What is Nuclear Fusion?
Nuclear Fusion creates loads of energy. In technical terms, two lighter atoms join (or fuse) together in extreme temperatures to make one heavy atom. When you look at the sun or the stars in the sky, that is exactly what you see, nuclear fusion in action.
The fusion of the nuclei of two atoms of Hydrogen results in the creation of Helium. This may not sound too exciting, but there will be a release of energy with any nuclear reaction. In the case of nuclear fusion, a tremendous amount of energy. Amazingly nuclear fusion produces 3–4 times that of nuclear fission. As a comparison, nuclear fission results in 1.2 million times the energy of coal or TNT.
Nuclear fusion is already used within thermonuclear bombs in combination with nuclear fission. However, the holy grail of the nuclear industry is to generate electricity using a nuclear fusion reactor. This has been something that has been sought for decades.
Nuclear fusion as an energy source would be such a big step forward. The fuel would be Hydrogen with the waste product helium. This is worlds away from the current fossil or nuclear fuels technologies. There has been some success, and development continues to progress, but there is no solution to this challenge just yet.
KEY TAKEAWAYS
- Nuclear Fusion was first demonstrated in a laboratory in 1932.
- Nuclear Fusion has been just a couple of decades away from commercialisation since 1955.
- Nuclear fusion is the joining (or fusing) of two larger atoms releasing a huge amount of energy in the process.
- The fuel for a nuclear fusion reactors is Hydrogen and the only by-product would be Helium.
- Nuclear fission produces one million times more energy than coal. Nuclear fusion provides 3-4 times more energy than fission.Nuclear Fusion Reactor
Nuclear fusion comes with a promise of a solution to the world’s climate change issues. However, there is one technical hurdle that needs to be overcome. For lightweight atoms to fuse and release the energy, they need to be brought together In millions of degrees of heat.
The goal of a fusion reactor is to achieve fusion plasma. This is an enormous cloud of rolling atoms hotter than the sun. The nuclear plasma needs to be generated and kept under control using less energy than the fusion reactor produces.
As such, fusion power has been ’a couple’ of decades away for almost a century.
There are currently several designs under development, most of which are based on a tokamak design. By utilising a doughnut-shaped design, the tokamak allows the plasma cloud to be confined by magnetic forces. This will allow for the containment of the reaction of two isotopes of Hydrogen at 100,000,000 degrees centigrade. This is known as magnetic confinement.
Other designs include inertial confinement fusion (ICF), Magnetic or electric pinches and inertial electrostatic confinement. They all take more energy to run than they produce. There is optimism that this will change soon.
Where does Nuclear Fusion occur?
Nuclear fusion has an exciting past. It all started in 1932 with the first demonstration of fusion in a Laboratory by Mark Oliphant. Fast forward to 2020, the MAST achieved plasma claiming ‘game-changing’ improvements to fusion technology. The story has yet to conclude. It feels like it is only just beginning.
You can find a timeline of all of the significant occurrences in the lifecycle of fusion reactor development. This can be found on Wikipedia. We have put together a much more concise version of the events below. This should be enough info to inspire you to apply for one of the many roles supporting the pursuit of nuclear fusion reactor technology.
The actual first attempt to make a working fusion reactor was in 1938. However, the NACA Langley Research Center attempt was unsuccessful. The UK’s ZETA device at Harwell claimed fusion in 1958, later withdrawn following the challenge. However, subsequently, in the same year, the first controlled thermonuclear fusion in any laboratory was achieved by Scylla I. However, the pinch approach used by Scylla was abandoned as it was not possible to scale up to produce a reactor.
In the nuclear deterrence arena, 1952 saw the first detonation of a thermonuclear bomb. The bomb released 10.4 megatons of TNT out of fusion fuel. In 1961 the Tsar Bomba was tested by the Soviet Union. At 50 megatons, it remains the most powerful weapon ever dropped.
In 1955, it was first predicted that fusion would be ready for commercial use in just two decades. Homi J. Bhabha made this at that year’s Atoms for Peace. This stirred several countries into action to start fusion programs of their own. The race to first fusion plasma began.
Nuclear fusion was starting to look like an exciting place in the early 1960s. It was not until 1964 that plasma temperatures approximating 40 million degrees Celsius were achieved. The Scylla IV accomplished this at the LANL facility in Los Alamos, New Mexico. In the meantime, in 1960, the concept for inertial confinement fusion (ICF) was published by John Nuckolls.
This was short-lived. At an international meeting in 1965, it was clear that most fusion efforts had stalled. The Soviets showed significant improvements in their toroidal pinch machines, almost identical to the ZETA design. At the same meeting, ZETA reported some strange results. All meaningful designs are losing plasma at too high of a rate to be utilised in a reactor.
Three years later, in 1968, the Soviets claimed temperatures were higher than any other by order of magnitude. This is for their T-3 tokamak, similar to their toroidal pinch machine and ZETA. This is, of course, met with scepticism. However, the Soviets were confident and invited a UK team — “The Culham Five” — to confirm the results. They published their results in late 1969, establishing the results. This led to an increase in tokamak construction all over the globe.
It was not until 1975 that the Princeton Large Torus (PLT) commenced operation. They were quickly setting many records. The PLT surpassed any machines that had gone in the past. These results led to the US DOE providing the funding for a Tokamak Fusion Test Reactor (TFTR) in 1976. The PLT continues to set new records, and in 1978 Princeton was given additional funding to further adapt TFTR with the explicit goal of reaching breakeven.
Commencing design work in 1973, it was completed on time and budget. It was then not until the 1980s that progress of note was made. In 1983 the Joint European Torus (JET), based in Culham, UK, achieved first plasma. The project was the largest magnetic confinement plasma physics experiment ever.
In 1985 the Japanese tokamak, JT-60, achieved first plasma. In 1988 the Tore Supra in Cadarache, France, utilising superconducting magnets, achieved the first plasma. Additionally, in 1988 the concept design for ITER (International Thermonuclear Experimental Reactor) commenced. This will be a successor for JT-60, T-15, JET and TFTR. ITER is a collaboration between many countries across the world.
In 1989 a huge 10 beam NOVA laser at LLNL, California is, completed and produced 120 kilojoules of infrared laster light during a pulse experiment. This year two electrochemists from Utah announced that they had achieved cold fusion. This indicated that they could achieve fusion at room temperature. However, peer reviews of their work found no credit to their claims.
The 1990s provided many successes and developments in the nuclear fusion space. In 1991 the START (Small Tight Aspect Ratio Tokamak) fusion experiment at Fulham achieved a record result adapting the conventional toroidal fusion experiments into a higher spherical design. In 1993 the TFTR successfully produced 10 megawatts of power from a controlled fusion reactor. Then in 1996, utilising actively cooled plasma-facing components, the French Tore Supra generated 2.3 megawatts for 2 minutes.
The JET tokamak produced a world record 16 megawatts of fusion power in 1997. Four megawatts of self-heating was also achieved. Self-heating is an expression regarding a fusion energy gain factor. The ratio of power released by a fusion reactor versus the energy needed to power the reactor is expressed as Q. When Q is greater than 1, the fusion reactor is self-heating.
A momentous decade for nuclear fusion was completed in the news in 1999 that the START experience was to be superseded by MAST (Mega Ampere Spherical Tokamak). In 1998, the Japanese JT-60 tokamak produced a high-performance shear plasma one year later. This is the current world record of a 1.25 Q fusion energy gain factor.
Following all the developments of the 1990s. The first half of the first decade of the new millennia didn’t produce too much to note. There was a little excitement in 2002 when claims were made about small-scale fusion using acoustic cavitation. This will quickly be dismissed. The ITER project finally decided to be sited in Cadarache in France in 2003.
The National Ignition Facility (NIF) is located at the Lawrence LLNL, California. It is a large laser-based inertial confinement fusion (ICF) research device. The back-end of the decade started promisingly with NIF firing its first bundle of light beams. This achieved the highest ever energy laser pulse of 152.8 kJ in 2005.
The following year in 2006, China’s test reactor, the first to use superconducting magnets is completed. It is called EAST (Experimental Advanced Superconducting Tokamak). At the Heavy Ion Fusion (HIF) Symposium in 2010 in Germany, there is a presentation claiming that HIF will be commercial within the decade.
The 2010s brought more development and progression. In 2012 JET announced a breakthrough in controlling instabilities in fusion plasma. The following year EAST records a confinement time of 30 seconds for H-mode plasma thanks to heat dispersal of tokamak wall improvements. Then, in 2014 there is progress in generating more energy than is used to generate fusion. This was achieved at NIF in the US. However, fusion continued to remain to be a couple of decades away.
2015 saw the Stellarator Wendelstein 7-X in Germany achieve first steady-state plasma. This is by utilising a large-scale stellarator design. In the same year, Polywell was present at Microsoft Research. This was a proposed fusion reactor design. It is still in development. However, in 2019 the University of Sydney produced research to show the design in practice is impossible.
In 2016 the Wendelstein 7-X device produced if first hydrogen plasma. Also, in 2015, the ARC (affordable, robust, compact) fusion reactor was announced by MIT. The ARC design utilises a smaller configuration than other designs whilst maintaining a similar magnetic field.
The following year in 2017, there was quite a bit of movement. China’s EAST achieves over 100 seconds of steady-state high confinement plasma. Helion Energy’s plasma machine, The Fusion Engine, goes into operation. The Tokamak Energy ST40 generates its first plasma in the UK. Also, it is announced that the Norman reactor has achieved plasma by TAE Technologies.
The momentum continued in 2018, with TAE Technologies announcing that its fusion reactor had achieved 20 million degrees Celsius. General Fusion begins developing a 70% scale demo that will be ready in 2023. Commonwealth Fusion Systems is provided investment by Eni. The aim is to commercialise SPARC in collaboration with MIT and utilising ARC technology. Also, during the same year, MIT scientists formulate a theory to remove excess heat from compact fusion reactors.
As we approached the present day in 2017, the announcement was made on the STEP (Spherical Tokamak for Energy Production) facility. The UK has made this investment intending to have a fusion facility in 2040, which is just a couple of decades away. Finally, in 2020, the first plasma was achieved at UK’s MAST tokamak in the following year. The MAST is the forerunner to the STEP, and the successful trial is seen as a ‘game-changer’ when it comes to extracting excess heat.
Nuclear Fission vs Fusion
Nuclear Fusion and Nuclear Fission are physical processes that produce energy from atoms. As described above, Nuclear Fusion occurs when lighter particles join (or fuse). Nuclear Fission occurs when a heavy atom is split. Both create loads of energy.
The main difference between Nuclear Fusion and Nuclear Fission are the fuel types, by-products, amount of energy released and technology availability.
Nuclear Energy Fuels Types; Nuclear Fusion uses Hydrogen, whereas Nuclear Fission uses Uranium or Plutonium.
Nuclear Energy By-Products; Nuclear Fusion releases Helium as a by-product. Nuclear Fission results in spent nuclear fuel. This is known as nuclear waste and needs to be stored securely for many years.
The energy release of Nuclear Energy; Nuclear Fission produces energy 1 million times that of another source such as coal. Nuclear Fusion releases 3–4 times that of nuclear fission.
Nuclear Energy technology availability; Nuclear Fission has been in use since the 1950s. There continue to be development work to make the technology safer, more efficient, and reduce production costs. Nuclear Fusion is the holy grail of the nuclear industry. Development has been ongoing since the 1930s. We currently aim to have a nuclear fusion reactor producing electricity by 2040.
Nuclear Fusion is just one area of excitement in the nuclear industry. The industry is welcoming innovations around several exciting applications for the technology.
There has never been a better time to Get Into Nuclear.
