The False Hope Behind Nuclear Fusion
For many of those – now a clear majority – who believe climate change is a serious long-term threat, and who therefore believe we must stop emitting carbon dioxide into the atmosphere by burning fossil fuels, the recently announced breakthrough by the Lawrence Livermore National Laboratory’s National Ignition Facility in California that nuclear fusion has at last produced net energy is an extremely hopeful sign.
They need to think again.
Fusion versus fission
Nuclear fusion has, of course, produced net energy before – in a thermonuclear bomb. Much more powerful than a fission bomb of the type that was dropped in 1945 on Hiroshima and Nagasaki, the fusion bomb – a thermonuclear bomb, also called a hydrogen bomb – has thankfully never been used in war. It has been tested, though, and one test explosion destroyed the island of Eniwetok in the Marshall Island chain in 1952.
To understand the relationship between fission and fusion, the best way is to read John McPhee’s short 1974 book, The Curve of Binding Energy, about Theodore Taylor, a Manhattan Project scientist.
Nuclear fission produces enormous quantities of heat when a heavy atom such as uranium-235 breaks apart when hit by a neutron. In addition to the heat, the collision results in two smaller radioactive atoms and additional neutrons that continue the chain reaction by hitting other nearby uranium atoms.
Nuclear fusion, by contrast, doesn’t “fission” atoms (“a splitting or breaking up into parts”); it “fuses” them. Specifically, it fuses two hydrogen atoms into a helium atom, just like the Sun does. Under extreme pressures and temperatures, two hydrogen atoms will fuse to become a helium atom, with heat energy as a byproduct. It is this process that powers the Sun’s heat and energy-bearing rays.
Uncontrolled and controlled fission and fusion
In a fission bomb, the fission chain reaction takes place but, unlike in a nuclear fission power plant, it is uncontrolled. And to explode, it needs a much higher concentration of U-235 than a power plant. In the bomb, unlike the power plant, no effort is made to siphon off the heat created for a useful purpose, or, of course, to protect nearby people and structures from any effects of the reaction.
A fusion bomb, paradoxically, needs a fission bomb to make it work. To create the extreme heat and pressure needed for fusion, a fission bomb is detonated. Except this time, it is controlled only in the sense that it is carefully designed to surround and encase a fusion weapon, applying its heat and pressure evenly to trigger the fusion.
Nuclear fission is controlled in a nuclear power plant by inserting neutron-capturing material between uranium fuel-containing structures within the core of the reactor. The heat generated by the fission process is extracted by a cooling material, usually water, in order to deliver it for a useful purpose – in the case of electric power generation, to boil water to create steam to force the blade of a turbine to spin within a magnetic field. (Using nuclear energy – or for that matter, coal – for this purpose has been likened to “using a chainsaw to cut butter.”)
The temperature in the middle of the Sun is about 15 million degrees Celsius or 27 million degrees Fahrenheit. This is enough to make fusion work because there is also great pressure in the middle of the sun. But to make fusion work on Earth requires a much greater temperature, an incredible hundred million degrees Celsius or 180 million degrees Fahrenheit, because the pressure is much lower on Earth.
The climate change urgency
If it weren’t for climate change, we probably wouldn’t be seriously considering nuclear fusion as an energy source at all. Most likely, we wouldn’t be considering a resurgence of nuclear fission either. Nor would we even be promoting wind and solar power. We would be content with fossil fuels: coal, oil, and gas.
The first heyday of nuclear fission was in the 1960s and early 1970s when it was thought cheap, and of solar and wind power in the 1970s when it was thought we were running out of fossil fuels. Also, burning fossil fuels – gasoline in automobiles, coal in power plants – was causing serious air pollution and associated health problems.
Those concerns of the 1970s were abated by the constant discovery and extraction of additional fossil fuels, particularly gas, and air pollution abatement technologies: scrubbers for coal-fired power plants and catalytic converters for road vehicles.
But more recently there has been a different reason to promote energy technologies like wind, solar, and nuclear that do not emit carbon dioxide: the temperature increases and climate change caused by CO2 emissions. The more CO2 is emitted, over time, the more temperature will increase. Recognition and concern about this problem has accelerated since the 1980s.
Nuclear fission has unjustly acquired a bad name, because of its association with atomic bombs and their radioactive fallout, and unscientific fears of radiation. In fact, nuclear fission has one of the best records for protecting human health of all energy technologies, safer even than wind power.
Nevertheless, the misperceptions about the dangers of nuclear radiation, especially from the waste products of fission, are so widespread and so deeply held by so many and so hard to rebut – and so vehemently championed by a small number of well-funded environmental non-governmental organizations – that those seeking a deus ex machina solution to climate change have embraced nuclear fusion as the ultimate solution. They think that because its byproducts are not radioactive elements but harmless helium, and its input is abundant hydrogen, it is the long-sought-for perfectly safe solution.
Let us examine that assumption with the aid of a thoroughgoing evaluation by a highly knowledgeable scientist.
The Jassby article
Daniel Jassby is a retired research physicist who worked on nuclear fusion experiments for 25 years at the Princeton Plasma Physics Laboratory. He says, “I began to look at the fusion enterprise more dispassionately in my retirement. I concluded that a fusion reactor would be far from perfect, and in some ways close to the opposite.”
His 2017 article in the Bulletin of the Atomic Scientists, “Fusion reactors: Not what they’re cracked up to be,” made it clear that the latter quote was an understatement. His ultimate conclusion is that, “Terrestrial fusion energy is not the ideal energy source extolled by its boosters, but to the contrary: It’s something to be shunned.”
The odd thing is that much of what Jassby said is wrong with fusion reactors is wrong not because their problems are different from those of fission reactors, but because they are similar to them, but worse. Their problems include: larger quantities of radioactive waste than the waste from nuclear fission, albeit of lower radioactivity; equal or greater danger of nuclear weapons proliferation; greater impact on water resources if water-cooled; more corrosion of plant walls and components; and lesser economic viability.
Compression of ordinary hydrogen to create helium in the middle of the Sun is feasible because of the enormous density there as well as the high temperature. But to make it work on Earth requires using the heavier isotopes of hydrogen, deuterium and tritium, which have one and two neutrons in the core of their atoms, respectively. But this means that when deuterium or tritium atoms are fused there will be a lot of extra neutrons flying about.
But unlike what happens in solar fusion – which uses ordinary hydrogen – Earth-bound fusion reactors that burn neutron-rich isotopes have byproducts that are anything but harmless: Energetic neutron streams comprise 80 percent of the fusion energy output of deuterium-tritium reactions and 35 percent of deuterium-deuterium reactions.
Now, an energy source consisting of 80 percent energetic neutron streams may be the perfect neutron source, but it’s truly bizarre that it would ever be hailed as the ideal electrical energy source. In fact, these neutron streams lead directly to four regrettable problems with nuclear energy: radiation damage to structures; radioactive waste; the need for biological shielding; and the potential for the production of weapons-grade plutonium 239—thus adding to the threat of nuclear weapons proliferation, not lessening it, as fusion proponents would have it.
Flying neutrons will damage power plant structures, requiring them to be replaced frequently. The structures that will be replaced will be contaminated with low-level radioactive waste in much greater quantities than the radioactive waste from nuclear fission. Given the public antipathy toward radioactive waste, it will be difficult to find a place to store this or ways to transport it. And replacing those structures will mean high cost.
Flying neutrons also means that uranium oxide can be placed in their path to create plutonium 239, which can be used in atomic bombs. Hence, any country that has a fusion reactor would have a means to develop nuclear weapons. Thus, fusion reactors could pose an even greater danger of nuclear weapons proliferation than fission reactors.
Fusion reactors using a mix of deuterium and tritium will work better than those that use only deuterium, but tritium does not occur in nature, so it will have to be created by fission reactors. Therefore, fusion reactors will not eliminate the need for fission. Furthermore, radioactive tritium could be released in quantities thousands of times that which is occasionally released by fission reactors, engendering protests in the radiation-allergic public.
These are only a few of the problems Jassby raised with nuclear fusion as an energy technology for producing electricity to replace fossil fuels. A nuclear fusion plant would be an intensely radioactive environment, so all workers would have to have biological shielding even when the plant is not operating, and remote handling equipment and robots would be required for all maintenance work and the replacing of parts, causing prolonged downtimes even for minor repairs.
Furthermore, Jassby said, “A reactor fueled with deuterium-tritium or deuterium-only will have an inventory of many kilograms of tritium, providing opportunities for diversion for use in nuclear weapons. Just as for fission reactors, International Atomic Energy Agency safeguards would be needed to prevent plutonium production or tritium diversion.”
Jassby does not believe commercial nuclear fusion is a possibility for 100 years, if ever. Its economic viability would likely be fatally harmed by the above considerations as well as several others he mentioned, such as its “parasitic energy” needs – the need for large amounts of energy to be fed into it even when it is not operating – and its massive requirements for cooling water.
Yes, it’s possible that over the next 50 years economical solutions to these problems could be found. It was believed 50 years ago that artificial intelligence – AI – could never work, for example for voice recognition, yet gradual chipping away at the problem made it work. But nuclear fusion is a steel-and-concrete type of project, not a digital project. Steel-and-concrete projects, as Vaclav Smil makes clear, are much harder and take much longer to get to work.
Why is there so much utopian enthusiasm for nuclear fusion, as if that were the ultimate solution to our climate change problem? It is likely to be very expensive. We already have nuclear fission, which is expensive but works – and has not always been that expensive, and is not expensive everywhere, so it doesn’t necessarily need to be.
Part of the reason for the embrace of nuclear fusion is, I believe, our weirdly distorted view of nuclear fission. There is an implicit belief that nuclear fission is world-destroying deadly, because, as I am often reminded by opponents of nuclear fission, “Nuclear waste remains radioactive for a hundred thousand years!” Without examining the flaws of this argument, let us be reminded that climate change, conceivably the alternative to nuclear energy, will be an increasingly big problem, a much bigger problem for a hundred thousand years also, if we don’t do something about it. And while developments in energy storage may help address its intermittency problems economically, contrary to too much popular belief, “renewables” – wind and solar energy – won’t solve the problem entirely on their own.
There are other promising energy technologies to be researched that hold distant future possibilities for massive success – perhaps not even so far distant. For example, enhanced geothermal, if it could be made to work economically, given the success of fracking technology, could unleash untold amounts of energy a few miles deep in the earth’s mantle.
And if sharply focused research on nuclear fission could be brought to bear specifically to bring down its cost, as concerted research over 50 years did finally succeed in doing for wind and solar, perhaps the objection to nuclear fission that it is uneconomical could be overcome.
There is nothing wrong with continuing research on nuclear fusion – apart, perhaps, from the fact that its application is more to the testing of nuclear weapons than energy. But there is no sense to its displacing nuclear fission in the public imagination by thinking, as some do, “We don’t need fission because we will eventually commercialize fusion.”
This is magical thinking.
Should you invest in any of the plethora of nuclear fusion-pursuing companies that have arisen? Maybe, but don’t expect your return to come from the commercialization of fusion energy; expect it to come from the government. The National Ignition Facility is funded by the US National Nuclear Security Administration’s Stockpile Stewardship Program – not to produce energy but “[b]ecause it is the only facility that can create the conditions that are relevant to understanding the operation of modern nuclear weapons.” In other words, the funding is defense-related. Other countries are also pouring large amounts of money into research on nuclear fusion. A government contractor might be able to draw a good income from governments for fusion research for a long time, even if there are no commercial revenues.
Economist and mathematician Michael Edesess is adjunct associate professor and visiting faculty at the Hong Kong University of Science and Technology, managing partner and special advisor at M1K LLC. In 2007, he authored a book about the investment services industry titled The Big Investment Lie, published by Berrett-Koehler. His new book, The Three Simple Rules of Investing, co-authored with Kwok L. Tsui, Carol Fabbri and George Peacock, was published by Berrett-Koehler in June 2014.