Elon Musk is right: no fusion is needed. The future we won't have

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Elon Musk is right: no fusion is needed. The future we won't have
Elon Musk is right: no fusion is needed. The future we won't have
Anonim

Before mass thermonuclear power engineering 20 years - and always will be 20 years. This simple joke itself became old 20 years ago. Society is upset that thermonuclear still cannot be brought to an industrial level. And only Elon Musk believes that a thermonuclear reactor is not needed at all. A careful analysis shows that he is right. Even if all the technical problems of thermonuclear energy are miraculously resolved, it will have no chance of ousting competitors. How did it happen, and what then will save humanity from the energy crisis?

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First, let us state a fact: there is a serious energy crisis on the planet. There is enough carbon fuel on it, it's true. But even the safest of them all, natural gas, kills 4,000 people for every trillion kilowatt-hours produced. Coal, not to mention biofuels, kills a lot more - after all, when burned, it produces more micrometer particles (PM2, 5). Namely, they, penetrating the lungs into the bloodstream, kill people, causing thrombosis, heart attacks and strokes, which we all mistake for the usual "diseases caused by stress." In the United States, tens of thousands of people die every year from thermal energy, and in the world we are talking at least hundreds of thousands of deaths annually. This problem has long and seriously worried scientists, Soviet academicians, back in the 1980s, considered the rejection of thermal energy to be an inevitable future - precisely because of these environmental considerations.

This situation is little known to the modern public, and you will not hear about it from politicians. However, both the public and politicians are aware of other considerations that call for the abandonment of carbon energy - "warming". According to them, global warming is a catastrophe, and in order to avoid it, carbon fuels must be abandoned.

"Fusion energy is not needed."

Elon Musk

We have written more than once that in reality, global warming reduces mortality. For example, in the latest research on this topic - by 15 thousand people a year in the last 20 years alone. We also wrote that anthropogenic carbon emissions led to a record flourishing of terrestrial vegetation and a significant increase in harvests. But all this does not mean at all that there is no need to fight against carbon fuels. The theses of the Soviet academicians are not outdated even today: carbon fuel kills a huge number of people every year, including in Russia.

So what does modern science and technology have to offer to finally end this invisible war that kills hundreds of thousands every year? When will thermonuclear power engineering turn off the last TPP? Alas, never.

The advantages of fusion are undeniable …

Fusion energy since the 1960s - half a century! - promises us unprecedented prospects. A kilogram of plutonium when decaying gives 23.2 million kilowatt-hours (in terms of heat), and a kilogram of deuterium and tritium in fusion reactors - 93.7 million kilowatt-hours per kilogram. The difference is four times, which is a lot. In addition, there is more water on the planet than nuclear fuel, and 1/6500 of all water is deuterium, thermonuclear fuel.

The second advantage of a thermonuclear reactor: when the nuclei of its fuel atoms merge, helium and a neutron are obtained. One way or another, a neutron will not fly far from the reactor, and helium is harmless.A certain amount of radioactive tritium in the process flows out of the nuclear fusion zone, but does not leave the reactor, and the radioactivity from it, to be honest, is negligible. The half-life of tritium is 12.3 years, much less than that of typical hazardous isotopes remaining from the decay of uranium and plutonium atoms (these are, for example, unstable isotopes of cesium). If nothing is done with the spent fuel from a nuclear power plant, it will remain unsafe for thousands of years. The spent fuel of a fusion reactor will be safe in 150 years.

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The third advantage of a thermonuclear reactor: unlike a nuclear reactor, a self-sustaining reaction is impossible in it. Without enormous efforts to maintain high pressure and temperature, the reaction will stop immediately. The surrounding substance of the reactor cannot fuel the reaction in any way: there the nuclei of atoms are heavier than deuterium and tritium. Their merger simply will not give an energy release that could melt the core (as in Fukushima) or overheat the coolant (as in Chernobyl). A clear plus for security. At least it seems so at first glance.

Alas, all these advantages that we have been told about for decades, to put it mildly, do not quite accurately describe the situation. No more than stories about the upcoming transition to "continuous solar and wind energy".

…Or not

Let's start with increased fuel efficiency. Undoubtedly, deuterium and tritium provide four times more energy per kilogram of fuel, but there is a nuance. It lies in the fact that there is no shortage of fuel in nuclear power - not even close. Let us remind you that a reactor using plutonium is already operating in Russia. This is a breeder reactor: in it, plutonium can be produced from ordinary uranium-238, receiving more fissile fuel (plutonium) at the output than at the input.

Russia alone has more than 700 thousand tons of uranium-238 already mined. Even with a modest efficiency of 34%, more than 5.5 quadrillion kilowatt-hours can be obtained from this. This is the consumption of the entire planet for more than 200 years. It should be understood that there is also quite a lot of uranium-238 already mined in other countries. That is, using fast reactors and not extracting any uranium ore at all, mankind will be able to cover its energy needs for many centuries. If it also mines ore, then in the next tens of thousands of years, the problem of "lack of fuel" should be immediately forgotten. And we did not even touch on the fact that there is much more uranium in seawater than in uranium ores on land.

The second advantage of fusion - the short life of its radioactive waste hazard - has a similar degree of relevance. The point is that the already existing fast reactors of the BN-800 type make it possible to use 95% of all spent fuel. A molten salt reactor planned for construction in Siberia is capable of drawing another 4% into the power cycle. Only one percent remains - but it consists of isotopes, which in 500 years will have radioactivity at the level of natural uranium ore.

For thermonuclear fusion, this period is 150 years, which seems to be an advantage. But the fact is that to provide energy to the entire planet for 500 years ahead, about 10 million tons of nuclear fuel are needed. One percent of this number is one hundred thousand tons. Due to the high density of nuclear fuel, it is only a few thousand cubic meters. If you collect all of them in one place, you get a cube with a side of less than 20 meters. This is an extremely small volume that can be easily stored directly on open sites of operating nuclear power plants, as is actually done with radioactive waste today, in durable containers.

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But the waste of thermonuclear energy, although smaller in mass, is radically less dense. Therefore, despite the storage period of 150 years, they will take about the same amount of space in open areas as waste from nuclear reactors.

Okay, but what about security? It seems that here the advantage of thermonuclear fusion is undeniable: it cannot have an uncontrolled reactor runaway?

And again the statement is essentially true … but again there is a nuance.It is that in modern nuclear reactors there can be no serious uncontrolled acceleration either - simply by virtue of the laws of physics. If the acceleration of the nuclear fission reaction begins in an existing nuclear power plant, both the fuel itself and the coolant next to it will heat up. In an ordinary serial reactor, heat is removed by water - and when overheated, it will boil, drastically losing its density. But the same water slows down thermal neutrons, and if it becomes less dense, the slowdown falls. Fast neutrons are captured by uranium-235 much worse than slow ones, and the fission reaction will automatically slow down sharply.

In a fast reactor of the BN-800 type, the situation is different. There is no moderator there; a small part of the neutrons is captured by the sodium coolant. But even when heated, it sharply loses its density and thereby changes the neutron properties inside the reactor. He again slows down. Himself, simply by virtue of the laws of physics.

That is, yes, a thermonuclear reactor cannot accelerate uncontrollably … but this does not give it any advantages over modern nuclear power plants, because they cannot do this either.

But what about Chernobyl - why was there an uncontrolled dispersal and death of people? The thing is that there was a completely different type of reactor - an unmodernized RBMK. Strictly speaking, by itself, he also could not accelerate uncontrollably. But during the design, a miscalculation was made, due to which the deceleration of neutrons in the core, when the emergency braking rods were inserted, increased, and did not fall. This flaw was known to the designers, and they notified the NPP with such reactors about it - but they did it in a language incomprehensible to ordinary people, which is why Chernobyl happened.

"Modern nuclear reactors are safe - contrary to what people think."

Elon Musk

But with today's reactors this situation is impossible for purely physical reasons: they were originally designed so that pressing the "nuclear brake" pedal does not lead to their acceleration, as was the case with the RBMK.

Let's summarize. All three theoretical advantages of fusion reactors - excess fuel, a solution to the problem of radioactive waste and safety - have already been solved for nuclear reactors. Moreover, as we will show below, this is not all.

Why will nuclear reactors be better than thermonuclear reactors in half a century?

The key problem with fusion is that it will not be able to compete economically with nuclear power plants - most likely, never.

The point is that for the fusion of atomic nuclei, they need to overcome the Coulomb barrier. In the center of the Sun it is easy to do this: there are tens of millions of degrees around and enormous pressure. There is no such pressure in a thermonuclear reactor and it is necessary to compensate for this by additional heating - at least up to one hundred million degrees. Hotter than at the center of the Sun and thousands of times hotter than on its surface.

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The fusion reactor heats the plasma with deuterium and tritium to such temperatures, keeping it in the strongest magnetic field. It is the strongest because if such a plasma is not kept in the center of the vacuum chamber, then it will damage any conceivable material - it will simply burn it out.

Well, this type of magnetic trap requires large, super-powerful magnets made from superconducting materials - and cooled by liquid helium. Setting up such a hold is fantastically complex and very time consuming. Including due to it, the experimental thermonuclear reactor ITER costs 25 billion euros. This is the price of six gigawatt reactors of Rosatom - with an annual output of fifty billion kilowatt-hours. Let us remind you that this is equal to one-twentieth of the energy consumption of a country like Russia.

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But the ITER capacity is not at all half a dozen gigawatts, but only 500 "thermal" megawatts. Moreover, the reactor is experimental - it cannot produce it constantly, only during short pulses. And its energy consumption in heating mode can exceed 700 megawatts, which is more than the possible energy return.

Let's imagine for a second that all the problems of thermonuclear reactors have been solved, they keep the plasma constantly and do not spend any energy at all on heating it.Maybe thermonuclear fusion will become competitive at least then?

Unfortunately no. With existing and future types of reactors, this is simply impossible. Let's take the same ITER: the reactor there is 30 meters high and 30 meters in diameter, the power, we recall, is only 500 thermal megawatts per pulse. A conventional nuclear reactor BN-800 has a core height of less than a meter and a diameter of about 2.5 meters. Moreover, its constant (and not pulsed) thermal power is more than 2000 megawatts. By the way, future thermonuclear reactors will be even larger than ITER. It is clear that the building around ITER (and its successors) needs to be radically larger and more expensive than around the BN-800 (and this is the case in practice).

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In addition, the cost of a fusion reactor should include a large vacuum chamber (which a nuclear reactor does not need). And a huge set of superconducting magnets with cooled liquid helium. It is easy to understand that when they are taken into account, it is quite difficult to compare thermonuclear and nuclear power plants economically.

Let us make a separate reservation: all this remains true for any changes in prices for deuterium, tritium, uranium or plutonium. The fact is that even at nuclear power plants, the share of the fuel price in the total kilowatt-hour is only 5%. Conceivable changes in this price, therefore, have almost no effect on the cost of electricity. Capital investments in construction are the most influential - and they are much higher for thermonuclear reactors. And they will remain higher for the foreseeable future.

The reason is everything in the same physics. To start a nuclear reactor, simply bring the rods with plutonium-239 or uranium-235 close to each other. The neutrons that their atoms emit spontaneously will themselves start a chain reaction of nuclear fission. To launch a thermonuclear one, you need a multi-meter vacuum chamber with a hundred million degrees in its center. There are no ways of development that would allow such a structure to have the same price as a small (2x1 meter) container with sodium - without any vacuum, and with temperatures deliberately below one thousand degrees.

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The bulk of the cost of both nuclear power plants and thermonuclear power plants is capital investment. And for the latter, they will always be much higher than for nuclear power plants. And this obviously overrides any savings due to the lower mass of fuel consumed.

It should be clarified separately: despite all that has been said, ITER is a wonderful scientific project, something like the Large Hadron Collider. Yes, it is expensive, but it allows you to learn more about the control of high-temperature plasma, which sooner or later may be useful in completely different areas. You just shouldn't expect future energy abundance from it: there is no such sin as low prices behind thermonuclear reactors.

So what happens - there is no way out of the energy impasse?

The same Elon Musk believes that there is no need for a thermonuclear reactor also because one such is already burning in the sky. It is enough to collect his energy, the entrepreneur believes, there is no point in trying to build a new one. However, unfortunately, solar energy cannot become the main source of global generation either. And this, if anything, is one of the reasons why the same Musk is advocating the construction of nuclear reactors.

We have more than once described in detail why wind and solar energy will not be able to close carbon energy. For developed countries, this is technically impossible, even if you equip them with a huge number of energy storage devices. After all, both the United States and the EU, and almost all developed countries of the world are located in those parts of the world where the winter output of solar power plants is several times lower than the summer one. It is impossible to store energy for six months in advance: the required volume of batteries for the United States will cost as much as their annual GDP. Wind turbines will not be able to cope with the same task due to long frosty anticyclones, when their output can drop to zero altogether.

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Separately, we considered the issue of why hydrogen energy is not able to solve this issue by the accumulation of hydrogen generated in summer (and during the period of strong wind) and the consumption of this hydrogen in winter.In short: such "green hydrogen" is so expensive that an attempt to use it on a mass scale torpedoes even the most powerful economy.

Above, we have discussed why thermonuclear energy can never become more promising than nuclear. It turns out that there is no way out at all?

In fact, the situation is a little more complicated. The solution, in theory, has been around for forty years, but in practice it can be guaranteed that no one will use it.

Let's take a sober look at the situation: today's world is not only based on carbon energy, but is doing everything to stay based on it in the future. Every politician and every environmentalist who stands for the complete replacement of thermal power plants with wind turbines and solar panels, in fact, stands for eternal dependence on thermal power plants. The thing is that we outlined above: windmills and solar power plants have an unstable output, which is least of all on windless winter frosty days.

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The more you commission wind power plants and solar power plants, the more you will depend on electricity from thermal power plants in winter. For example, mainly nuclear France in winter depends little on thermal power plants: its power plants operate 24 hours a day, regardless of the weather. Denmark depends on thermal power plants (including thermal power plants of its neighbors) much more in winter: its wind turbines are in the frosty anticyclone.

This approach has a carbon-free alternative, clearly formulated during the Soviet era: the atom. Nuclear power plants produce energy at a price slightly higher than thermal even in Russia, where gas prices are much lower than in Asia and slightly below the average for Europe. Back in the USSR, the construction of nuclear power plants began, providing not with electricity, but with heat - despite the fact that it is heat that accounts for the bulk of the energy expenditures of our civilization. Moreover, it is known from historical experience (see the graph below) that the commissioning speed of nuclear power plants can be enormous, several times higher than the speed of commissioning solar power plants and wind turbines.

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It is easy to see in the graph above: France and Sweden, without the slightest overstrain of their economies, commissioned so many nuclear power plants in the 1980s that they added 440-630 kilowatt-hours of "atomic" electricity per capita every year. Modern developed countries consume about 9 thousand kilowatt-hours per capita (in Russia, of course, less - only 7 thousand per capita). This means that it takes 15-20 years to replace the carbon energy of a modern developed country with an atom (Sweden could do 15, France could do 20). By historical standards, this is an almost instant substitution.

It is precisely clear that solar and wind generation cannot provide such rates. And we are now not only about Denmark in the chart above - the same is the case all over the world. In 2020, 113 gigawatts of wind power plants and 178 gigawatts of solar power plants were commissioned. Their total output per year is approximately 480 billion kilowatt-hours. This means that SPP and WPP over the past year added 60 kilowatt-hours of generation per capita on our planet.

If it seems to you that 60 kilowatt-hours per capita per year is ten times less than in Sweden in the 80s, or seven times less than in France in the 80s, then do not rush to conclusions. In fact, everything is even worse than you think.

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The fact is that the nuclear power plant has been operating at the same capacity for half a century. In fact, their capacity is often increased after start-up due to thermotechnical optimization, but we will even omit this point. So, half a century at the same power - but the wind turbine needs to be changed after 25 years of service. Due to degradation, the solar battery loses 0.5% of its capacity per year - that is, in half a century its production will drop by a quarter. Then they will change it, because there will be no point in tolerating a decrease in production.

If, instead of these solar and wind power plants, nuclear power plants with an output of 480 billion kilowatt-hours (60 kilowatt-hours per capita of the planet) were introduced in 2020, then these nuclear power plants would produce 480x50 = 24 trillion kilowatt-hours in their lifetime. The SES and WPPs introduced in reality will produce - taking into account their shorter service life - less than 15 trillion kilowatt-hours in a lifetime.

This means that the introduction of carbon-free generation in France in the 1980s was not seven times higher than the introduction of carbon-free generation in the world today. No, he was twelve times taller. The current carbon-free transition is twelve times slower than it was in the 1980s.

If we build SPP and WPP at the pace of 2020, then we will cover all the world's electricity needs in (in theory) 50 years. This figure is obtained if we divide the consumption of electricity in the world (24 trillion kilowatt-hours per year) by the solar-wind generation introduced last year (480 billion kilowatt-hours).

In practice, we will never do this at all. Because in 25 years, the wind turbines introduced today will have to be replaced. And the generation of solar panels introduced today will decrease by 1/8 in 25 years. At today's rate of decarbonization, we will be like Alice Through the Looking Glass - running as hard as we can all the time, just to stay put.

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Why are modern Western ecologists and politicians silent about these facts? Why don't they inform their supporters that the modern carbon-free transition to SPP and WPP is a dozen times slower than the carbon-free transition in France in the 1980s? Why is it not informed that at the current pace of the "transition" it will never end at all - because wind turbines and solar panels will have to be replaced before carbon generation can be replaced?

The answer to this question is very simple: they themselves have not the slightest idea about it. Situations of this kind happen all the time. One scientist faced with this described it this way: “People often think that political decisions are based on some scientific discovery or expert knowledge. But in reality, those who make political decisions often make them only because they seem “pleasant to the ear”. And then scientists with great difficulty try to understand how this could be realized."

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In practice, Western politicians and environmentalists have chosen to switch to solar and wind energy because it is "pleasant to hear." They literally have very apt names - they refer to natural phenomena like the sun and wind. Atom - the name is unfortunate, it refers to the atomic bomb. Therefore, as we have already written, the anti-nuclear movement blocked the development of nuclear power plants in the United States even before Chernobyl (and even before Three Mile Island).

Therefore, it does not matter at all that Chernobyl killed fewer people in decades than thermal power plants in the United States kill every month. It doesn't matter that no other nuclear incident at a nuclear power plant has killed a single person. Despite all this, the chances of nuclear power plants for replacing carbon energy are close to zero: they are “not pleasant to the ear”, neither for politicians, nor for environmentalists.

From this it is easy to predict the future of the world energy and ours. Western politicians and environmentalists will triumphantly tell us about the successes of green generation for more than a decade. All this time, the bulk of the energy on the planet will be obtained in the same way as today: burning carbon fuels. Each next generation of politicians and environmentalists will say that their predecessors were not decisive enough - and promise to "deepen, expand, and rebuild." Each of these generations will not be able to do this, because they have never tried to calculate for themselves why their predecessors in fact did not manage to achieve the "green transition".

And we will continue to inhale the products of combustion of fossil fuels - and die from this in hundreds of thousands a year.

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