Fusion power

Fusion power is a proposed form of <a href="/facts/Power_generation/Uo6mQQ1T">power generation</a> that would generate <a href="/facts/Electricity/hNC8D65W">electricity</a> by using heat from <a href="/facts/Nuclear_fusion/hP0gLDqj">nuclear fusion</a> reactions. In a fusion process, two lighter <a href="/facts/Atomic_nuclei/orpIm5Xl">atomic nuclei</a> combine to form a heavier nucleus, while releasing energy. Devices designed to harness this energy are known as fusion reactors. Research into fusion reactors began in the 1940s, but as of 2025, no device has reached net power, although net positive reactions have been achieved.
Fusion processes require fuel, in a state of plasma, and a confined environment with sufficient <a href="/facts/Temperature/QyGe4gmj">temperature</a>, <a href="/facts/Pressure/eyc37GRG">pressure</a>, and confinement time. The combination of these parameters that results in a power-producing system is known as the <a href="/facts/Lawson_criterion/aPUrM8Tp">Lawson criterion</a>. In stellar cores the most common fuel is the lightest isotope of <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a> (<a href="/facts/Protium_(isotope)/c3CAg2Pc">protium</a>), and <a href="/facts/Gravity/bqAN7DdQ">gravity</a> provides the conditions needed for fusion energy production. Proposed fusion reactors would use the heavy <a href="/facts/Hydrogen_isotope/c3CAg2Pc">hydrogen isotopes</a> of <a href="/facts/Deuterium/Bv4wfCkw">deuterium</a> and <a href="/facts/Tritium/HWSa6EHy">tritium</a> for <a href="/facts/DT_fusion/SDEJ3Nw0">DT fusion</a>, for which the Lawson criterion is the easiest to achieve. This produces a <a href="/facts/Helium/yRul93TG">helium</a> nucleus and an energetic <a href="/facts/Neutron/oRCM1geb">neutron</a>. Most designs aim to heat their fuel to around 100 million kelvins. The necessary combination of pressure and confinement time has proven very difficult to produce. Reactors must achieve levels of <a href="/facts/Fusion_energy_gain_factor/vBUBhCmH">breakeven</a> well beyond net plasma power and net electricity production to be economically viable. Fusion fuel is 10 million times more energy dense than coal, but <a href="/facts/Tritium/HWSa6EHy">tritium</a> is extremely rare on Earth, having a half life of only ~12.3 years. Consequently, during the operation of envisioned fusion reactors, lithium <a href="/facts/Breeding_blanket/qbtVW4Xu">breeding blankets</a> are to be subjected to <a href="/facts/Neutron/oRCM1geb">neutron</a> fluxes to generate tritium to complete the fuel cycle. 
As a source of power, nuclear fusion has a number of potential advantages compared to <a href="/facts/Nuclear_fission/LfkIylvm">fission</a>. These include little <a href="/facts/High-level_waste/xlqdBT42">high-level waste</a>, and increased safety. One issue that affects common reactions is managing resulting <a href="/facts/Neutron_radiation/LVJhCcwL">neutron radiation</a>, which over time degrade the reaction chamber, especially the <a href="/facts/First_wall/Nkrhuv8v">first wall</a>.
Fusion research is dominated by <a href="/facts/Magnetic_confinement/ThThVDpr">magnetic confinement</a> and <a href="/facts/Inertial_confinement/67Lyy7nb">inertial confinement</a> approaches. MCF systems have been researched since the 1940s, initially focusing on the <a href="/facts/Z-pinch/x90DDvTn">z-pinch</a>, <a href="/facts/Stellarator/HXSJF0Cz">stellarator</a>, and <a href="/facts/Magnetic_mirror/j2BymN1Q">magnetic mirror</a>. The <a href="/facts/Tokamak/kDtb8Bsw">tokamak</a> has dominated MCF designs since Soviet experiments were verified in the late 1960s. ICF was developed from the 1970s, focusing on laser driving of fusion implosions. Both designs are under research at very large scales, most notably the <a href="/facts/ITER/SkpWL87b">ITER</a> tokamak in France and the <a href="/facts/National_Ignition_Facility/76Jz9cBW">National Ignition Facility</a> (NIF) laser in the United States. Researchers and <a href="/facts/Commercial_fusion/3eumWD9N">private companies</a> are also studying other designs that may offer less expensive approaches. Among these alternatives, there is increasing interest in <a href="/facts/Magnetized_target_fusion/X0xwY1CY">magnetized target fusion</a>, and new variations of the stellarator.

Fusion power open-in-new

Fusion power