In nuclear physics, nuclear fusion is a nuclear reaction in which two or more atomic nuclei collide at very high speed and join to form a new type of atomic nucleus (e.g. The energy that the Sun emits into space is produced by nuclear reactions that happen in its core due to the collision of hydrogen nuclei and the formation of helium nuclei). During this process, matter is not conserved because some of the mass of the fusing nuclei is converted to photons which are released through a cycle that even our sun uses. Fusion is the process that powers active stars.
The fusion of two nuclei with lower masses than iron (which, along with nickel, has the largest binding energy per nucleon) generally releases energy, while the fusion of nuclei heavier than iron absorbs energy. The opposite is true for the reverse process, nuclear fission. This means that fusion generally occurs for lighter elements only, and likewise, that fission normally occurs only for heavier elements. There are extreme astrophysical events that can lead to short periods of fusion with heavier nuclei. This is the process that gives rise to nucleosynthesis, the creation of the heavy elements during events such as supernovae.
A tokamak is a device using a magnetic field to confine a plasma in the shape of a torus. Achieving a stable plasma equilibrium requires magnetic field lines that move around the torus in a helical shape. Such a helical field can be generated by adding a toroidal field (traveling around the torus in circles) and a poloidal field (traveling in circles orthogonal to the toroidal field). In a tokamak, the toroidal field is produced by electromagnets that surround the torus, and the poloidal field is the result of a toroidal electric current that flows inside the plasma. This current is induced inside the plasma with a second set of electromagnets.
The tokamak is one of several types of magnetic confinement devices, and is one of the most-researched candidates for producing controlled thermonuclearfusion power. Magnetic fields are used for confinement since no solid material could withstand the extremely high temperature of the plasma. An alternative to the tokamak is the stellarator.
The ITER fusion reactor itself has been designed to produce 500 megawatts of output power for 50 megawatts of input power, or ten times the amount of energy put in. The machine is expected to demonstrate the principle of producing more energy from the fusion process than is used to initiate it, something that has not yet been achieved with previous fusion reactors. Construction of the facility began in 2007, and the first plasma is expected to be produced in 2020. When ITER becomes operational, it will become the largest magnetic confinement plasma physics experiment in use, surpassing the Joint European Torus. The first commercial demonstration fusion power plant, named DEMO, is proposed to follow on from the ITER project to bring fusion energy to the commercial market.
A power station (also referred to as a generating station, power plant, powerhouse or generating plant) is an industrial facility for the generation of electric power. At the center of nearly all power stations is a generator, a rotating machine that converts mechanical power into electrical power by creating relative motion between a magnetic field and a conductor. The energy source harnessed to turn the generator varies widely. It depends chiefly on which fuels are easily available, cheap enough and on the types of technology that the power company has access to. Most power stations in the world burn fossil fuels such as coal, oil, and natural gas to generate electricity, and some use nuclear power, but there is an increasing use of cleaner renewable sources such as solar, wind, wave and hydroelectric. Central power stations produce AC power, after a brief Battle of Currents in the 19th century demonstrated the advantages of AC distribution.
The world's first power station was built and designed by Sigmund Schuckert in the Bavarian town of Ettal and went into operation in 1878. The station consisted of 24 dynamo electric generators which were driven by a steam engine. It was used to illuminate a grotto in the gardens of Linderhof Palace.
The first public power station was the Edison Electric Light Station, built in London at 57, Holborn Viaduct, which started operation in January 1882. This was an initiative of Thomas Edison that was organized and managed by his partner, Edward Johnson. A Babcock and Wilcox boiler powered a 125 horsepower steam engine that drove a 27 ton generator called Jumbo, after the celebrated elephant. This supplied electricity to premises in the area that could be reached through the culverts of the viaduct without digging up the road, which was the monopoly of the gas companies. The customers included the City Temple and the Old Bailey. Another important customer was the Telegraph Office of the General Post Office, but this could not be reached though the culverts. Johnson arranged for the supply cable to be run overhead, via Holborn Tavern and Newgate.
DEMO (DEMOnstration Power Plant) is a proposed nuclear fusionpower plant that is intended to build upon the expected success of the ITER experimental nuclear fusion reactor. Whereas ITER's goal is to produce 500 megawatts of fusion power for at least 500 seconds, the goal of DEMO will be to produce at least four times that much fusion power on a continual basis. Moreover, while ITER's goal is to produce 10 times as much power as is required for breakeven, DEMO's goal is to produce 25 times as much power. DEMO's 2 to 4 gigawatts of thermal output will be on the scale of a modern electric power plant. Also notably, DEMO is intended to be the first fusion reactor to generate electrical power. Earlier experiments, such as ITER, merely dissipate the thermal power they produce into the atmosphere as steam.
To achieve its goals, DEMO must have linear dimensions about 15% larger than ITER and a plasma density about 30% greater than ITER. As a prototypecommercial fusion reactor DEMO could make fusion energy available by 2033. Subsequent commercial fusion reactors could be built for nearly a quarter of the cost of DEMO if things go according to plan.
The JET facilities are situated on a retired Navy airfield near Culham, Oxfordshire – RNAS Culham (HMS Hornbill), in the UK: the construction of the buildings which house the project was undertaken by Tarmac Construction, starting in 1978 with the Torus Hall being completed in January 1982. Construction of the JET machine itself began immediately after the completion of the Torus Hall, with the first plasma experiments in 1983.
The components for the JET machine came from manufacturers all over Europe, with these components transported to the site.