By Prateek Tripathi
Ever since their conception in the 1970s, fusion reactors have remained a long-elusive goal for humankind. With the ever-growing scarcity of fossil fuels, coupled with their propensity for greenhouse gas emissions, fusion reactor technology offered a way out and came to be viewed as the holy grail for clean energy production. However, it faced significant obstacles along the way and, for a while, it seemed as if humanity had reached an impasse. The recent breakthrough at the National Ignition Facility (NIF) has rejuvenated the hope of achieving this long-sought goal, and may hold the key to finally achieving a reliable source of clean energy in the times to come.
What is nuclear fusion?
Nuclear fusion is the process employed by nature to harness energy within stars such as the Sun. It is the most efficient known form of energy production in the universe, producing four times more energy than a standard Uranium-based fission reaction, minus the radioactive waste. A fusion reaction occurs when two atoms with lighter nuclei combine to form an atom with a heavier nucleus. The mass of the resulting atom is slightly lower than the combined mass of the constituent atoms, and this lost mass is released in the form of energy as per Einstein’s mass-energy equivalence relation (E=mc2). Typically, the two lighter atoms are slightly bulky variants (isotopes) of the Hydrogen atom i.e. Deuterium (D) and Tritium (T), with a Helium atom being the end product.
For a fusion reaction to be viable for energy production, it has to be carried out in a controlled and sustainable manner, so that the energy released can be used to say, rotate a turbine which would subsequently generate electricity.
The efficiency of a fusion reaction is given by a quantity called the Gain defined as:
The objective is to achieve a gain greater than 1. However, this has been notoriously difficult to implement practically. This is primarily because to achieve fusion, the two constituent nuclei must first combine, which requires overcoming their mutual electrostatic repulsion stemming from the fact that they are both positively charged. This has given rise to different approaches to achieving fusion.
Types of fusion reactors
In the case of the Sun, the atoms get stripped of their electrons and converted into positively charged ions due to extremely high temperatures, resulting in a dense soup of ions and electrons called a plasma. In these conditions, it is possible for the ions to acquire a high enough velocity (kinetic energy) to overcome their electrostatic repulsion and allow fusion to occur. This is essentially the process used in fusion reactors, with the difference being that now the extreme temperatures must be created artificially. There are two primary ways of achieving this.
- Magnetic confinement
Magnetic Confinement Fusion (MCF) uses a magnetic field to contain the plasma, which prevents the particles from hitting the reactor walls which would otherwise cause them to slow down. The most effective shape for such reactors turns out to be that of a doughnut or toroid. Tokamaks and Stellarators are some examples of such toroidal reactors. Most of the reactors in the past were based on this technology.
- Inertial confinement
In Inertial Confinement Fusion, high-energy laser beams are focused onto a pellet of the fuel (D-T), which creates the extreme temperatures required for fusion inside it. The outer mass of the pellet explodes and is responsible for confining the reaction, in place of the magnetic field in case of MCF.
Some other variants of reactors are also in existence such as those which use a combination of these two methods (Magnetised Target Fusion) and those that combine fission with fusion (Hybrid Fusion).
The breakthrough at NIF
Despite devising some ingenious methods to overcome the practical limitations of achieving fusion, the hopes of reaching a net gain remained fleeting. In December 2022, however, the NIF at the Lawrence Livermore National Laboratory was finally able to achieve “breakeven,” or a net positive energy gain. Later, in July 2023, it was able to replicate its efforts, but now with an even bigger gain. In both cases, inertial confinement was employed, in which laser beams were fired at D-T pellets. This has turned out to be a truly monumental achievement and it has reinvigorated interest in a technology that was perceived to be lying stagnant for a long time.
According to the Fusion Industry Association’s 2023 Global Fusion Industry Report, global investment in the fusion industry has risen to US$6.2 billion, which is US$1.4 billion more than the previous year. The US Department of Energy has also recently announced an investment of US$46 million into eight startups developing nuclear fusion power plants. It can thus be concluded that the development at NIF has bolstered investment in the field.
While this is certainly cause for celebration, it also comes with a huge caveat. The energy gain cited here only refers to the gain strictly from the reaction itself. It does not account for the input energy required to operate the laser nor for the other equipment being used to carry out the reaction. When all these factors are accounted for, we get the “total gain,” which, as it turns out, is still significantly lower than 1. To be viable for commercial operation, the NIF needs to raise its output by at least 100,000 percent. So, while this is most definitely a breakthrough in fusion reactor technology, there are still significant practical hurdles on the way to commercially feasible power generation.
India has emerged as a major player in fusion technology and has been one of the pioneers in its development. The Plasma Physics Programme was initiated by the Government of India in 1982 to conduct research on MCF, which later evolved into the Institute for Plasma Research (IPR) in 1986 and led to the creation of India’s own indigenous tokamak, ADITYA, in 1989. Subsequently, it also developed a larger semi-indigenous tokamak called the Steady State Superconducting Tokamak (SST-1) which was fully commissioned in 2013. IPR has also revealed its plans for a successor, the SST-2, due in 2027.
In 2005, India became the seventh member to join the International Thermonuclear Experimental Reactor (ITER) project, a global initiative attempting to build the world’s largest tokamak reactor. ITER-India has been set up under the supervision of IPR and is responsible for fulfilling India’s commitments to the project. It has already provided the world’s largest cryostat, a vacuum application stainless steel vessel, to house the reactor, along with a host of other equipment.
Private investment is the key area where India lags behind, owing to the Atomic Energy Act, 1962, which puts the brunt of developing and running nuclear power stations on the government. Domestic private companies are allowed only as “junior equity partners,” with their role being limited to supplying components and construction. However, a government panel recently convened by the NITI Aayog has recommended overturning the ban on foreign investment in the nuclear power industry and allowing greater participation by domestic private firms.
A golden opportunity for India
The commercial production of energy via fusion reactors may be at least a decade off, however, it provides India with a golden opportunity to take advantage of the novelty of the situation. The NIF experiment has opened up a new avenue for achieving nuclear fusion through the means of inertial confinement and it would be fruitful for India to take notice and invest in this technology since it is clear that this is where its future lies. It would not only offer a reliable substitute for fossil fuels in the future but also ensure it reaches its goal of achieving net-zero carbon emissions by 2070 well ahead of time.
About the author: Prateek Tripathi is a probationary Research Assistant, Centre for Security, Strategy and Technology at Observer Research Foundation
Source: This article was published by the Observer Research Foundation
 A tokamak is a machine designed to confine plasma using magnetic fields. It is in the shape of a torus or a donut. The term “tokamak” comes from a Russian acronym which means “toroidal chamber with magnetic coils.”