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What is Nuclear Fusion? What are the Pros and Cons of Nuclear Energy?

Jun 28, 2021 8:02 AM 6 min read

A common joke in scientific circles is that nuclear fusion is 30 years away - and always will be.

Recently, Canadian energy company General Fusion announced that it would build a nuclear fusion facility in the UK, taking the world one step closer to that much-anticipated fusion future

The company counts Jeff Bezos as an investor. And the potentially $400m project is expected to be completed by 2025.

But what is nuclear “fusion” exactly? Before we get into that, let’s begin at the beginning...

What is Nuclear Power?

It is the generation of energy through the use of nuclear reactions in nuclear reactors. Most reactors today use a process known as nuclear fission, which involves the splitting of enriched uranium atoms. This is achieved by firing neutrons at uranium atoms, which splits the latter and releases more neutrons - which attack other atoms and so on in a contained chain reaction.

Every time an atom splits, it releases energy in the form of heat, which is used to heat water and generate steam, which in turn is made to pass through a series of turbines. Here, heat energy is converted into mechanical energy and thus, electricity is generated.

Besides fission, energy can also be derived from nuclear decay (when an unstable nucleus loses energy via radiation) and nuclear fusion (the opposite of fission, wherein two or more nuclei are combined rather than split).


What are the Pros of Nuclear Power?

As a “clean” energy source, nuclear doesn't emit harmful greenhouse gases like methane or carbon dioxide. More than 470 million metric tonnes (MT) of carbon is avoided each year thanks to nuclear energy. That's the equivalent of removing 100 million cars off the road.

Amongst green energy sources, too, nuclear boasts an upper hand. Unlike wind and hydro power, it is not geographically constrained i.e. It can even be developed by countries not gifted with high velocity wind currents or large water sources. And unlike solar energy, it is not space-intensive.

Nuclear energy is also relatively efficient. Its fuel-to-power output ratio is incredibly high - in fact, a single functioning reactor can meet an average city’s needs.


What are the Cons of Nuclear Power?

Nuclear energy has a waste problem. Uranium mining, processing and reactor processes produce toxic waste that is hard to dispose of. While the bulk of this comprises lightly-contaminated items such as tools and work clothing, the dangers of spent (used) reactor fuel and other radioactive wastes are very much real. If not discarded properly and safely, they can remain radioactive and pose a danger to human health and the environment for thousands of years.

Then there’s the economics of it all. Initial costs are sky-high. Not just for setting up the plant and hiring the expertise required, but also to secure regulatory approval and local consent - both of which are easier said than done.

Also, nuclear isn’t technically a “renewable” energy source. Uranium is a finite resource. Estimates suggest that the world’s uranium reserves may run out in the next eight decades or so.

Nuclear energy is also geopolitically charged. You need to enrich uranium to use it to generate power. But enrichment is the same starting point if you want to build nuclear weapons. This is why some observers worry that some countries (a popular example being Iran) may use civil nuclear programmes to disguise their pursuit of building atomic weapons.

FYI: To be fair, this point is often misconstrued. To generate power, uranium enrichment of only c. 4% is sufficient; to build weapons, enrichment levels above 90% need to be achieved.


The Seeds of Nuclear Reluctance

But above all, nuclear’s biggest Achilles’ heel may be its image problem. The entire process is devised and supervised by humans, and to err is human. But when things go wrong at a nuclear facility, they can go really wrong.

Despite its many advantages - and demerits that could be contained via strict regulation and safety standards - the number of active reactors worldwide has hardly changed since the 1980s. Moreover, a quarter of existing reactors are expected to shut down in the current decade.

This stems from the power anti-nuclear movement around the world, popular distrust of the energy source, and its perceived association with nuclear weaponry.

This is hardly surprising. The deadly Hiroshima and Nagasaki atomic bombings introduced the world to nuclear technology, which has always been viewed with skepticism and fear every since. Cold War-induced nuclear fright drove home that point that “nuclear” was a bad word. Accidents at Three Mile Island and Chernobyl and depictions in popular culture - in movies like The China Syndrome and miniseries like Chernobyl - added nuclear fuel to fire.

FYI: All said and done, it’s important to put things in context. Accidents happen at all energy facilities. In comparison, the “death rate” for nuclear energy is very low. On average, its production kills one person every 14 years, a level comparable to its green peers, and miles lower than coal, oil and gas. Moreover, climatologists found that 1.84 million lives were saved between 1971 and 2009 thanks to nuclear's air pollution benefits.


The Ides of 2011

In the 2000s, as awareness about the climate crisis and the crucial need to reduce carbon emissions spread, there was renewed interest in the nuclear option. Governments began to commission reactors, R&D took off, and a “nuclear renaissance” was predicted.

Then, Fukushima happened. In 2011, a tsunami struck the Pacific coast of Honshu, Japan’s most populous island. This natural calamity scaled the walls of the nuclear power plant in the region and flooded its underground bunkers. But the incident - whilst the most severe nuclear accident since Chernobyl - directly caused only one cancer-related death. The 2,000+ reported deaths at the facility were attributed to the chaotic evacuation.

However, Fukushima was a live television event, and the world watched aghast. Immediately, Germany said it would hasten the closure of its reactors. Italy held a referendum where 94% voted against a proposal to build new plants. China (briefly) suspended its nuclear programme. Elsewhere, anti-nuclear sentiments surged - to such levels that public support for nuclear power is now lower than that for even coal!

FYI: India’s thorium-centric civil nuclear programme involves 22 nuclear reactors, seven plants and a total installed capacity of 6,780 MW. An ambitious 2010 plan to boost capacity to 63 GW was derailed by public protests following the Fukushima accident. But Budget announcements in 2017 sought to reinvigorate the nuclear push with the planned construction of 10 reactor units of 700 MW capacity.


Enter, Fusion

Now, most reactors in the world today employ fission to generate energy. Fusion - where you combine light atoms to make heavier ones - still exists only on paper.

Fusion has a leg-up over fission in two main ways. One, it reportedly generates considerably less waste. And two, it uses hydrogen isotopes instead of uranium, so it removes the cloud of nuclear weaponry from the process.

So why aren't there fusion plans yet? Because it's a difficult process. Nuclei have protons, which are positively charged. Combining two like-charged particles requires a huge amount of energy. This is why fusion reactions usually happen in high-energy the sun. Replicating such cosmic conditions on Earth is challenging to say the least.


Enter, Competition

The gradual liberalisation of the atomic energy sector has seen a proliferation of private-sector competition. This has led to increased interest in fusion as an alternative to fission - and as a way to bring about that elusive nuclear renaissance.

Bezos-backed General Fusion is one of the more promising bets. But there are others, such as TAE Technologies, which has raised $1.1bn, and British firms First Light Fusion and Tokamak Energy.

Governments are not lagging behind. Germany's Max Planck Institute has been in the fusion game for years. The UK's Culham Centre for Fusion Energy plans to open its fusion reactor in 2040. And the France-based International Thermonuclear Experimental Reactor (ITER) entered its assembly phase last year.

FYI: The $20bn ITER project is the world's largest nuclear fusion experiment. It is an international venture, with participating countries including India, China, Russia, Japan, the US and the EU.


The Bottom Line

Everybody wants clean, green, cheap and safe energy sources. Adequately regulated and strictly monitored nuclear power ticks most boxes, if not all. With recent strides in advanced fission reactors and safety standards, nuclear’s future is increasingly becoming a question of political will and popular awareness.

A success in the fusion front - whilst years away - could considerably tilt the scale in nuclear’s favour. As Christofer Mowry, General Fusion’s CEO, likes to say:

Fission is easy to start and hard to stop… Fusion is the opposite.


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