Shading the Scope of a Nuclear Fusion Achievement

Caution before the news on the achievements in nuclear fusion

Article written by Enrique Nácher and José Luis Taín, CSIC researchers at the Institute of Corpuscular Physics

On December 13, 2022, the United States Department of Energy announced at a press conference that the scientific and engineering team at the Nuclear Ignition Facility (NIF) at Livermore National Laboratory had successfully ignited a capsule containing deuterium and tritium obtaining more fusion energy than the energy in the form of laser light that had been transferred to the system. The fact is presented as an undeniable milestone on the road to obtain “usable” energy through fusion, but it is true that there is still a long way to go. Here are some thoughts on it.

First of all, as has been seen, the news has caused a great stir in the media, but it should be noted that no scientific article has yet been published, one of the so-called “peer-reviewed”, in which the experiment is explained, analysis and results. Thus, it is still difficult for the scientific community to assess the result achieved.

To continue, even without knowing the details, we can be critical of the information that comes to us. The progress achieved by the Livermore team has been to measure more energy output than input to the ignition chamber. With this they have announced that the gain factor Q is greater than 1 for the first time. And this is where our critical spirit makes us look for anomalies in the language, the expression, or the definition of the different terms. The concept of gain is essential in fusion technology because, unlike fission technology, the one used by conventional reactors, it is necessary to spend a lot of energy to produce it. Therefore, producing energy through economically viable fusion requires that much more energy be produced than consumed.

It so happens that the definition used by the Livermore scientists differs from that used in the field of magnetic confinement fusion (for example, the ITER project) and does not take into account, for example, that in order to have the lasers working for this shot, consumed approximately 100 times more energy than was produced in fusion, so it could be said that the gain of the system as a whole as an energy “generator” has been rather 0.01, well below 1 .

The fascinating but not without controversy experiment was performed at the Lawrence Livermore National Laboratory’s Nuclear Ignition Facility (NIF). (Photo: Lawrence Livermore National Laboratory)

The true scientific and technological advance is that they have managed to double the energy produced with respect to that announced in a similar news item last year around this time. And in fact, it brings us a little closer to the objective, which still seems distant to us, of having fusion reactors for the industrial production of energy. Not for this reason the result is no longer relevant, but perhaps its implications have been magnified in the media.

In summary, we must be very cautious and critical of the information that is reaching us today in general, and in particular with this flurry of news about the Livermore results and their relevance to the path towards industrial energy production through the nuclear fusion, at least in the medium term. (Source: Enrique Nácher and José Luis Taín, Institute of Corpuscular Physics, CSIC)