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Nuclear fusion is an attempt to replicate the processes of the Sun on Earth. It differs significantly from nuclear fission, which has been our only way of getting electricity from atoms since the 1950s. The BBC website in a report on Nuclear Energy by Matt McGrath on November 6, 2019 says prospects for developing nuclear fusion as a feasible source of energy have significantly improved. The UK government has recently announced an investment of £200m to deliver electricity from a fusion reactor by 2040. Private companies and governments have told the BBC they aim to have demonstration models working within five years. But huge hurdles remain, say critics.

With the price of wind and solar continuing to drop, experts say these existing renewables might offer a more economical and timely method of tackling climate change and generating energy than an unproven technology like fusion. Fission has proven to be hugely expensive. It generates large amounts of radioactive waste and raises serious concerns about safety and the proliferation of weapons.

Fusion is the process that drives our Sun. Every single second, millions of tonnes of hydrogen atoms crash together in the tremendous temperatures and pressures of our parent star. This forces them to break their atomic bonds and fuse to make the heavier element, helium.

For decades, researchers have been trying to replicate this process on Earth, or 'build the Sun in a box” as one physicist dubbed it. The basic idea is to take a type of hydrogen gas, heat it to more than 100 million °C until it forms a thin, fragile cloud called a plasma, and then control it with powerful magnets until the atoms fuse and release energy. Potentially, it can generate power that is low carbon, with much smaller amounts of waste. It also comes without the danger of explosions. To deliver the fusion concept, countries have focused their energies on a major international co-operative effort called ITER. The BBC asks the question is it '.. a giant step forward or a white elephant?”

The International Thermonuclear Experimental Reactor (ITER) project involves 35 countries and, right now, it is constructing a huge test reactor in southern France. The plan is to have the first plasma generated in 2025. However, getting from this step to producing energy is extremely difficult. ITER has also been beset by long delays and budget overspend which means it is unlikely to have a demonstration fusion power plant working even by 2050. 'One of the reasons that ITER is late is that it is really, really hard,” said Prof Ian Chapman, chief executive of the UK Atomic Energy Authority. 'What we are doing is fundamentally pushing the barriers of what's known in the technology world. And of course you reach hurdles and you have to overcome them, which we do all the time and ITER will happen, I am completely convinced of it.”

Until ITER is up and running in 2025, the UK based Joint European Torus (Jet) remains the world's largest fusion experiment. It has secured EU funding until the end of 2020, but what happens after that, and the participation of the UK in ITER after Brexit remains unclear. To give some sense of certainty, the UK government recently announced £220m for the conceptual design of a fusion power station by 2040. Over the next four years, researchers based at Culham in Oxfordshire will develop designs for a fusion power plant called Step or Spherical Tokamak for Energy Production.

The most widely known approach to making fusion happen involves a doughnut shaped vacuum chamber called a Tokamak. Hydrogen gas is heated to 100 million °C at which point it becomes a plasma. Powerful magnets are used to confine and steer the plasma until fusion occurs. In the UK, researchers have developed a different form of Tokamak, that more resembles an apple core than a doughnut. Called a Spherical Tokamak, it has the advantage of being more compact, potentially allowing future power plants to be located in towns and cities.

'If you look at some of the very big units, the big machines that we are looking at, just finding geographically somewhere to put them is difficult,” said Nanna Heiberg from the UK Atomic Energy Authority. 'What you really want to do is put them close to where the energy is required. And so if you can do them in a much smaller footprint, you can put them closer to the users and you can put more of them around the country for example.”

While governments are wrestling with ITER, many are also driving ahead with their own national plans. China, India, Russia and the US among others are working on developing commercial reactors.

As well as the UK government putting cash in, the European Investment Bank is pumping hundreds of millions of euros into an Italian programme to produce fusion energy by 2050. But perhaps the major excitement comes from private companies. They are usually smaller, nimbler, and they develop by making mistakes and learning from them quickly. There are now dozens of them around the world, raising funds and pushing forward often with different approaches to fusion than that seen in ITER and in the UK.

First Light: This company originated in the University of Oxford and was founded specifically to address the urgent need to decarbonise the global energy system. Their idea involves firing a projectile at a target that contains hydrogen atoms. The shockwave from the impact of the projectile creates a shockwave that crushes the fuel and briefly this reaction will produce plasma that is hotter than the sun and denser than lead. Commonwealth Fusion Systems: A private company created by former Massachusetts Institute of Technology (MIT) staff, CFS has raised significant funding of over $100m. It is focusing on developing a Tokamak system but its key innovation is in superconducting magnets. They hope to build powerful enough magnets so they can build smaller and cheaper Tokamaks to contain the plasmas required to generate fusion.

TAE Technologies: With backing from Google and other high tech investors, this California-based company is using a different mix of fuel to develop smaller, cheaper reactors. They want to use hydrogen and boron as both elements are readily available and non-radioactive. Their prototype is a cylindrical colliding beam fusion reactor (CBFR) that heats hydrogen gas to form two rings of plasma. These are merged and held together with beams of neutral particles to make it hotter and last longer.

US Navy: Worried about how to power their ships in the future, the US Navy has filed a patent for a 'plasma compression fusion device”. The patent says that it would use magnetic fields to create 'accelerated vibration and/or accelerated spin”. The idea would be to make fusion power reactors small enough to be portable. There's a lot of skepticism that this approach will work.

One of the main challengers with ambitions to make fusion work is a company based in British Columbia, Canada called General Fusion. Their approach, which has gathered a lot of attention and backing from the likes of Amazon's Jeff Bezos, combines cutting edge physics with off the shelf technology. They call their system 'magnetised target fusion”.

Despite the hopes, no one to date has managed to get more energy out of a fusion experiment than they have put in. Most experts are confident the idea will work, but many believe that it is a matter of scale. To make it work, you have to go large. 'I think fusion needs resources to really make it work,” said Prof Ian Chapman from UKAEA. 'You could do that within a company or a country but you really need to have the requisite scale and resources. When ITER works, and I say when, not if, it will be a step change for fusion and you will see massive investment come into the field.”

A relevant question is will renewable energy make fusion redundant? In 2018, the IPCC reported that emissions of CO2 need to be reduced by 45% by 2030 to keep the rise in global temperatures under 1.5°C. Getting to that point requires a rapid decarbonisation of the energy sector. The UK has committed to Net Zero emissions by 2050 which will require the deployment of wind and solar on a massive scale. Some argue this should be a greater priority for Britain, rather than spending large sums on experimental fusion reactors. 'The cost of renewables has shot down while the cost of the world fusion project, ITER, has gone up and it now looks very unlikely they will be able to compete without new ideas,” said Sir Chris Llewellyn Smith, a one time chair of the ITER council and a respected British physicist. 'I don't think this means we should give up on fusion, there are ways it could become cheaper but it is not going to be there immediately when we need it in the UK at least.”

Others involved in the fusion industry take a different view. 'If you're a country like Malaysia, that has a high carbon intensity of its energy system, and you're trying to move away from coal, there's not a lot of options today,” said Chris Mowry, General Fusion's chief executive. 'This is the type of application we're focused on. And even in countries like Canada, which have a fair amount of renewables, it can never be 100% renewables. And so we need a carbon free source of energy that can complement renewables in the future.”

The Center for Nuclear Science and Technology Information website says that Nuclear Fusion is a nuclear process, where energy is produced by smashing together light atoms. It is the opposite reaction of fission, where heavy isotopes are split apart. Fusion is the process by which the sun and other stars generate light and heat. It's most easily achieved on Earth by combining two isotopes of hydrogen: deuterium and tritium. Hydrogen is the lightest of all the elements, being made up of a single proton and an electron. Deuterium has an extra neutron in its nucleus; 364 Fifteen Shades of Climate Energy 365 it can replace one of the hydrogen atoms in H2O to make what is called 'heavy water.” Tritium has two extra neutrons, and is therefore three times as heavy as hydrogen. In a fusion cycle, tritium and deuterium are combined and result in the formation of helium, the next heaviest element in the Periodic Table, and the release of a free neutron. Deuterium is found one part per 6,500 in ordinary seawater, and is therefore globally available, eliminating the problem of unequal geographical distribution of fuel resources. This means that there will be fuel for fusion as long as there is water on the planet.

Scientists from the Max Planck Institute for Plasma Physics in Greifswald, Germany, have demonstrated that it is possible to superheat hydrogen atoms to form a plasma of 80 million °C using a machine called the Wendelstein 7-X stellarator. The plasma forms the basis for nuclear fusion, in which hydrogen atoms collide and their nuclei fuse to form helium atoms – a process which lets off energy and is similar to what happens in our sun.

What is Fusion Power? Let's take a look at a fusion reaction. As deuterium and tritium fuse together, their component parts are recombined into a helium atom and a free neutron. As the two heavy isotopes are reassembled into a helium atom, you have ‘extra' mass leftover which is converted into the kinetic energy of the neutron, according to Einstein's formula: E = mc2 . For a nuclear fusion reaction to occur, it is necessary to bring two nuclei so close that nuclear forces become active and glue the nuclei together. Nuclear forces are small-distance forces and have to act against the electrostatic forces where positively charged nuclei repel each other. This is the reason nuclear fusion reactions occur mostly in high density, high temperature environments.

From the website Climatewire and in the E+E News dated July 24, 2019, as reported in the Scientific American, Nathanial Gronewold said that The International Thermonuclear Experimental Reactor is set to launch operations in 2025. The International Thermonuclear Experimental Reactor is under construction in southern France.

A multinational project to build a fusion reactor cleared a milestone yesterday and is now 6½ years away from 'First Plasma,” officials announced. Dignitaries attended a components handover ceremony at the construction site of the International Thermonuclear Experimental Reactor in southern France. The ITER project is an experiment aimed at reaching the next stage in the evolution of nuclear energy as a means of generating emissions-free electricity. The section recently installed–the cryostat base and lower cylinder–paves the way for the installation of the tokamak, the technology design chosen to house the powerful magnetic field that will encase the ultra-hot plasma fusion core.

'Manufactured by India, the ITER cryostat is 16,000 cubic metres,” ITER officials said in a release. 'Its diameter and height are both almost 30 metres and it weighs 3,850 tons. Because of its bulk, it is being fabricated in four main sections: the base, lower cylinder, upper cylinder, and top lid.” The entire project is now 65% complete, the officials said. The world's first commercial-scale fusion reactor project is on track to officially launch operations at the end of 2025, said spokeswoman Sabina Griffith, but it will take at least a decade to fully power up the facility. 'The date for First Plasma is set; we will push the button in December 2025,” Griffith said. 'It will take another 10 years until we reach full deuterium-tritium operations.” Thirty-five nations are cooperating on the project to bring fusion power to the masses.

Achieving controlled fusion reactions that net more power than they take to generate, and at commercial scale, is seen as a potential answer to climate change. Fusion energy would eliminate the need for fossil fuels and solve the intermittency and reliability concerns inherent with renewable energy sources. The energy would be generated without the dangerous amounts of radiation that raises concerns about fission nuclear energy. Officials say the ITER nuclear fusion reactor is poised to be the most complicated piece of machinery ever built. It will contain the world's largest superconducting magnets, needed to generate a magnetic field powerful enough to contain a plasma that will reach temperatures of 150 million °C , about 10 times hotter than the centre of the sun.

'We will see the arrival of the first major Tokamak components like the first PF Coil from China (a European contribution), a Vacuum Vessel sector from Korea and first TF coils (from Europe and Japan) in autumn,” Griffith said in an email. 'This will lead us to the official start of assembly in spring next year.”