written 29 December, 2024
published 5 January, 2025
Last week I described how some of the heavier elements will fission, releasing energy as they get smaller. Modern physics also shows the lighter 26 elements release energy as they get larger through fusion, with the nucleus more tightly bound. The most well know example of this is the fusion of two hydrogen atoms into one helium atom.
Because protons are all positively charged, the electromagnetic force repels them. When that repulsion is overcome, and protons are brought close enough together, the "strong" nuclear force takes over, holding the nucleus together. The core of the sun has pressure 100 billion times our atmospheric pressure, with a temperature of 15 million degrees Centigrade. This is sufficient to initiate hydrogen fusion, and the released energy is what allows life on Earth.
Combustion of any kind (carbohydrates in the body, plant material, or fossil fuels) involves oxidation of hydrogen, which has historically powered life and human civilization. But oxidation of hydrogen involves the electromechanical forces in chemistry. Fusion of hydrogen, involving the strong nuclear force, is 2 million times more powerful, making it an attractive energy source.
The problem with accessing this level of energy is the extreme pressure/temperature needed to make it happen. Once the first fission device was developed in 1945, it was realized this power could be used to initiate fusion by locating a hydrogen core within a nuclear fission bomb. The first hydrogen fusion device was detonated in 1952, rated at 10 megatons of TNT. Russia detonated their first hydrogen bomb a year later, and detonated the largest man-made bomb in 1961, rated at 50 megatons of TNT, 3,000 times larger than the fission bomb which destroyed Hiroshima.
As with the power from fission, efforts quickly turned to trying to make peaceful use of fusion. This is a much more difficult engineering project than a bomb, as controlled fusion needs be sustainable and not destructive. The fundamental problem is still how to generate sufficient pressure/temperature to initiate fusion. Designs using radio waves, magnetic fields, and lasers have been proposed and constructed, trying to generate the necessary conditions and keep them contained.
Over the decades, research has become more globally cooperative, driven by the complexity and massive expense of such a project, with almost 100 fusion experiments now in play globally, and more planned. Billions of dollars are invested annually in the US alone. Successes have been measured in terms of temperatures and energy levels achieved, and duration of actual fusion. Designs have improved, now including superconducting magnets and as many as 200 laser beams.
However, the longest duration of sufficient temperatures yet achieved was 18 minutes, and the longest actual fusion was just seconds. Any power produced is a fraction of the power required to generate the fusion environment. Therefore, commercial fusion power is still described as "decades away".
In 1989, there was a flurry of news about "cold fusion". Two chemists, Fleischmann and Pons, reported excess heat and nuclear byproducts using electrolysis on the surface of an electrode, and the hope was a new form of cheap and abundant energy. However, multiple efforts to reproduce the results failed, so this report was considered an error and the subject declared dead. No peer reviewed literature now mentions cold fusion, and many consider it impossible.
However, some researchers continued, mostly working outside the US, despite limited funding and rejection by the mainstream scientific community. Over time, these investigations have earned enough reputation to become known as Low Energy Nuclear Reaction research. Rather than trying to push hydrogen together, one theory is cold fusion pulls them together, within the cracks of suitable substrate. Perhaps the energy released destroyed the substrate structure, making the first results impossible to reproduce, and research now centers on creating more durable substates.
Science has a history of blind spots, where orthodoxy refuses to recognize changes when they appear. Cold fusion may be one of these and will one day become mainstream. However, that isn't going to happen soon, if ever.
Fusion is still a technologist's dream, and fission is expensive, economically risky, producing eternally lethal waste, consuming finite fuel. No form of nuclear power is going to rescue our troubled energy future. Even the oil industry acknowledges the US fracking boom is over, depleted. Without even addressing the climate crisis, a sustainable technological civilization will require fundamental changes in our energy production, if it is to exist much longer.
