Getting a commercial reactor is a matter of generations, not of years. This is how César Huete Ruiz de la Lira, a researcher at the Carlos III University, summarizes the industrial prospects for nuclear fusion. The scientist recalls that the current milestone had initially been announced for 2003, then it was postponed to 2012 and, finally, it has been achieved 10 years later. “However, it is worth a try. It is something that can radically change the energy landscape & rdquor ;, he affirms.
Reaction fuels are not rare resources: deuterium is extracted from seawater and tritium from lithium, but small amounts of both would be needed, representing a virtually infinite resource.
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The time frame given by Kim Budil, director of the Lawrence Livermore Federal National Laboratory, is decades. The European fusion roadmap foresees the first prototypes of grid-connected reactors by the middle of this century.
Over the next few years, what challenges technologies will be the most important when it comes to developing this type of energy?
Challenge 1: electricity costs
The most obvious obstacle in the US system is the enormous amount of electricity used to charge the experiment’s lasers: 300 megajoules, so that they discharge only 2.01 megajoules on hydrogen. That’s almost 100 times more than the 3.15 megajoules generated by the merger.
LLNL’s lasers are 1980s technology, according to Tammy Ma, a researcher at the center. Newer lasers, especially diode lasers, could achieve much higher efficiencies. However, there will always be a loss in loading them. For this reason, the fusion should generate tens or hundreds of times more energy than that of the lasers, to compensate for this electrical cost.
Challenge 2: the price of the capsules
The hydrogen capsules they are the secret of the experiment. Huete estimates that each of them costs about $10,000. Its manufacture has to be perfect, so that its content does not escape during compression. For industrial production, a pellet with many capsules would be needed, which would require radically lowering its cost.
Challenge three: the walls of the reactor
During nuclear fusion, a large number of neutrons are released that bombard the walls of the reactor. In addition, hydrogen reaches temperatures higher than the interior of stars. “If the reaction occurred for a longer period, the container would melt,” observes José Aguilar Medina, coordinator of IFMIF-DONES, an international center located in Granada that aims to address this problem.
continuous operation
In the LLNL experiment, fusion was induced in a hydrogen capsule for a few billionths of a second. In an industrial reactor, reactions of this type should be generated continuously, with rapid recharging of the lasers and a continuous supply of new capsules. That requires high-powered pulsed lasers, full-speed capsule manufacturing, or synchronization systems that currently don’t exist.