I recently read Chris Wallace’s Countdown 1945 about the building and deployment of the atomic bombs dropped on Hiroshima and Nagasaki in World War II. Those bombs (the uranium based Little Boy and the plutonium based Fat Man) drew their explosive energy from nuclear fission. "Fission" refers to the splitting apart of atoms.
Fission is still in use today - it's the reaction that powers nuclear power plants. There is however another atomic process that releases vast energy, and it’s called nuclear fusion. Whereas fission reactions split atoms apart, fusion reactions fuse atoms together. Nuclear fusion is often acknowledged as the process that powers our sun and other stars.
Fusion has been considered impractical to use as an energy source because it requires such tremendous pressures and temperatures to cause atoms to fuse that it is difficult to sustain fusion processes. However, fusion continues to be the focus of much research as it has much potential as a “clean” energy source, and as a result we are getting closer to the day when fusion may yet become a reliable source of power.
My "fun facts" may be more geeky than fun - I'll leave that to you to decide. But without further ado, here are 10 possibly fun facts about nuclear fusion:
Clean and Powerful - Fusing atoms together can release as much as 4 million times the amount of energy as burning coal or gas, and 4 times as much as nuclear fission. Moreover, fusion reactions don’t emit greenhouse gases, nor do they leave long-lived radioactive materials behind. These are just a few of the advantages of fusion as an energy source.
Environment is Key - To achieve nuclear fusion you must have the right environment, and the right environment is a plasma - an ionized state of matter where electrons separate from the nuclei of their atoms. Creating a plasma environment is what requires the high temperatures and pressures mentioned above.
How to Hold the Hot Potato - Getting to a plasma state requires temperatures in the millions of degrees, much hotter than can be contained by any material vessel. Instead, scientists use magnetic fields to hold hot plasma in place using whats called a tokamak device.
A Plasma State of Mind - Plasma is not a state of matter we are used to thinking about. Everyone is familiar with solids, liquids and gases. But scientists estimate that up to 99% of the known universe is made up of matter in a plasma state. Lightning, the Aurora Borealis, and neon tubes are all earthbound examples of plasmas.
First Thoughts - It was British astrophysicist Arthur Eddington who first suggested that stars draw their energy from the fusion of hydrogen into helium back in 1926.
First Efforts - It wasn’t until the 1950s that efforts began to try to achieve fusion here on Earth. It was Soviet scientist Lev Artsimovich who came up with the tokamak concept to contain a fusion reaction.
Weaponized - Fusion reactions have been weaponized, and the weapons are referred to as thermonuclear or hydrogen bombs. The first thermonuclear bomb was called Ivy Mike, detonated by the US in 1952 on an atoll of the Marshall Islands.
World's First - The world’s first controlled release of fusion power was achieved at the Joint European Torus (JET) in Oxfordshire, UK. The “torus” is the shape of the plasma contained in the facility’s tokamak.
Most Recent - South Korea’s KSTAR facility has just announced (December 28,2020) that it has set a world record by holding a plasma at a temperature of over 100 million degrees Celsius for 20 seconds.
Smaller Future? - Both JET and KSTAR are very large machines. In 2018, the Massachusetts Institute of Technology (MIT) announced it was partnering with a private company to build a smaller device with superconducting magnets, called SPARC. If the promise of SPARC is fulfilled, it could become the first nuclear fusion device to demonstrate a “net energy gain”, i.e. that produces more power than it consumes.