What exactly is this breakthrough?
Fission and fusion are two different types of nuclear reactions that produce energy. Fission-based power plants have been around since the 1950s, and India has several of its own. But scientists have been working for years to develop a reactor based on nuclear fusion, which is touted as a clean, abundant and safe source of energy that could eventually allow humanity to break its dependence on fossil fuels that are driving a global climate crisis.
Fusion is the same nuclear process that powers the Sun and other stars. It essentially involves two atoms joining or “fusing” together to form an atom of a heavier element. For example, inside the Sun two hydrogen atoms fuse to form one helium atom.
The latest discovery shows that it might eventually be possible to replicate this process in a commercial power plant.
How is fusion better than fission?
Both fission and fusion use the binding energy of protons and neutrons in the nuclei of atoms to release an enormous amount of energy. The main difference between them is that fission is the splitting of a heavy and unstable nucleus into two smaller nuclei while fusion involves joining two light nuclei together.
A nuclear fission reactor uses uranium, which is not commonly found, as fuel. When a uranium atom becomes excited and unstable with exposure to neutron radiation, it splits into smaller atoms of elements like barium and krypton, and releases more neutron radiation, which, in turn, excites and breaks apart more uranium atoms, causing a chain reaction. The energy that is released is used to boil water to produce steam and run turbines for producing electricity.
The biggest problem with fission is that some of its byproducts remain radioactive for tens of thousands of years, and have to be disposed of in special facilities. Also, reactor accidents can release radioactive material into the environment, as happened at Three Mile Island in 1979 and at Chernobyl in 1986.
Nevertheless, nuclear fission now provides about 10% of the world’s electricity from about 440 reactors, as per world-nuclear. org. Over 50 countries use nuclear energy in about 220 research reactors that are also used to make medical and industrial isotopes. With 92 reactors, the US is the world’s largest producer of nuclear power, accounting for over 30% of global nuclear generation of electricity.
Fusion scores over fission because it can yield several times more energy without producing highly radioactive
byproducts. But so far, fusion reactions in the lab have been difficult to sustain because of the tremendous pressure and temperature needed to fuse nuclei together.
A fusion reaction consumes vast amounts of energy because it occurs at temperatures of 100 million degrees Celsius or higher. The only way to make it self-sustaining is to get more energy out than goes in, and to do so continuously instead of for brief moments. Once fusion is commercialised, we would have virtually carbon-free electricity without any radioactive byproducts. It will help in the fight against climate change. Secondly, because nuclear fusion reactors require only universally abundant hydrogen, they could be set up anywhere – unlikefission reactors that require rare radioactive substances like uranium.
Can’t it occur at normal temperatures?
Like the Sun and the stars, the fusion experiment at LLNL used “hot” fusion, employing ultra-high temperatures. However, some scientists have theorised that ‘cold’ fusion is possible at or near room temperature.
In 1989, electrochemists Martin Fleischmann and Stanley Pons reported that their apparatus had produced anomalous heat (excess heat) of a magnitude that was only possible through a nuclear process. They also reported measuring small amounts of nuclear reaction byproducts, including neutrons and tritium. Their small tabletop experiment involved electrolysis of heavy water – water made up of heavier hydrogen atoms – on the surface of a palladium electrode. While their reported results raised hopes of a cheap and abundant source of energy, they could not be replicated.
It could be real in 10 years
Fusion technology has drawn billions in investments from backers, including Jeff Bezos, Bill Gates and Peter Thiel. In recent years it has also won support from sovereign wealth funds, national development banks and venture capitalists. Fusion attracted $2. 8 billion over the past year, compared with around $2 billion over the previous decade. The Fusion Industry Association said more than 93% of companies that responded to its survey believe fusion power will be feeding electricity into power grids by the 2030s.
