A Post for the New Year: Do we Still have a Chance to Avoid Collapse?

The article below is an attempt to propose (once more) to the general public the main results of "The Limits to Growth" study of 1972. It is a brief text that appeared in a major Italian newspaper (Il Fatto Quotidiano) on Dec 30, 2022. The limits of length of these articles are, typically, under 800 words, so I had to be extremely synthetic (for an in-depth assessment, see our recent book, "Limits and Beyond"). Mainly, I was curious to see how people would react to my rather blunt statements. 

One good thing about "Il Fatto" is that there is no censorship on comments (except for extreme cases) and so people are free to express themselves as they like, including insulting the authors of the articles ("Liar!" "Idiot!" "Snake Oil Seller!"). As I said in a previous post, I listen to everyone and I trust no one. So, even the most rabid and insulting comments are a chance to grok something. For this article, as for many others on "Il Fatto," I received personal attacks because I am too catastrophistic, and also because I am not catastrophistic enough. Some comments are nearly completely incomprehensible and, as usual, people tend to take refuge in impossible nuclear dreams. But I received also a few comments from people who seem to have understood how things stand. We'll see how the debate evolves, for the time being, I am reporting a few translated comments after the main text. 

Happy new year, everybody! 

2022 has been a difficult year for climate and energy. But there is still some hope

From "Il Fatto Quotidiano" 

Di Ugo Bardi -30 Dec 2022

The year 2022 was a year of great transformation and great difficulty. To assess what lies ahead in the coming year, we might start with the fact that 2022 was the 50th anniversary of the publication of the 1972 study The Limits to Growth. It was not a prophecy, but an analysis of current trends. It said that, if nothing changed, we could expect the beginning of an irreversible decline of the world economy in the first decades of the 21st century. The result of the combined effect of natural resource depletion and pollution.

These are phenomena that occur over a multi-decade span, but the events of 2022 are in line with the trajectory already outlined 50 years ago. Today, the "World System" looks like one of those old cars that loses parts all over the place, consumes fuel like a truck, and pollutes like a coal-fired power plant. In addition, the mechanics not only do not know how to fix it, but they spend their time fighting each other.

We are in trouble on all fronts, first and foremost with fossil fuels. After the Covid-19 crisis of 2020, production showed some recovery, but only a partial one. As for natural gas, Europeans had become accustomed to cheap Russian gas, and this year they got a nasty surprise. Replacing Russian gas will not be easy, and surely the costs of liquefied natural gas are much higher. Not to mention the costs of the infrastructure needed to handle it. And let's say nothing about coal, which is expensive, impractical, and polluting. As for nuclear power, the costs are truly out of this world. It is discussed seriously only where dictatorial governments can afford to embark on expensive and uncertain ventures.

Then there is agriculture, for which fossil fuels are needed for fertilizer and all production operations. At present, the world's agricultural production is fairly stable, but prices are rising everywhere. This is putting the poorest in dire straits. According to FAO data, we are close to having one billion hungry people, and the numbers are growing. In parallel, the growth of the world population has seen a remarkable slowdown. Globally, it is still growing but, if current trends continue, in a few years we may see the beginning of an irreversible decline. On this point, The Limits to Growth was even too optimistic, proposing that the human population could continue growing despite the economic downturn.

About climate, The Limits to Growth saw climate change (part of the general pollution problem) playing a major role only after the beginning of the collapse of the economic system. It may be that, even in this area, the analysis was correct. For the time being, climate change caused regional disasters, rather than global catastrophes. That does not mean we can ignore the problem. The concentration of greenhouse gases in the atmosphere continues to increase and, with it, the earth's temperature. At the same time, no one seems to care about doing anything serious about it anymore, as seen with this year's Cop27.

In short, we are in bad shape. It certainly seems that The Limits to Growth was even more prophetic than its creators themselves expected.

But there are also positive findings that the 50-year-old study could not account for. One is the discovery that the Earth's ecosystem can have an important cooling effect on climate. Not that this will get us off the hook but, if we treat both forests and marine ecosystems better, we can do something good to reduce the effects of greenhouse gases. Another positive factor is the disruptive growth of renewable energy, which today has such low prices that it has no competitors.

If we can get a few decades of peace, perhaps even just one or two, we can expect solar and wind power to replace most fossil fuel energy production. By coupling renewables with higher efficiency of use, we could greatly reduce the problems of both energy availability and emissions.

Can we do it? Maybe we can. And if we work at it, the most pessimistic scenarios of the Limits to Growth will not come true. So happy new year to all!

____________________________________________________________

Some examples of comments (translated from Italian)

From "Diomedes01" (insults)

The usual idiocies of the end of the year! The author is not an ecologist but an anti-nuclear and is willing to write baloney. The IEA wrote that the most economical energy ever is nuclear energy in any way you count! Instead the author says it is the most expensive when the most expensive are renewables that are made competitive by excluding from costs more or less everything! At the end of the day for the author better fossil and gas than nuclear and we talk about green transition! Ha ha ha.

From "Cortisol0" (nearly completely incomprehensible)

... If we are to have any hope people like you must be relieved of the social role you have, as you of how to solve this crisis from innate human behaviors incompatible with having developed science and technology that combined in tools=machines allow you to release and apply monstrous amounts of energy modifying both the natural energy flow, and the ecosystem, you will never admit it, as it is to develop precisely science and technology claiming endless growth, that the current environmental disaster is being produced and it is only possible with your PRIMARY contribution and denying that it is the fault of this combined conjugate because you are the most guilty of all and once it emerged you would be immediately prosecuted popularly for it and your career and life would be irremediably ruined, while the state and its power demand more and more science and power for weapons and social control, so you pretend to seek a solution when the solution as the initial act is to eliminate this dynamic you are part of with the state.

From "MarcoMx" (good understanding of the matter)

"One is the discovery that the Earth's ecosystem can have an important cooling effect on climate." I'll bet a coffee on that. The planet will not watch unresponsive to our stupidity, it will find a way to cool itself, plants and greenery we are late in defending will grow them themselves. If, however, in the equation we were able to bring the war factor, including armaments and related costs, to zero, or almost zero, the equation would become solvable without much difficulty. We would have much more resources for everything, hunger, energy transition, and pollution. By the way, the popularizers of the climate crisis almost never talk about the burden of weapons and wars (to think the worst...). But one only has to look at the figures to see that it is decisive, over $2 TRILLION each year.  If we fail to do this, well then all the consequent problems we deserve, including eventual extinction. In that case, we would be left with billions of cell phones full of the latest selfies ... the aliens who find them after thousands of years will come to the inevitable conclusion, "What a cocksucker civilization."

The Dark Side of Nuclear Fusion: A New Generation of Weapons of Mass Destruction?

In December 1938 the atomic era was born in Otto Hahns beakers at the Kaiser-Wilhelm-Gesellschaft zur Förderung der Wissenschaften in Berlin, now Max Planck Institutes, where fission of uranium and thorium was discovered. In the image, the discovery as shown in Walt Disney's movie "Our Friend, the Atom" in 1956

This is a guest post by Giuseppe ("Pepi") Cima, retired nuclear researcher. It summarizes a number of facts that are known, in principle, but largely hidden from the public. Basically, research on nuclear fusion, sometimes touted as a benign technology able to produce energy "too cheap to meter," is often financed because of its military applications. The search is for an "inertial confinement device," that would detonate without the need for a trigger in the form of a conventional fission bomb. These devices could cover a range of destructive power that could go from tactical warheads to planet-bursting weapons. Fortunately, we are not there, yet, but Cima correctly notes how the current situation is similar to the way things were in the 1930s, when a group of bright scientists started working on nuclear chain reactions with the objective of unleashing the awesome power of nuclear fission. At the time, it was an enormously difficult challenge, but the task could be accomplished by means of the lavish financial support provided by the psychopathic criminals who were in power at the time, who were motivated by the perspective of developing an enormously powerful weapon. Today, we do not lack money for military research, nor do we lack criminals at the top, so we can only hope that the task of turning nuclear fusion into even more powerful weapons of mass destruction will turn out to be unfeasible. Unfortunately, we can't be sure about that and, if they are making good progress at that, surely they won't tell us. (U.B.)

By Giuseppe Cima

In February 1939, Leo Szilard, who had already thought of the chain reactions for energy in 1934, conceived the possibility of a bomb of extraordinary power. In September 1939 Szilard, with Eugene Wigner and Edward Teller, the soul of the H-bomb and the only one with a driving license, all Hungarians, went to see Albert Einstein who was on vacation on the New Jersey shore: it was already clear what to be afraid of. Szilard knew Einstein well from the Berlin years; they had jointly patented a new type of refrigerator. This time the idea was a device that could destroy an entire city in one blast. Together, they wrote a letter to President Roosevelt and almost nothing happened for about two years.

I can visualize the three Hungarians with a strong European accent, in Washington, trying to convince the Uranium Committee: a general, an admiral, and some mature scientists. "We canna make a little bomba and it will blow up a whola city." How could they believe it? But, in August 1945, six years later, nuclear power had changed the world, quickly ended world war two, and started an industry the size of the automotive one.

After a few years, Otto Hahn became a fervent opponent of the use of atomic energy for military purposes. Even before Hiroshima, Szilard, one of the most brilliant minds of the time, was ousted from anything to do with nuclear power, he devoted himself full-time to biology and in 1962 started the Council for a Livable World, an organization dedicated to the elimination of nuclear arsenals. In a 1947 issue of The Atlantic, Einstein claimed that only the United Nations should have atomic weapons at their disposal, as a deterrent to new wars. 

Why should we recall these episodes now? Because something similar is occurring today with nuclear fusion.


The essential fusion

Today, most people probably have some idea of what nuclear fusion is, even the Italian prime minister, Mr. Mario Draghi, spoke about it at a recent parliament session. Although energy can be produced by splitting uranium nuclei in two, it can also be produced by fusing light atomic nuclei. We have all been taught that this is the way the sun works and it has been repeated to boredom by people with a superficial knowledge of these processes, such as the Italian minister for the ecological transition Roberto Cingolani. But not everyone knows that if helium could be readily generated by two hydrogen atoms, our star, made of hydrogen, would have exploded billions of years ago in a giant cosmic bang. Fortunately, the fusion of hydrogen involves a "weak" reaction and is so slow and so unlikely that, even with the extraordinary conditions of the sun's core, the energy density produced by the reaction is about the same as that of a stack of decomposing manure, the kind we see smoking in the fields in winter.  To radiate the low-level energy produced in its giant core the sun, almost a million kilometers in diameter, must shine at twice the temperature of a lightbulb filament when is on.

To do something useful on Earth by means of nuclear fusion, one can't use hydrogen but needs two of its rare isotopes, deuterium and tritium, not by chance the ingredients of H bombs. The promoters of fusion for pacific purposes don't mention bombs, but this is precisely what I want to talk about, the analogies between fusion now and what happened in the 1930s and 1940s.


Peaceful use?

Reading what was written by the scientists who worked in nuclear fusion in the early years of the "atomic age" shows that the development of an energy source for peaceful use, energy "too cheap to meter", is what motivated them more than anything else. The same arguments were brought forward by Claudio Descalzi, CEO of ENI, a major investor in fusion, addressing the Italian Parliamentary Committee for the Security of the Republic (COPASIR) in a hearing of December 9th 2021: fusion will offer humanity large quantities of energy of a safe, clean and virtually inexhaustible kind.

Wishful thinking: with regard to "inexhaustible," we cannot do anything in fusion without tritium (an isotope of hydrogen) which is nonexistent on this planet and most of the theoretical predictions, no experiments to date, say that magnetic confinement, the main hope of fusion, will not self-fertilize. Speaking of "clean" energy, Paola Batistoni, head of ENEA's Fusion Energy Development Division, at reactor shutdown envisages the production of hundreds of thousands of tons of materials unapproachable by humans for hundreds of years.

However, the problem I am worried about here is a military problem, mostly ignored, even by COPASIR, the Parliamentary Committee for the Security of the Republic. There are many reasons to worry about nuclear fusion: the huge amount of magnetic energy in the reactor can cause explosions equivalent to hundreds of kilograms of TNT, resulting in the release of tritium, a very radioactive and difficult to contain gas. On top of it, with the neutrons of nuclear fusion, it is possible to breed fissile materials. But the risks that seem to me most worrisome in the long run will come from new weapons, never seen before.


New Weapons

To better understand this issue, let's review how classical thermonuclear weapons work, the 70-year-old ones. Their exact characteristics are not in the public domain but Wikipedia describes them in sufficient detail. For a more complete introduction, I recommend the highly readable books by Richard Rhodes. There exist today "simple" fission bombs, which use only fissile reactions to generate energy, and "thermonuclear" bombs, which use both fission and fusion for that purpose. Thermonuclear bombs are an example of inertial confinement fusion (ICF), where everything happens so quickly that all the energy is released before the reacting matter has the time to disperse.

The New York Times recently announced advances in the field of inertial fusion at the Lawrence Livermore National Lab in California with an article reporting important findings from NIF, the National Ignition Facility. What really happened was that the 192 most powerful lasers in the world, simultaneously shining the inner walls of a gold capsule of a few centimeters, vaporize it to millions of degrees. The X-rays emitted by this gold plasma in turn heat the surface of a 3 mm fusion fuel sphere which, imploding, reaches ignition. Ignition means that the fusion reactions are self-sustaining until the fuel is used up. As described in the article, without an atom bomb trigger, a few kilograms worth of TNT thermonuclear explosion occurs as in the conceptually analogous, but vastly more powerful, H-bomb of Teller and Ulam from the fifties. 

Fig. 1 Diagram of the Teller-Ulam thermonuclear device. The explosion is contained within a cavity, technically a "hohlraum", in analogy to the gold capsule of the NIF experiment but hundreds of times bigger.

We don't have to worry about these recent results too much, for now, NIF still needs three football fields of equipment to work, nothing which one could place at the tip of a rocket or drop from the belly of an airplane, but its miniaturization is the next step.

In fusion, military and civilian, particles must collide with an energy of the order of 10 keV, ten thousand electron-volts, the 100 million degrees mentioned everywhere speaking of fusion. Regarding the necessary fuel ingredients, deuterium is abundant, stable, and easily available. Tritium on the other hand, with an average life of 10 years, can't be found in nature and only a few fission reactors can produce it in small quantities. The world reserves are around 50 kg, barely enough for scientific experiments, and it's thousands of times more expensive than gold. The fusion bombs solved the tritium procurement issue by transmuting lithium 6, the fusion fuel of Fig. 1, instantaneously, by means of fission neutrons. In civilian fusion, instead, the possibility of extracting enough tritium from lithium is far from obvious. It is one of the important issues expected to be demonstrated by ITER, a gigantic TOKAMAK, the most promising incarnation of magnetic fusion, under construction in the south of France with money from all over the world but mainly from the European community. The Russians, who invented it, and the Americans, the ones with most of the experience in the field, are skeptical partners contributing less money than Italy. The NIF inertial fusion experiment, instead, is financed by the Pentagon with billions of dollars, the most expensive fusion investment to reach ignition. 

Along the lines of NIF, there is also a French program, another country armed with nuclear weapopns. CEA, the Commissariat à l'Energie Atomique, Direction des Application Militaires, finances near Bordeaux the Laser Méga-Joule (LMJ), three billion euros and operational since October 2014. Investments like these show the level of military interest in fission-free fusion and so far they are the only ones who have achieved self-sustaining reactions.


Private enterprises

In the private field, First Light Fusion, a British company, has already invested tens of millions to carry out inertial fusion by striking a solid fuel target with a tennis ball size bullet. The experimental results consist, for now, of just a handful of neutrons. The amount of heat generated is, so far, undetectable, but the energy of the neutrons, 2.45 MeV, corresponds to the fusion of deuterium, the material of the target. I cited First Light Fusion to indicate that there is interest in inertial fusion even in private companies outside nuclear weapons national laboratories. Marvel Fusion, based in Bavaria, is another private enterprise claiming a new way to inertial confinement ignition.

For those wondering if the 12 orders of magnitude of difference for the density of the fuel needed in comparison to that of solid matter, and that of TOKAMAK, the one of a good lab vacuum, hide alternative methods to carry out nuclear fusion for peaceful and military purposes, the answer is certainly positive. Until now, in academia, before the advent of entrepreneurs' fusion, no proposal seemed attractive enough to be seriously pursued experimentally. The panorama could change in years to come, the proposal of General Fusion, Jeff Bezos's company to be clear, is of this type: short pulses at intermediate density. One wonders if the CEO of Amazon is aware of sponsoring research with possible military applications.


Experiments

The idea of ​​triggering fusion in a deuterium-tritium target by concentrating laser radiation, or conventional explosives, has long fascinated those who see it as a potentially unlimited source of energy and also those who consider it an effective and devastating weapon. At the Frascati laboratories of CNEN, the Comitato Nazionale per l'Energia Nucleare, now ENEA, Energia Nucleare e Energie Alternative, we find examples of experimentation of both methods in the 70s, see "50 years of research on fusion in Italy" by Paola Batistoni.

According to some sources, the idea of ​​triggering fusion with conventional explosives, as in the Frascati MAFIN and MIRAPI experiments of the mentioned CNEN review report, was seriously considered by Russian weapon scientists in the early 1950s and vigorously pursued at the Lawrence Livermore Laboratory during the 1958-61, the years of a moratorium on nuclear testing, as part of a program ironically titled "DOVE".

According to Sam Cohen, who worked at the Manhattan Project, DOVE failed in its goal of developing a neutron bomb "for technical reasons, which I am not free to discuss." But Ray Kidder, formerly at Lawrence Livermore, says the US lost interest in the DOVE program when testing resumed because "the fission trigger was a lot easier". It didn't all end there though, it is instructive to read now an article that appeared in the NYT in 1988, which describes a nuclear experiment carried out in order to verify the feasibility of an inertial fusion explosion not triggered by fission, such as Livermore's NIF. In addition to showing the unequivocal military interest in these initiatives, the article gives an idea of ​​the complexity, and slow pace, of their development. Nevertheless, the initiatives of the 80s seem to be bearing fruit now.

Modern nuclear devices are "boosted", they use fusion to enhance their yield and reduce their cost but the bulk of the explosive power still originates from the surrounding fissile material, not from fusion. However, there are devices where energy originates almost exclusively from fusion reactions such as the mother of all bombs, the Russian Tzar Bomb. With its 50 megatons, a multi-stage H, the addition of a tamper of fissile material would have greatly enhanced its yield but it was preferred to keep it “clean”.

It is important to underline that the H component of a thermonuclear device, unlike fissile explosives, contributes little to long-term environmental radioactivity. Uncovering the secrets of the ICF could indicate how to annihilate the enemy while limiting permanent environmental damage. It is the same reason why civilian fusion is claimed to be more attractive than fission: the final products, mostly helium, are much less radioactive than the heavy elements characteristic of fission ashes. As mentioned earlier, radioactivity nonetheless jeopardizes the usefulness of civilian fusion in other ways: a heavy neutron flux reduces the already precarious reliability of the reactor, and radioactivity protection greatly increases its cost.

Despite the rhetoric of some press advertising, the relevance of ICF for energy production is minimal for many reasons: first of all, as in the case of NIF, the primary energy, the supply power of all devices involved, is hundreds of times higher than the thermal energy produced by the reactions, the quasi-breakeven reported refers to the energy of the laser light alone. Even more importantly the micro-explosion repetition rate and the reliability necessary in a power plant constitute insurmountable obstacles.


Where do we stand?

Back to ICF, the Lawrence Livermore National Lab's NIF experiment is funded by the Department Of Defense aiming at new weapons while complying with yield limits imposed by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The Question of Pure Fusion Explosions Under the CTBT, Science & Global Security, 1998, Volume 7. pp.129-150 explains why we should be concerned about pure fusion weapons presently under investigation.

With nuclear fusion, we are witnessing a situation similar to what appeared clear to many of the scientists who participated in the development of weapons at the time of Hiroshima and Nagasaki: nuclear energy is frighteningly dangerous while potentially useful for producing energy and as a war deterrent.

With fusion, the balance between weapons and peaceful uses seems to be even more questionable, making further developments harder to justify. Fusion weapons, which will arrive earlier than reactors, are potentially more devastating than fission with a wider range to both higher and lower yields. Low-power devices, while remaining very destructive, would not carry a strong deterrent power, and the super high-power ones, hundreds and thousands of megatons, would have catastrophic consequences on a planetary level. On the other hand, electricity production by fusion seems now less and less likely to work out, economically less attractive than the already uninviting fission.

The wind and photovoltaic revolution, rendering the already proven nuclear fission obsolete despite the urgency of decarbonization, are making fusion unappealing even before it's proven to work. At the same time, possible military applications should discourage even the investigation of fusion tritium technologies. At the very least, new research regulations are needed.


It's a collective choice

Is "science" unstoppable in this instance?

First of all, I would characterize these developments as a purely technological development than a scientific one. We are talking of applications without general interest, not a frontier of science. Fusion is a "nuclear chemistry" with potentially aberrant applications, in analogy to other fields which are investigated in strict isolation. Fortunately, fusion is an economically very demanding technology, impossible to develop in a home garage. Working on fusion can be, at least for now, only a collective choice that reminds the story of the atomic bomb at the end of the 30s, but at a more advanced stage of development than when Szilard involved Einstein to reach Roosevelt. Is the genius is about to come out of the lamp?

Author's CV - I researched nuclear fusion in labs and universities in Europe and the US, publishing around 100 peer-reviewed papers in this field. After losing faith that a deconstructionist approach to fusion could yield better reactor performances than already indicated by present day experiments I started an industrial automation company in Texas. I have now retired in Venezia, Italy, where I pursue my lifetime interests: environmental protection, energy conservation, teaching technology and science, and, more recently, mechanical watches. Giuseppe Cima

Previously published in Italian on Scenari per il Domani, sep 14 2022

The Tortuous Way to Nuclear Fusion

Giuseppe Cima discusses the real perspectives of fusion energy

By Giuseppe Cima

Newspapers make you think that nuclear fusion for electricity production is within reach and that, unlike fission, it is cheaper, cleaner, and safer. Okay, it's not online yet, it is argued, but it's up to us how fast it will supply useful energy. Things appear more complicated than that as soon as we take a look at the extraordinary variety of methods adopted by all the initiatives proposed.

Some use fuel from nuclear warheads, such as Commonwealth Fusion Systems, of which ENI is a shareholder. Others use the boron-proton reaction, such as the TAE, financed by ENEL, Tokamak Energy promotes magnetic confinement, and First Light Fusion of Oxford has been inspired by the "claw" of Alpheus heterochaelis, the gun shrimp claw. There are about thirty companies in this market and just as many, very different, methods. For the most part, these methods have been already studied, and discarded, by the academic community, and yet the industry has not decided which path to follow. This confusion indicates how distant the goal is. Let's revisit the story of fusion and the origin of this explosion of promises.

The inspiration for nuclear fusion came from looking at the sky, it originated with the mystery of the energy that powers the stars. At first they thought of gravity, a non-trivial idea for a body as large as the Sun. Jupiter, for example, a gaseous planet, has a surface temperature twice that of the Earth, powered by gravity while the planet shrinks of a few millimeters per year. Gravity was also Lord Kelvin's hypothesis for the Sun's power during a famous meeting of the Royal Society on January 21, 1887. The surface temperature of the Sun made him deduce that our star had been shining for about twelve million years, much longer than the Bible states.

William Thomson, 1st Baron Kelvin


Paleontologists were upset, gravitational energy doesn't fit the data, fossils on Earth are evidence of a Sun that has been shining for at least several hundred million years. The discussion remained on hold for a while until Arthur Eddington in the 1920s hypothesized that the heat originates from the fusion of hydrogen into helium. It was already known that helium weighs significantly less than four hydrogen atoms and we now know that this difference accounts for the solar radiation. But something was still wrong, the internal temperature seemed too low to support the relevant nuclear reactions. A few years later, new hypotheses emerged on the decay of hydrogen into helium and in Cambridge, in the 1930s the first accelerators experimentally proved the existence of fusion reactions. In the 1940s some illustrious veterans of Los Alamos - the physicists who worked on the atomic bomb - studied the problem, correctly identifying the main reactions and stellar nucleosynthesis was satisfactorily understood. Recent observations of solar neutrinos confirm the hypotheses of the 1940s: fusion of ordinary hydrogen, the same of H2O, provides all the energy radiated by the Sun.

What does this story have to do with the nuclear fusion that is now being talked about so much in the newspapers? Almost nothing. It's surprising but the stars, thanks to their enormous size and mind-blowing pressure, shine at 5,000 degrees while burning exasperatingly slowly, with the power intensity (ratio of power to mass) of a compost pile. If not, they would rapidly explode and disappear. We, on Earth, with our energy range of ten kilowatts per capita, would not know what to do with stellar fusion which has the power of our basal metabolic rate. What could be used on Earth comes from another branch of science: weapons.

After the development of fission nuclear devices in World War 2, we also developed the fusion of light atoms and in the 1950s, in order to overcome the power limits of fission, the first fusion bombs were developed in secrecy. This time hydrogen, the main component of the Sun and of the water molecule, is not the fuel but two of its rare isotopes are. From these isotopes, deuterium and tritium, come the most powerful weapons, such as the mother of all bombs, the Soviet 40 megaton Tsar Bomb (hopefully none is left in stock) that uses a conventional fission bomb to trigger the hydrogen fusion. Cheaper fission weapons, the so called boosted bombs, use the same principle. Now we know what's the ideal fuel for applications of fusion, the one that burns most easily, a mixture of deuterium and tritium, (DT). Almost immediately people started to think of using fusion for electricity production and started research programs, unclassified, from the 1960s.

Magnetic Confinement Fusion, MCF, turned out to be the method that attracted the favor of those looking for continuous combustion of deuterium-tritium and until now, it has remained the preferred way. The most popular MCF device is called TOKAMAK, a Russian acronym attributed to its inventors, Igor Tamm and Andrei Sakharov, (the latter is the same person who developed the H-bomb and civil rights fame- the world of physicists 50 years ago was smaller.)

Fusion is closely linked to thermonuclear weapons: they have in common the raw material, sophisticated and rare components - deuterium and tritium - certainly not just seawater, as we often hear. Deuterium, about .02 % of hydrogen, is readily available and costs only $ 4 per gram. Tritium, on the other hand, is not present in nature, has an average life of ten years, and is produced only by CANDU nuclear reactors. Stocks of tritium in the world consist of about 50 kg accumulated over the years, barely enough for future experiments and it is a thousand times more expensive than gold.

The weapons solved the tritium scarcity by creating it from an isotope of lithium bombarded by their own neutrons. It is the same lithium that is used for modern cell phone batteries and electric cars, but fusion would burn it in such modest quantities as not to increase its scarcity. Nevertheless, for civilian applications of fusion, the possibility of extracting enough tritium from lithium is far from obvious, the theoretical predictions are not good, experiments have never been made, and it is one of the most relevant results we expect from ITER, a gigantic magnetic confinement experiment whose construction in southern France will produce results hopefully in a couple of decades.

It must also be borne in mind that, if fusion ever proved possible, these 1 GW reactors would have to line up by the thousands to supply themselves with the tritium they need to contribute to the 16 TW global energy hunger.

It is already clear that three common statements about fusion, namely that it is near, cheap, and safe, are premature at best. The fuel is not seawater but it is hard to find and is the same stuff as most nuclear devices use, those same weapons which would be so dangerous in the wrong hands.

For now, there are still no fusion weapons, currently, they need a fission trigger, but explosions of pure deuterium-tritium would be very attractive because, at equal destructive power, they are "cleaner", with less radioactive leftover than the plutonium ones. It's no coincidence that the second-largest fusion project in the world, nearly $ 10 billion in funding, the Lawrence Livermore National Laboratory's NIF in California, has been arranged by the Department of Defense and not by the Department of Energy. NIF has shown it can detonate millimeter-diameter deuterium-tritium capsules triggered by the world's largest laser, the size of three football fields. For now they are not explosions of a kiloton, a thousand tons of TNT, but of a milliton, a thousandth of a ton, a stick of TNT. However, we know that, as in all detonations, the difficult operation is to trigger them. NIF is also promoted as a method suitable for a continuous energy production reactor. I leave it to you to imagine how realistic it would be to string hundreds of explosions per minute with sub-millimeter precision for decades, explosions that individually already stress to the limit a steel vacuum vessel the size of a gymnasium.

Inertial Confinement Fusion, ICF, of which the NIF is the best-known example, is not the only alternative to ITER's magnetic confinement, MCF. Between the very high fuel densities of the ICF, hundreds of times the solid, and the very low densities of the MCF, tens of thousands less dense than our atmosphere, intermediate densities could be employed by fusion by exploiting the magnetic field of MCF and the fast compression of ICF. There have been a few attempts in this direction in the history of fusion but at Colleferro, Italy, in the CNEN laboratories, in the 1960s, experiments were carried out with promising results. High-intensity sources of fusion neutrons were produced by imploding magnetized plasmas with the aid of conventional chemical explosives. The reason for the limited popularity of this method as a potential energy source is found again in how difficult it would be to produce high-frequency explosions, for years and years, as would be required in a reactor. Low-powered, low fallout, tactical bombs immediately come to mind as a possibility for the intermediate-density method. From the 1960s onwards there has been little mention of medium density fusion, until a few years ago when a small private initiative was born in Canada: General Fusion (GF).

GF offers something similar to those earlier Colleferro experiments, but with mechanical pistons instead of explosives. According to General Fusion, the new technique would allow the combustion of deuterium-tritium to be repeated cyclically at a potentially attractive rate and cost. In Colleferro, using explosives, they had not even reached ignition and no one would have noted General Fusion, one of the dozens of private fusion initiatives, were it not that Jeff Bezos, of Amazon fame, decided to invest up to two billion dollars in this venture. Regarding the General Fusion proposal, it is a real shame we can't seek the opinion of the CNEN, now ENEA, researchers who carried out the Colleferro experiments. Unfortunately, the signatories of the publications of those times are no longer with us. This observation reminds us of the very long development times of fusion experiments, a crucial problem in this field. Almost equally interesting it would be to ask Jeff Bezos if he ever noticed that the devices whose development he finances could also help to invent new nuclear armaments.

Military applications of civil fusion should certainly be a major drawback, but the inevitable radioactive activation of fusion reactor structures is even more so. Unlike the solid core of a fission reactor, the thin fuel of a magnetic confinement fusion reactor is transparent to the neutrons it produces and they are stopped only by the first solid wall they encounter. Even ITER, just an experiment, will generate tens of thousands of tons of radioactive material whose disposal would certainly contribute to the cost of the kilowatt-hour of a conceptually similar reactor.

The price of energy will ultimately decide the development of nuclear fusion. The comparison, for now, is with natural gas, which produces electricity in the US at the unbeatable cost of 2 ¢ per kilowatt-hour and with the new renewables, wind and solar, now only three or four times more expensive than gas and, in some cases, even less expensive. Nuclear plants are too large to enjoy the economies of scale of mass-produced gas turbines, solar panels and wind turbines. This feature penalizes fusion enormously and there are solid physical and safety reasons to make us think that this situation will not change. Fusion is now too far behind in its industrial development to be able to participate in decarbonization in this century, which is why it must be pursued with a very long-term perspective and kept away from financial speculation.

Giuseppe Cima, I researched nuclear fusion in labs and universities in Europe and the US : Culham labs in UK, ENEA in Frascati, CNR in Milan, University of Texas in Austin and published more than 70 peer reviewed papers in this field. After loosing faith that a deconstructionist approach to fusion could yield better reactor performances than already indicated by present day experiments I started an industrial automation company in Texas. I have now retired in Venezia, Italy, where I pursue my lifetime interests: environmental protection, energy conservation, teaching technology and science, the physics of mechanical horology.

Star Parasites: Carbon-Based Life and the Future of the Universe

  The universe is enormous, and yet it seems to follow certain patterns. What we are seeing today is the result of the dissipation of the enormous energy burst that came with the big bang, some 14 billion years ago. The dissipation occurs in steps, as it is typical of dissipative systems, forming a trophic chain of energy stocks that has some parallels with the kind we know in Earth's ecosphere. In this giant chain of beings, our role seems to be of "star parasites," growing on the light emitted by a star which, from the viewpoint of the star, is waste. Above: an image obtained by the Chandra X-ray telescope. This region shows hundreds of supermassive black holes, each one in a galaxy far beyond our own. (source: Ethan Siegel).

 

Nowadays, we are obsessed with the idea that we need to "produce energy." That is, of course, a wrong way to express the concept. Energy can't be produced: the first principle of thermodynamics tells us that. Energy can only be transformed from a kind of energy to another. And even that is not correct. You can only transform energy going in a specific direction, it is dictated by the second principle of thermodynamics. All you can do, and you can do no more, is to transform high energy potentials into low energy potentials. This is called "potential dissipation." 

An example: what we do when we claim that we "produce energy" is, mostly, to combine atmospheric oxygen with those long-chain carbon and hydrogen molecules that we call "fossil fuels," stored inside Earth's crust. The dissipation process starts with the chemical energy potential stored in crude oil (or gas, or coal), then it goes on in steps, always downhill, until we are left with low-temperature heat, plus water and carbon dioxide. What we covet from this transformation is heat that we then use to run engines and do more things. These intermediate steps we can call "dissipative structures," a term proposed for the first time by Ilya Prigogine.

Can we go back? It is possible, but we can't trick nature and go against the second principle. It is a steep uphill road that of recombining water and carbon dioxide to form again long-chain carbon molecules. We can only achieve that by dissipating an even higher potential, solar light. It is done all the time by plants, it is called "photosynthesis." It is the process that, long ago, created the carbon compounds we are so busy burning nowadays.

This is what makes us "star parasites." We, like the whole Earth's ecosystem, live by dissipating the potential of our star, the sun, and using the energy flow to build dissipative structures: plants, animals, and everything human-made. More correctly, we should say that we are "commensals," a technical term for those parasites that do not compete with their host for resources. From the viewpoint of the star, light is just waste discarded into space. We just intersect a minimal fraction of it and we re-emit it in a slightly lower potential form, infrared light. 

But how about the Sun? Is it a parasite of anything? Not in the same way, but the second principle of thermodynamics holds for the Sun, too. The potential that the Sun is dissipating originated long ago, with the big bang. At that time, an enormous energy potential was accumulated in a very small space. When the big bang came, this energy started being dissipated, a process that has been lasting for 14 billion years and is continuing now. As the universe expands, it cools down. Far from the enormous temperatures of its early life, the universe is now down to just 2.725 degrees Kelvin -- close to the absolute zero. In terms of radiative potential, it is by now dead. Too cold to create new dissipative structures.

But the universe can still create dissipative structures because matter can accumulate into gravity pits. These accumulations concentrate gravitational energy, creating new forms of potential dissipation. Stars are formed by accumulating a vast mass of interstellar dust in a relatively small space. Eventually, a star reaches conditions of temperature and pressure so high that it can start another process of dissipation, turning matter into energy. It is the fusion of hydrogen nuclei into helium ones, a process that, as far as we know, can happen only inside the depth of star cores. It is what makes us star parasites. There are surely other carbon-based lifeforms that do the same around other stars of our galaxy and other galaxies. (image from ESA)

Hydrogen fusion is not the only large-scale energy dissipation process in the universe. There is a sort of "trophic chain" out there, with entities that can be seen as existing at higher trophic levels. Black holes are predators that can devour anything that comes close to them, including stars, and turn it into more internal matter. Neutron stars can be eaten by black holes, but they can eat stars, too. 

Stars themselves have a life of their own. Most of them tend to become brighter and larger as they get older and consume their hydrogen stock. If they are very large, they end their life with the spectacular explosions called "supernovae." The remnant may be a neutron star or a black hole. The debris ejected into space will eventually coalesce to form a new star -- an "offspring" of the old one. So, stars reproduce but, as far as we know, all the information stored in the old star disappears in the cloud of gas that forms as a result. So, there is no transmission of information from a generation of stars to another and no evolution in the Darwinian sense (*). 

The same would seem to be valid for neutron stars, whose destiny is normally to become black holes. Then, black holes are supposed to evaporate over extremely long times by the slow emission of Hawking radiation, again losing all the information that may have been contained inside. (image below from NASA)

That's not the end of the great trophic chain. There is another energy dissipation mechanism: the decay of heavy radioactive nuclides, uranium and thorium. It generates energy that plays a fundamental role in keeping hot, at about 6000 K, the molten core of our planet. It probably does the same for billions of Earth-like planets of our galaxy. This heat is nearly impossible to detect at interstellar distances because it appears as very low temperatures at the surface, probably around a few tens of degrees K. Nevertheless, compared with the background temperature of the universe, Earth-like planets shine.

The decay of heavy nuclides is slow and not very spectacular, but it is fundamental for carbon-based life. A geologically active nucleus generates enough heat to keep the inner layers of Earth hot enough to create the structures we call "hydrothermal vents" at mid-ocean ridges. It is believed that life started at these undersea vents exploiting geothermal energy much before it ventured to the surface and learned how to exploit solar light. Then, life needs a constant supply of carbon dioxide, which is provided by outgassing from the hot mantle. A cold, solid nucleus would not be able to outgas anything and, in such case, the carbon dioxide in the atmosphere would be consumed by reacting with surface silicates and disappear in a few million years at most. A hot inner Earth doesn't just provide CO2 by outgassing. It actively controls its atmospheric concentration by removing carbon by silicate erosion and transporting it to the mantle by the subduction process that takes place at the edges of the crustal plates. And subduction can happen only because of the presence of convective currents in the semi-molten mantle.

So, no radioactive elements, no life. Or, at least, the lifetime of the ecosphere would be much shorter than it is, probably too short to generate complex, multicellular lifeforms.

There is more about radioactive elements: they have a trick that makes them go off in a burst of rapid energy dissipation. It is the neutron-catalyzed reaction that occurs for a sufficiently high concentration of a "fissile" nuclide. In the whole universe, only one fissile nuclide exists in significant amounts: the 235 isotope of uranium: most uranium and the other long-lived radioactive element, thorium, are not fissile, but "fissionable." They can undergo fission, but cannot sustain a chain reaction. 

Even though U(235) is rare, with its half-life of about 700 million years, in very ancient times it was less rare than it is nowadays. So, geological phenomena could accumulate a sufficiently large amount of it to generate a natural chain reaction. It happened at least once in Earth's history, some 2 billion years ago in Oklo, in the area we call today "Gabon," in Africa. Nothing spectacular happened at that time: the chain reaction went on and off several times, generating some heat over a few hundred thousand years. Probably, the place was rich of hot springs at the time, but there were no people who could have enjoyed them. Not even animals existed, they were to appear only one billion and a half years later. So this natural uranium reactor had little or no effect on the ecosystem. 

We don't know if other Oklo-like reactors existed on Earth but, if they existed, they must have been marginal phenomena (even though some people propose the rather improbable theory that the Moon was created in a nuclear explosion). What we know is that, in recent times, the creatures called "humans" managed to process minerals from Earth's crust in such a way to concentrate heavy nuclei at levels where chain fission could be maintained for a certain time. They even managed to "breed" fissile nuclei out of fissionable ones. The flow of energy created in this way is small, a few percent of the energy that humans are generating from fossil fuels, infinitesimal in comparison to the output of a star. But it is there. Could it become much larger in the future and became a significant mechanisms of energy dissipation in the universe? 

It is an especially interesting point because, as far as we know, the only way to run a nuclear chain reaction on a large scale is by having intelligent beings actively control it. We can say that since there is at least one such civilization in the universe (us) and there is no reason to think we are alone. The consequence is that carbon-based sentient beings might use the energy created by fission chain reaction to engage in major feats of planetary engineering and interstellar travel.

 

Of course, we are not seeing anything like that in the universe. This is the essence of the so-called "Fermi Paradox," often understood as meaning that humans are the only technological civilization existing in the universe. In a previous post, I argued that the explanation is the result of two conditions. One is that energy production by controlled nuclear fusion is not possible outside stars, so it is not available to planetary civilizations. The other is that the amounts of radioactive elements available in the solar system are too small to provide sufficient energy to sustain a civilization for a long time. Not even fissionable elements are sufficiently abundant to create more that a transient "flare" of energy dissipation that then would rapidly decline before a civilization could engage in a sustained effort of interstellar exploration.

With the fissile/fissionable resources available, humans, or their extrasolar colleagues, could at most engage in a limited, local interstellar exploration program before running out of energy. More than that, we lack the capability to control what we are doing and it is likely that we'll soon be destroyed by the pollution we ourselves are generating, while at the same time doomed by the depletion of the mineral resources needed to keep civilization going. Or that we'll blow out ourselves using those chain fission reactions we are so proud of. Fortunately, it seems that some 50 years ago we missed the chance we had to embark in a dangerous and ultimately futile nuclear energy program. Now, it is probably too late to gather the resources that would be necessary. Given the current situation, dreams of galactic empires seem to be a little premature.

If we are lucky, we'll just fall back to our normal role of star parasites, after having run out of other forms of potentials to dissipate. That might not be such a bad destiny, considering that the flow of solar energy arriving on our planet is several thousand times larger than the flow of primary energy produced nowadays. But solar energy, although abundant, may not be easy to convert into forms that can power a starship.

So, are carbon-based civilizations destined to remain forever stuck to their home planets? Not necessarily. The universe is not static, it keeps changing albeit at a very slow pace and the availability of fissile materials may be different in the future. We saw that all that is happening in the universe nowadays is the result of the dissipation of the original energy of the big bang. Nuclear fission is no exception. The existence of radioactive nuclei is the result of processes believed to take place mainly in supernova explosions, although it seems that large amounts can also be created in the processes called "kilonovae," the fusion of two neutron stars that generates a black hole. Fissionable nuclei have a half-life of the order of billions of years, so that the universe (14 billion years old) is being progressively enriched with them. 

So, maybe there is a threshold at some moment in the future in which Earth-like planets will be normally endowed with sufficiently large resources of radioactive materials that carbon-based lifeforms might be able to engage in the exploration, and maybe even the colonization, of the galaxy. They might even be able to overcome the limitations of planetary resources by scooping heavy nuclides from the dust around neutron stars or black holes. Maybe we need to wait a few billion years but, from the viewpoint of the universe, a few billions of years are nothing.

This kind of reasoning is, of course, very tentative, but surely fascinating. The universe as a dissipation system appears as a thermodynamic machine. And when you deal with a machine, you can't avoid wondering what is its purpose. Why the universe is the way it is? Why do radioactive elements exist? Why is carbon-based life so dependent on their existence? Why do they exist in the small amounts that we see nowadays? Is the future accumulation of radioactive nuclei planned for some purpose? Are carbon-based civilizations destined to use this energy, someday? Are they supposed to be "filtered" by the danger of the power of nuclear fission? It is a theme that Isaac Asimov already explored in his 1957 short story "The Gentle Vultures." 

Surely, we need to avoid the mistake of the fleas that think that the dog was created for them. But, who knows? The flea God may be more powerful than what we can imagine.

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(*) It has been hypothesized that DNA-like structures could exist inside stars, formed by the combination of "cosmic strings" and "magnetic monopoles." But, for what we can say, these lifeforms cannot move out of their stars and maybe they can't even perceive the existence of the universe outside. Something similar holds for neutron stars, despite the attempt by Robert Forward in his novel "Dragon's Egg" (1980) to imagine living beings composed of neutronium. Black holes, then, tend to destroy information and have an extremely long life. Of course, there may exist things we can't even remotely imagine in the universe but for the time being that seems to be a safe assumption. Incidentally, I went back to read Forward's novel and I found it incredibly boring. Times are changing and the novel is by now an obsolete art form.