one of the greatest Problems with nuclear energy are not producing electricity, but what is left after. Spent reactor fuel contains highly radioactive materials that can remain dangerous for tens of thousands of years. Managing this legacy is one of the great technological and political challenges of atomic energy.
Now, scientists from the Chinese Academy of Sciences have found a promising solution. Its new experimental reactor, currently under construction in southern China, aims to do something that for decades has been almost a dream of nuclear engineers: generate energy while destroying some of the most problematic radioactive waste.
The system is based on a technology known as an accelerator-driven subcritical reactor, or ADS. It is a hybrid concept that combines a nuclear reactor with a particle accelerator. Unlike traditional reactors, The core of the system cannot maintain a chain reaction on its own. It only works when it receives a constant flow of neutrons generated by an external accelerator. This feature introduces an important advantage: if the accelerator is turned off, the nuclear reaction stops automatically. In theory, this eliminates the risk of the reaction getting out of control.
The key to the Chinese project is how these neutrons are generated. In the system designed by the researchers, a powerful beam of protons from a superconducting linear accelerator is launched against a liquid alloy of lead and bismuth at approximately 80% of the speed of light.
The impact produces a true neutron shower. These particles, when interacting with nuclear fuel, can split heavy atomic nuclei that would not normally be used in a conventional reactor. In particular, the process can transform uranium-238 (a very abundant material but of little use in traditional reactors) into plutonium-239, a much more efficient nuclear fuel. According to those responsible for the project, This mechanism would allow uranium to be used up to a hundred times better than in current plants.
Physicist He Yuan, deputy director of the Chinese academy’s Institute of Modern Physics, has described this approach as a way of turning “waste into treasure.” But that’s not all. In addition to generating energy, these reactors could significantly reduce the danger of nuclear waste. An important part of spent fuel is made up of elements known as long-lived actinides, whose radioactivity can persist for tens or even hundreds of thousands of years. However, the intense neutron fluxes generated in an ADS system can fragment these heavy nuclei and transform them into much less durable isotopes.
If the process works as its designers expect, The radioactive life of some waste could be reduced to less than a thousandth of its current life.The projectknown as the China Accelerator-Driven System Initiative, began development in 2011 and is being built in the city of Huizhou, Guangdong province. When it comes into operation, scheduled for 2027, it will become the world’s first prototype of a megawatt-scale ADS system, an important step towards the possible industrial application of this technology.
For now, no country operates commercial reactors of this type. However, the idea has attracted the interest of scientists around the world for decades, precisely because it promises to solve two of the historic problems of nuclear energy: the limited use of fuel and the accumulation of long-lasting waste.
If the results of the Chinese experiment confirm expectations, accelerator-driven reactors could change the energy equation of the 21st century. Not only would they allow us to obtain much more energy from the same fuel, but they would also They would also help reduce the radioactive legacy that today worries future generations.. And in that scenario, nuclear energy could go from being a limited resource to becoming a source capable of feeding humanity for centuries.