irrelevant. Does Krivit examine this? ITER is a scientific research project, not a fusion power plant designed to generate usable power, to make an overall "energy profit." Such a power plant, to be practical, must consider all expenses associated with the project, including the guy that works at the plant cafeteria and who uses electrical appliances which use power, included in what the plant consumes. At this point, fusion engineering is not at the point where study of that overall impact would be anything more than a waste of time and money. ITER is designed and funded to increase engineering knowledge around maintaining a plasma at fusion conditions.
misled the public and elected officials.
Krivit has not demonstrated, so far, that anyone was actually misled, other than him. Further, he hasn't actually shown that he, himself, was misled; rather he has identified a possible misunderstanding. Did he ever write something that shows he was misled? At least that would show one misled person! Krivit is generally searching for "lies" or "deception." Seek and ye shall find. But it may be meaningless.
The two images above
This is brief polemic, about a "potential source." They are not wrong. How much information does Krivit expect in two sentences? "Harnessing fusion's power" is a somewhat misleading goal stated for ITER. The goal is to study plasma behavior and control, which is an aspect of harnessing fusion power. One might think that "harnessing" was a goal for ITER, to actually produce net energy overall. It's not, and it is obviously not the goal, ITER is not engineered for that. ITER may demonstrate progress in what it could take to "harness" fusion energy.
many fusion scientists
"Many fusion scientists" is vague and Krivit has no real evidence for this, it is an imagination. It might or might not be true and is, in fact, irrelevant to the issue here, unless those scientists believe in Krivit's imagined implication re "net energy." I have never seen this misunderstanding from a scientist. What I have seen is explanations that were incomplete, that did not address the issue Krivit raises.
500 MW of fusion power for 50 MW of input power (a power amplification of 10)
what is "input power"? Does it mean the total power usage of the entire research facility -- because this is a research facility, not a power plant (No.) -- and is this peak power (Yes, probably) or continuous power (Unlikely, but they would hope to get there)? "Net energy" probably means coming close to satisfying the Lawson Criterion. It is not yet, necessarily, to be "net energy," from the social and practical point of view. ITER is not designed to be a net energy producer from the overall full-social sense, where one would look at every energy input to the process, as a real and practical application.
JET consumed 684 million Watts of electrical power.
No. It converted 700 MW of system power (this is not the real figure, by the way, but using it....) into heat and an additional 16 MW of fusion power for a total heating power of 716 MW. "684 MW" is a completely meaningless figure.
their record-setting laboratory experiments have produced megawatts (millions of Watts) of “fusion power.”
the statement, using ordinary language, is true. Peak power released by fusion ("fusion power") was 16 MW. It was a record, a difficult accomplishment, a result of perhaps forty years of fusion efforts. Krivit wants to make this mean something that it does not mean. That something is misleading. He is apparently creating the problem, as far as what he has shown, so far.
may have been sold
"May have" or "was"? Further, was this intentional? Presumably the public and especially elected officials will have their own experts to analyze information, looking for possible bias. Could the information presented by ITER be biased in some way? Wouldn't it be utterly astonishing if it were not? Human institutions involve human beings, who have opinions and agendas and interests. It takes high training to avoid this, and it is never perfectly avoided. What we see does depend to some degree on what we seek to see.
an excellent replacement
Probably not "excellent," but if we are comparing it with, say, burning lots of coal (greenhouse gases), or solar power (unless it is satellite solar power, requires massive energy storage), or fission power (creates dangerous waste), it may be "better." We cannot yet actually compare it with LENR, only with ideas about LENR based on projections from what we know. Hot fusion is facing severe engineering difficulties, but the science is well-known. LENR is not understood, in spite of what a few may claim (such as Krivit and his obvious sponsor, Lewis Larsen of Lattice Energy, co-author for and most active promoter of "Widom-Larsen theory.")