In Spider-Man 2, Dr. Otto Octavius aims to provide a source of renewable energy through a fusion

Deuterium is hydrogen-2 (also written as ²H or D), an isotope (or form) of hydrogen with one proton and one neutron.  Deuterium is stable, so it doesn’t decay.  Only 0.0115% of natural hydrogen is made up of deuterium.  The rest is protium (hydrogen-1, or ¹H), which is a stable isotope of hydrogen with a single proton and no neutrons.

Tritium is just another name for hydrogen-3 (also written as ³H or T), a radioactive isotope of hydrogen containing one proton and two neutrons.  Tritium has a half-life of 12.32 years, turning into helium-3 by undergoing beta decay.  Only trace amounts of tritium are found in nature.

Tritium and deuterium can undergo nuclear fusion, a process in which two or more nuclei are combined to create one or more different nuclei and subatomic particles such as protons and neutrons.  Depending on the fusion rea*ction, energy is either released or absorbed.  In the deuterium-tritium fusion rea*ction, the protons and neutrons recombine to create helium-4 (⁴He) and a neutron.  The rea*ction also releases 17.6 MeV (Mega electron-volts) of energy.

²H + ³H  →  ⁴He + ¹n + 17.6 MeV

The nuclei involved in this rea*ction contain positive protons and neutral neutrons- hence the nuclei are positive and repel each other and you can’t just easily stick them together.  In order to overcome this, fusion rea*ctions require a high density and high temperature environment.  At these incredibly high temperatures, electrons separate from the nuclei, forming a “soup” of positively charged nuclei and ions and negatively charged electrons.  This soup is called plasma.  It’s difficult to make plasma for fusion.  Some possible m*ethods involve compressing the fuel, pushing an electric current through the fuel, hitting the fuel with high energy neutral particles, or using a laser to add heat.

Furthermore, plasma can be challenging to control, as it acts like a gas and will expand to fill available space.  This is a problem because the plasma needs to be packed in closely to maintain a high enough density, allowing the deuterium and tritium to more easily interact in a very confined space.  The plasma is also incredibly hot– around 100 million degrees Celsius, or 180 million degrees Fahrenheit- meaning it could burn through or damage the holding vessel if it’s not confined.  Because plasma is influenced by electric and magnetic fields, it can be contained using strong magnetic fields.  It may also be possible to induce, create, and contain plasma through high-powered lasers.  In theory, these lasers would focus onto the surface of a pellet of deuterium-tritium fuel.  The outer layer of the pellet would heat and then explode, forcing an inward implosion of the pellet that then compresses and heats the inner part of the pellet.  The resulting conditions would cause fusion rea*ctions.

Unfortunately, successful nuclear fusion for power hasn’t been achieved yet.  While scientists have been able to perform nuclear fusion, is still take more power to start fusion rea*ctions than the energy produced.  For example, the National Ignition Facility at Lawrence Livermore National Laboratory in California has been trying to achieve laser-b*ased self-sustaining fusion rea*ctions for a decade.  The International Thermonuclear Experimental Reactor is currently building a magnetic fusion device in France, but it’s not planned to be powered up until 2025.

Still, the energy production possible from deuterium-tritium fusion is enticing.  The fuel is abundant– deuterium can be extracted from seawater and tritium can be produced from lithium found the Earth’s crust.  It also doesn’t release carbon dioxide or other greenhouse gases like those produced from burning fossil fuels.  Unlike traditional nuclear power, which relies on the fission or break-up of uranium nuclei, no long-lived radioactive nuclear waste is produced.  Nuclear fusion power would also avoid nuclear meltdowns (such as Chernobyl or Fukushima) in the case of an accident, as any problem would cause the plasma to cool and cease fusion rea*ctions.  If the technology could be worked out, nuclear fusion could be part of the energy landscape.

Clearly, we just need mechanical arms to help with the fuel.  I guess we’ll just have to be prepared to deal with a super villain.