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Nuclear topic: Nuclear fission and fusion

Fission isa reaction when the nucleus of an atom, having captured a neutron, splits into two or more nuclei, and in so doing, releases a significant amount of energy as well as more neutrons. These neutrons then go on to split more nuclei and a chain reaction takes place.

Nuclear fission is a mature technology that has been in use for more than 50 years. The latest designs for nuclear power plants build on this experience to offer enhanced safety and performance, and are ready for wider deployment over the next few years. There is great potential for new developments in nuclear energy technology to enhance nuclear’s role in a sustainable energy future. Nevertheless, important barriers to a rapid expansion of nuclear energy remain. Governments need to set clear and consistent policies on nuclear to encourage private sector investment. Gaining greater public acceptance will also be key, and this will be helped by early implementation of plans for geological disposal of radioactive waste, as well as continued safe and effective operation of nuclear plants.

The IEA together with the Nuclear Energy Agency have developed a nuclear power roadmap.

Fusion offers important advantages: no carbon emissions, no air pollution, unlimited fuel, and is intrinsically safe. While fusion technology is not at the deployment stage, the potential is substantial. The fusion reaction is about four million times more energetic than a chemical reaction such as the burning of coal, oil or gas.

Fusion is a process where nuclei collide and join together to form a heavier atom, usually deuterium and tritium. When this happens a considerable amount of energy gets released at extremely high temperatures: nearly 150 million degrees Celsius. At extreme temperatures, electrons are separated from nuclei and a gas becomes a plasma—a hot, electrically charged gas.

The fuel (created when deuterium combines with tritium) is abundant; it gives off very little radioactivity; there is no need for underground storage, and there is no environmental risk of high radio-active fuel leakage in case of an accident, the plasma dissipates. Much more work is needed to achieve deployment of fusion technologies.

The IEA Fusion Power Co-ordinating Committee (FPCC) provides a platform for stakeholders to share results of fusion activities worldwide. These stakeholders include the ITER (International Thermonuclear Experimental Reactor) project, the International Atomic Energy Agency, the European Commission (EURATOM), the International Tokamaks Physics Activity (ITPA), and Nuclear Energy Agency (experiments database).

The FPCC also oversees the activities of eight fusion energy technology initiatives (formally known as Implementing Agreements).  These initiatives carry out research and development activities in areas ranging from technology to environmental and economic aspects of fusion power. Their work is directly relevant to the ITER project and the "beyond-ITER" programme, which focuses on fusion power plants, and the economic, environmental, safety and social aspects of fusion power.

As maintaining steady plasma is the greatest challenge for fusion physics research, regardless of the device (toroidal or spherical) or the type of confinement (inertial – using lasers, or magnetic – using electrical current), in 2011 the IEA’s Fusion Power Co-ordinating Committee created a cross-cutting Steady-State Operations Co-ordination Group to ensure no gaps in research worldwide exist.