The ITER project, a collaboration involving 35 nations, is constructing a fusion device in Southern France intended to prove the scientific and technological feasibility of fusion energy. The primary objective is to produce a net energy gain from a sustained burning plasma. The machine is designed to generate 500 MW of thermal fusion power from an input of 50 MW of plasma heating power, achieving a plasma energy gain factor (Q) of 10. This result would represent a critical step in validating the tokamak concept for future commercial power plants, serving as a testbed for integrated technologies, materials science, and operational physics at reactor scale. Source: ITER

At the core of the ITER facility is a massive tokamak, a magnetic confinement device that will contain a plasma of deuterium and tritium. The plasma is projected to reach a temperature of 150 million degrees Celsius, approximately ten times hotter than the core of the Sun. This extreme temperature is necessary to overcome the Coulomb barrier and induce fusion reactions. Confining this superheated plasma requires an immense magnetic field generated by a system of powerful superconducting magnets. The successful operation of these systems is fundamental to achieving the stable plasma conditions required for significant fusion power production. Source: ITER

At the core of the [ITER](/programs/iter) facility is a massive tokamak, a magnetic confinement device that will contain a plasma of deuterium and tritium.

The fuel cycle for ITER will utilize a 50-50 mixture of deuterium and tritium (D-T), selected for its high fusion cross-section at the lowest achievable temperatures in a laboratory setting. Deuterium is abundant in seawater, but tritium is a radioactive isotope with a short half-life that must be produced artificially. While initial operations will rely on an external tritium supply, a key secondary mission for ITER is to test tritium breeding blanket concepts. These modules are designed to demonstrate the feasibility of producing sufficient tritium in-situ from lithium, a necessary function for any self-sustaining D-T fusion power plant. Source: ITER

Unlike existing fission reactors, the ITER design presents a different safety and waste profile. The fusion reaction itself is not a chain reaction and can be stopped by cutting off the fuel supply or magnetic confinement. The primary radioactive material is tritium, which is handled within a closed loop, and the materials of the vacuum vessel will become activated by neutron flux. However, the long-lived radioactive waste produced is expected to be significantly less than that from fission power plants. The project is not designed to produce electricity; its output is thermal power, which will be dissipated. The focus remains on demonstrating the physics and engineering of a net-gain system. Source: ITER

Successful operation of ITER will provide the essential data for the design of its successor, a demonstration power plant known as DEMO, which will be the first fusion facility to connect to the electrical grid. The construction and assembly of ITER's components, sourced from member nations around the globe, continue to be a major logistical and engineering undertaking. The project's timeline has faced revisions, but progress on major components like the cryostat, vacuum vessel sectors, and magnet systems marks tangible advancement. The operational phase will be critical for validating plasma control models and materials performance under reactor-relevant conditions. Source: ITER