NUCLEAR FUSION VS FISSION REACTOR OUTPUT UPGRADE
CCFE’s MAST (Mega Amp Spherical Tokamak) Upgrade is an advanced tokamak experiment trialling a design for compact fusion devices known as spherical tokamaks. It is the focal point of the European fusion research programme which feeds into ITER. These include the Joint European Torus (JET) which is currently the world’s biggest and most powerful tokamak. Among others, this approach is being studied at the US National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, where small capsules of D–T fuel are imploded using pulses of laser light.Ī lot of work is being done at the UK Atomic Energy Agency’s (UKAEA’s) Culham Centre for Fusion Energy (CCFE), where several major projects are underway. Instead, a shock wave compresses it to the immense densities needed. Then there is also inertial confinement, an idea which has also been around since the 1950s where the fusion plasma is not confined by magnetic fields. Now the Wendelstein 7-X experimental stellarator has been built in Greifswald, Germany, by the Max Planck Institute for Plasma Physics (IPP) at a cost of $1.15bn It was completed in 2015.
Initially tokamaks, developed by the USSR in the 1960s were deemed less complex until recently. In the 1950s, US astrophysicist Lyman Spitzer showed that magnetic fields could also be configured in a twisted loop – a device known as a stellarator. However, there are other key fusion methods. The flow of the electrically charged plasma particles themselves also generates a magnetic field that helps to confine the plasma. They use powerful superconducting magnets to hold the plasma in a ring-shaped (toroidal) vessel. Tokamaks are the most common approach to confining the plasma needed for this type of fusion device. Europe is contributing almost half of the costs of its construction, while the other six members to this joint international venture (China, India, Japan, South Korea, Russia and the USA), are contributing equally to the rest. Construction began in 2005 – based on a first-of-a-kind global collaboration. This list relates mainly to fusion produced by a tokamak device, such as that being built by ITER in southern France. Crucially, the average cost per kilowatt hour of electricity is also expected to be similar too fission – slightly more expensive at the beginning, when the technology is new, and less expensive as economies of scale bring the costs down.A Fukushima-type nuclear accident is not possible in a tokamak fusion device. Unlike fission, nuclear fusion reactors produce no high- level activity or long-lived nuclear waste and there are no enriched materials in a fusion reactor that could be exploited to make nuclear weapons.Like fission, fusion does not emit carbon dioxide or other greenhouse gases – its major by-product is helium, an inert, non-toxic gas.Deuterium (D) can be recovered from all forms of water, while tritium (T) may be produced during the fusion reaction as fusion neutrons interact with lithium. Fusion fuels are widely available and are nearly inexhaustible.Per unit mass fusion can release nearly four times as much energy as nuclear fission reactions.“Fusion is a potential source of safe, non-carbon emitting and virtually limitless energy.”.While the fission community tends to support the widely-held belief that fusion “is always 30 years in the future”, the fusion community claims that fusion offers huge advantages compared with fission: Nuclear fission and nuclear fusion have generally followed separate and sometimes competitive paths of development. It’s not all one way either, collaboration may yet prove to be a success for both fields.Ībove: ITER, currently under construction in France, is one of a number of tokomak fusion devices Fusion and fission may be seen as rivals but fusion technologies can learn a lot from their atom-splitting cousins.
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