Sep 25, 2023
Sep 25, 2023
As the ‘rosy-fingered dawn’ appeared on the eastern horizon, our sages of yore, staring at its rich luster in awe and reverence, offered their prayers — “... Sarva mangala maangalye sarva paapa pranaasanam/Chintaasooka prasamanam aayuvardhana-muttamam—The Sun Lord is auspicious and bestows auspiciousness / He subdues grief and worries, and nourishes life”.
Scientists have however looked at Sun with an enquiring eye and came up with an explanation that the light radiated by it is powered by protons of hydrogen atoms careening into one another in the Sun’s heavy, sweltering core, fusing, and releasing energy in the form of sunlight and heat. And driven by this understanding, scientists have pursued one of the toughest challenges ever conceived for more than 60 years: to mimic this stellar phenomenon in laboratories to harness nuclear fusion to produce clean, cheap, and limitless energy here on earth.
But simulating the necessary conditions for fusion to happen in the laboratories turned out to be daunting. For, in the absence of Sun’s massive gravitational force that naturally induces fusion, it became necessary to create temperatures exceeding 100 million degrees Celsius coupled with intense pressure to make the fuel, deuterium and tritium, fuse. Secondly, the creation of sufficient confinement to hold the plasma and maintain the fusion reaction long enough for a net power gain proved to be even more difficult. However, seven decades of research has paved the way for their creation, though improvement is desired in the confinement properties and stability of the plasma.
Against this backdrop, scientists working on fusion energy at the National Ignition Facility (NIF) in the Lawrence Livermore National Laboratory, California, announced on December 5 that they have finally been able to reproduce the power of the sun in a laboratory: it produced the first fusion reaction that yielded more energy – about 50% more than what it took to start it. This announcement of NIF has been described by Prof Mathew Zepf of Friedrich Schiller University as “a major achievement on the road to fusion energy.”
These results of the ‘inertially confined fusion’ method, in which charged lasers are used to zap a pellet of frozen deuterium and tritium, the two heavier isotopes of hydrogen, in a tiny cylinder with a lot of power to trigger an explosion that produces a fusion reaction, are however embedded with many caveats. Though the energy lasers produced (2.1 megajoules) was smaller than the energy that the fusion reaction produced (2.5 megajoules), the energy needed to charge the lasers was more than a hundred times that (about 400 megajoules), and thus the output ratio of energy is not all that encouraging.
In view of this, many experts, while acknowledging the historical significance of the experiment, cautioned that it may not mean much for a green energy transition. Betti, a physicist at the University of Rochester, said that for the success of a reactor of NIF’s style, it would need to generate 50 to 100 times more energy than its lasers emit to put power into the grid.
Nevertheless, the success of NIF experiment proved that fusion energy is plausible. It is now a question of overcoming the significant technological hurdles in the commercial production of fusion energy, for it has to compete against zero-carbon alternatives such as fission-based nuclear reactors, which can generate a steady supply of power, and renewables like wind and solar energy that are cheaper but, of course, intermittent.
An aside of the success of the NIF’s experiment is: it will aid the scientists to generate necessary data by performing these nuclear reactions in the lab instead of resorting to the highly destructive underground nuclear bomb detonations, to evaluate the nuclear stockpile.
There is, of course, another method, which is more widespread among companies that are working towards commercializing fusion energy. It involves trapping hydrogen plasma within a magnetic field to safely apply heat and pressure to trigger fusion, which is being adopted by the ITER project in Paris and a few others. Indeed, researchers believe that “magnetic confinement fusion holds some real promise.”
For sure, the encouraging result of NIF experiment and the good progress reported from ITER on the magnetic confinement fusion method will trigger further research leading to more breakthroughs. It is of course, hard to say when this research will yield a fusion-energy future ... but be it in 20, 50 or 100 years, whenever it gets ready, it would be an incredible technology for mankind. So, let us hope scientists will soon come out “vijayisyasi”—victorious.
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More by : Gollamudi Radha Krishna Murty