Fusion energy can provide safe, clean, and almost limitless power. Fusion reactions may occur for nuclei lighter than iron. However, they will not fuse unless exposed to extreme temperatures and pressures, such as those found in the interiors of stars. Scientists are looking for a fuel that is easy to produce, store and bring to fusion to create -burning plasmas in experimental power reactors like tokamaks or stellarators. Deuterium/tritium fuel is the best option for fusion reactors. This fuel can reach fusion conditions at lower temperatures than other elements and releases more energy than different fusion reactions.
Tritium and deuterium are hydrogen isotopes, the most abundant element in the universe. Deuterium and tritium are hydrogen isotopes that have one proton. Tritium has two neutrons, while deuterium has one. Protium is the hydrogen isotope with no neutrons. The reaction between deuterium, tritium, and hydrogen creates a helium nucleus with two protons, two neutrons, and one neutron. The reaction releases an energetic neutron. Fusion power plants will convert the energy from fusion reactions to electricity to power homes and businesses.
The nucleus of all hydrogen isotopes only contains one proton, while the number of neutrons is variable. Credit: Image courtesy General Atomics
Deuterium is a common element. Deuterium is found in approximately 1 in 5,000 seawater hydrogen atoms. Deuterium is found in large quantities in our oceans. If fusion power is a reality, one gallon of seawater can produce enough energy to make 300 gallons of gasoline.
Tritium, a radioactive element, is very rare and decays quickly. It has a half-life of 12 years. Tritium can be created by exposing lithium, which is more abundant, to energetic neutrons. A working fusion power station would require enriched lithium to produce the tritium needed to complete the deuterium-tritium cycle. Current R&D efforts focus on developing advanced tritium breeding blankets that use lithium originally extracted from Earth-based sources.
Deuterium-Tritium Fuel Facts
- Deuterium water is 10 percent heavier than regular water. This is why it’s sometimes called “heavy water” or “heavy water.” It can sink to the bottom in a glass of regular water.
- Tritium can be found in many sources on Earth, including natural production through interactions with cosmic rays and energy-producing nuclear fission reactions such as the heavy water CANDU atomic reactor and nuclear weapons test.
- Aneutronic fusion reactions are also of interest to fusion scientists, even though they occur at higher temperatures than those for tritium and deuterium. This avoids potential R&D challenges such as structural material damage by energetic neutrons.
DOE Office of Science: Contributions for Deuterium-Tritium fuel
Part of The Department of Energy Office of Science’s Fusion Energy Sciences (FES) is to develop practical fusion energy sources. FES collaborates with the Advanced Scientific Computing Research program to use scientific computing to understand the effects of ion mass upon various plasma phenomena. Scientists study the impact of ion mass upon plasma confinement, transport, and turbulence at Office of Science user facilities, such as the DIII–D tokamak or the NSTX–U Spherical Tokamak. In the presence of helical magnet fields, scientists also study the confinement of fusion products like helium-ion. The Office of Science Nuclear Physics program is responsible for developing fundamental nuclear science that underpins the understanding of fusion. It creates nuclear reaction databases, generates atomic isotopes, and clarifies aspects of nucleosynthesis.