Public and private investment is currently flowing into nuclear fusion, with the hope of finally making it a viable energy source. Despite decades of unfulfilled promises, many players are now betting on an imminent breakthrough, driven by recent technological advances and renewed strategic interest.
However, the challenges remain considerable, recalls Gizmodo. Producing and maintaining a stable fusion reaction, capable of operating continuously, involves controlling extreme conditions comparable to those of the Sun. In addition to these technical obstacles, there is now a new concern raised by American researchers: the risks of nuclear proliferation linked to these technologies.
Physicists from Virginia Tech and the Princeton Plasma Physics Laboratory have studied fusion reactors using deuterium and tritium, currently among the most promising approaches. These systems generate a large flux of neutrons when fusing hydrogen isotopes into helium, an essential characteristic for producing energy.
But this neutron flow could also be diverted, and not necessarily out of pure scientific curiosity. According to the researchers, a high-powered fusion reactor could, in theory, be used to clandestinely produce fissile materials such as plutonium-239 or uranium-233. Such a device could generate several dozen kilograms of these materials each week, enough to fuel a nuclear weapons program.
Relatively easy monitoring
Faced with this risk, scientists are proposing a solution based on the detection of antineutrinos. These particles, extremely difficult to detect, are emitted during nuclear reactions involving uranium in particular. Their monitoring is already used in certain nuclear research and surveillance contexts.
The idea is to use antineutrino detectors to monitor the operation of fusion reactors. By analyzing the flow and energy of these particles, it would be possible to spot suspicious activities, such as the hidden production of plutonium from uranium introduced into the reactor.
Simulations show that a relatively compact detector, weighing around one tonne, placed around twenty meters from the reactor, could be sufficient to detect these illicit activities. One of the major advantages of this method is that antineutrinos cannot be blocked or falsified, making it a particularly reliable monitoring tool.
This work remains theoretical for the moment: commercial fusion reactors are not yet operational on a large scale, and the diversion scenarios studied represent only part of the possible risks. Other configurations, particularly involving thorium, could further complicate detection.
The race for fusion must not overshadow security issues and the question of non-proliferation. While fusion promises “clean” and abundant energy, it could also introduce new geopolitical challenges. Anticipating these potential deviations now appears essential to supervise the development of this technology.
