Explained: US Scientists Achieve Nuclear Fusion Breakthrough For 2nd Time, What Is It And Why Does It Matter?

Nuclear fusion is the process that powers the Sun and other stars. Scientists have been working to achieve it for deuces. It can potentially provide almost limitless clean energy.


Conventional nuclear energy reactors use nuclear fission. On the other hand, nuclear fusion is advanced method to generate nuclear energy that scientists are working on. (Representative Image)

Scientists in the United States have achieved net gain in nuclear fusion for the second time.

Net gain means that the energy produced as a result of nuclear fusion was more than the energy used to create that fusion. 

The nuclear fusion is one of the two methods to produce nuclear energy. The conventional method is the nuclear fission that's in use for decades. For decades, however, scientists have been working on nuclear fusion that's the process the Sun uses to generate power. 

If successfully produced at scale, the nuclear fusion has the potential to provide almost limitless clean energy. 


Here we explain what's nuclear fusion, what the scientists have achieved so far, and what are the applications and possibilities if nuclear fusion is achieved at scale.

What is nuclear fusion?

Nuclear energy is produced by two methods called nuclear fusion and nuclear fission.

Nuclear fission has been used to generate nuclear energy for eight decades now. It was first achieved in 1942 as part of the Manhattan Project, the US program of the development of the atomic bomb in World War II. It is the conventional method of produce nuclear energy. Nuclear fusion, on the other hand, is the process that scientists are working on for decades. It has been demonstrated but, unlike nuclear fission, has not been produced on scale. 


In nuclear fission, a neutron (part of an atom) slams into a larger atom and splits it into two smaller atoms. These two smaller atoms produced after the slamming are called fission products. This act of 'fission' creates lots of energy. 

"When each atom splits, a tremendous amount of energy is released...The energy released by fission in these reactors heats water into steam. The steam is used to spin a turbine to produce carbon-free electricity," says US Department of Energy (DoE). 

Nuclear fusion, on the other hand, follows the opposite approach. In this method, two atoms slam together to form a heavier atom. They 'fuse' into this bigger atom.

The US DoE says a common example of nuclear fusion is when two hydrogen atoms fuse to form one helium atom.

"This is the same process that powers the sun and creates huge amounts of energy—several times greater than fission. It also doesn’t produce highly radioactive fission products," says US DoE.

What have the scientists achieved now?

The first successful demonstration of nuclear fusion was done in December 2022 when scientists achieved 'net gain' status.

The net gain means that the energy produced from nuclear fusion was more than the energy used to create that fusion. 

On July 30, scientists at the US-based Lawrence Livermore National Laboratory (LLNL) achieved such net gain for the second time, reported Reuters, adding that the energy produced was also more than the first time.


In December 2020, scientists used  2.05 megajoules of energy through lasers to cause nuclear fusion which produced 3.15 megajoules of energy. 

The results from the July 30 experiment are still being analysed, reports Reuters. 

What are the uses of nuclear fusion?

Nuclear fusion has multiple advantages over nuclear fission currently in use. 

Firstly, nuclear fusion produces much more energy than nuclear fusion. 

Secondly, nuclear fusion does not produce radioactive waste to the extent of nuclear fission.

"Nuclear fission produces radioactive waste, which can be dangerous and must be stored safely - potentially for hundreds of years. The waste produced by nuclear fusion is less radioactive and decays much more quickly," says BBC News. 


Thirdly, nuclear fusion has the potential of being an almost limitless source of clean energy. This can help with the climate crises the world is facing. 

"Scaling the technology up to light highways, heat showers, and run air conditioners for thousands of households will require many more ignition events like this, each revealing new ways to make the process more efficient and manageable. Fusion power based on easily harvested hydrogen isotopes, if it can be achieved, would theoretically unlock virtually limitless amounts of energy unfettered by the radioactive waste problem of fission and the greenhouse-gas burden of carbon combustion," says Science Alert. 


Such a situation, however, is far for now as energy produced from fusion so far is minimal. Moreover, only two successful net gain experiments have been conduced. Scaling up nuclear fusion remains a challenge.