Humanity’s insatiable demand for energy is increasing the incentive for research into the production and application of what is known as “clean nuclear power”: fusion.
For some years now, a research team within the US aerospace company Lockheed Martin has been working on the creation of a compact fusion reactor, CFR for short. This device would be conceptually safer, cleaner and more powerful than the much larger current nuclear reactors which rely on fission rather than fusion.
As we all know, the process of nuclear fusion, where atoms are made to combine in more stable forms and in the process release excess energy, is much safer than nuclear fission, the process of splitting atoms to release energy… but unfortunately it is much more difficult to achieve.
The head of the Lockheed research team, the aeronautic engineer Thomas McGuire, started out by gathering and studying at great length all the research into this field carried out in recent decades, selecting the promising areas and tackling the problem areas and working to resolve them.
The team’s current experiments are focused on a containment vessel whose dimensions are about the size of a jet engine on a private plane. Connected to injectors, sensors, a turbo-pump for generating an internal vacuum and a complex system of batteries, at first sight the stainless steel container involved might seem an unlikely first step towards solving a problem which has defeated generations of nuclear physicists: finding an effective way to control the fusion reaction. But in fact, it has a lot going for it…
Fusion fuel is made up of the hydrogen isotopes deuterium and tritium, and starts as a gas injected into an evacuated containment vessel. Energy is added, usually by radio-frequency heating, so that the gas breaks into ions and electrons, forming a superhot plasma.
Up until now, most attempted fusion experiments have involved a plasma control device called a tokamak, developed by physicists in the Soviet Union in the 1950s. The problem here is that reactors using this system need roughly the same amount of energy input (to maintain the self-sustaining fusion reaction) as the energy output generated.
The CFR will get around this problem by tackling plasma confinement in a radically different way.
The crucial difference in this new approach is that for a same size reactor, the CFR will generate more power than a tokamak by a factor of 10. This in turn means that for the same power generating output, the CFR can be 10 times smaller. And this change in scale is a game-changer in terms of viability, productivity and cost.
The first prototypes of this kind of reactor will be designed to generate roughly 100 MW and to fit into transportable units measuring 23 ft X 43 ft (c. 7 x 13 meters). The 100-MW unit would provide sufficient power for up to 80,000 homes in a power-hungry U.S. city and would also be “enough to run a ship,” McGuire notes.
Lockheed estimates that less than 25 kg (55 lb.) of fuel would be enough to run an entire year of operation. A vital factor is that the fuel itself is plentiful: deuterium is produced from sea water and is therefore considered as being unlimited, while tritium is “bred” from lithium.
The first-generation reactors will have some radioactive parts at the ends of their lives, such as certain steel elements in the containment shell, but McGuire says that the normal contamination situation will be much improved compared to current fission systems, and that a key operational benefit is the elimination of any risk of meltdown, with all the catastrophic consequences which that can cause.
The Lockheed team acknowledges that the project is still in its early stages, and that many important problematic issues remain to be overcome before a viable prototype can be built.
However, forecasts are much more encouraging than even a few years ago: McGuire envisions creating a full prototype for testing roughly five years from now, with full production activity launched in another five years.
These declarations have led some people to hint at the presence of an element of public relations motives on the part of Lockheed’s R&D division, given the intense competitive spirit in this sector. But if competition is honest and contributes to boosting the incentive to create new ways to produce cheaper, safer and cleaner energy, it will be doing the planet and all its inhabitants a huge favor!