Nuclear fusion occurs when two light atomic nuclei merge to create a heavier nucleus, releasing large amounts of energy. These fusion reactions happen in plasma, which is a hot, charged gas made up of positive ions and free electrons, having unique properties different from solids, liquids, or gases.
Nuclear fusion is the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy.
Fusion reactions take place in a state of matter called plasma, a hot, charged gas made of positive ions and free-moving electrons with unique properties distinct from solids, liquids, or gases.
Credit: Third Party Reference
The sun, like other stars, gets its energy from nuclear fusion. To fuse, nuclei must collide at very high temperatures, about ten million degrees Celsius. This high heat gives them enough energy to overcome their electrical repulsion.
When they get close enough, the nuclear force can overcome this repulsion, allowing fusion to occur. For this to happen, the nuclei need to be in a small space to increase collision chances. In the sun, the intense pressure from its gravity creates the right conditions for fusion.
Why are the scientists studying fusion energy?
Ever since the theory of nuclear fusion was understood in the 1930s, scientists and, increasingly, also engineers, have been on a quest to recreate and harness it. That is because if nuclear fusion can be replicated on Earth at an industrial scale, it could provide virtually limitless clean, safe, and affordable energy to meet the world’s demand.
Fusion could generate four times more energy per kilogram of fuel than fission (used in nuclear power plants) and nearly four million times more energy than burning oil or coal.
Most of the fusion reactor concepts under development will use a mixture of deuterium and tritium, hydrogen atoms that contain extra neutrons. In theory, with just a few grams of these reactants, it is possible to produce a terajoule of energy, which is approximately the energy one person in a developed country needs over sixty years.
Fusion fuel is abundant and easy to find: deuterium comes cheaply from seawater, and tritium can be made by using fusion-generated neutrons with plentiful lithium. These fuel sources could last millions of years. Future fusion reactors are safe and won’t create high levels of long-lasting nuclear waste.
Credit: Third Party Reference
Additionally, since starting and keeping the fusion process going is challenging, there’s no risk of a runaway reaction or meltdown. Fusion can only happen under very specific conditions, so if there’s an accident or system failure, the plasma will quickly lose energy and stop, preventing any serious damage to the reactor.
Importantly, nuclear fusion — just like fission — does not emit carbon dioxide or other greenhouse gases into the atmosphere, so it could be a long-term source of low-carbon electricity from the second half of this century onwards.
Hotter than the sun
While the sun’s gravity helps with fusion, without it, we need temperatures higher than the sun’s—over 100 million degrees Celsius on Earth—to fuse deuterium and tritium. We must also control pressure and magnetic forces to keep the plasma stable and maintain the fusion reaction long enough to generate more energy than we use to start it.
While conditions that are very close to those required in a fusion reactor are now routinely achieved in experiments, improved confinement properties and stability of the plasma are still needed to maintain the reaction and produce energy in a sustained manner.
Credit: Third Party Reference
This ongoing challenge requires not only advanced theoretical understanding but also extensive practical experimentation. Scientists and engineers from all over the world continue to develop and test new materials that can withstand extreme temperatures and pressures, while also focusing on innovative cooling methods to manage the heat generated during the fusion process.
Additionally, the design of new technologies, such as magnetic confinement systems and inertial confinement techniques, is crucial to achieving net fusion energy. Collaborative international efforts, including large-scale experiments like ITER, aim to push the boundaries of current knowledge and propel humanity towards a cleaner, virtually limitless energy source for the future.
Where do we stand on fusion technology development?
Nuclear fusion and plasma physics research are carried out in more than 50 countries, and recently, researchers have finally achieved scientific energy gain in a fusion experiment for the first time. Experts have come up with different designs and magnet-based machines in which fusion takes place, like stellarators and tokamaks, but also approaches that rely on lasers, linear devices, and advanced fuels.
The rollout of fusion energy will rely on global partnerships and collaboration, as well as the speed at which the industry can develop and validate new fusion technologies. It is also crucial to build the necessary nuclear infrastructure, including requirements, standards, and best practices, to support this future energy source.
Credit: Third Party Reference
After 10 years of design, site preparation, and global manufacturing, the assembly of ITER, the largest international fusion facility, began in France in 2020. ITER is a global project that aims to show that fusion energy can be produced and to validate technology for future demonstration fusion power plants, known as DEMOs. The first experiments at ITER are expected to begin in the latter half of this decade, with full-power experiments planned for 2036.
Experts agree that electricity-producing fusion power plants could be operational by 2050, while privately funded companies are also advancing fusion power concepts potentially sooner.
Reference: https://www.iaea.org/newscenter/news/what-is-nuclear-fusion
