However, different isotopes of the same element can have very different nuclear properties. Because different isotopes of the same element have the same number of protons and electrons, they behave similarly in their chemistry (they may behave slightly differently physically due to their different masses). A small amount of hydrogen (about 0.01%) has one proton one neutron, so it is referred to as H-2. For example, the most common isotope of natural hydrogen has just one proton a no neutron, so it is referred to as H-1. They are named using the letter abbreviation of the element and the total number of protons and neutrons in the nucleus. Isotopes are different versions of elements. While the reactor is running, the vast majority of neutrons are produced by the fission of U-235 in our fuel. This chain reaction can continue if there are enough fissile nuclei in a small enough space, and the neutrons don’t get absorbed by other materials or leak out from that space. This process is the fission chain reaction. Those can hit other nearby uranium-235 atoms and cause those to fission, emitting more neutrons. What is a chain reaction?įor example, when a nucleus such as uranium-235 fissions, it emits neutrons. Some isotopes such as californium-252 can spontaneously fission, though most isotopes that are can undergo fission need some stimulation or disruption, such as the absorption of a neutron, in order to cause fission. At the MIT Reactor Lab uranium-235 fissions in the core to produce heat (which we don’t use) and neutrons (which we use for research and experiments). This will prove fusion not only works as an experiment, but works economically on the scale of a power plant.Fission is the nuclear process that involves the splitting of a nucleus. The challenge now is to develop the technology and engineering of tokamaks to capture fusion neutrons and produce electricity. ITER will demonstrate the physics of controlling a power plant-scale fusion plasma. The JET experiments are vital for the next large international experiment, ITER, and will also influence the design work of demonstration fusion powerplants, DEMO and STEP.ĬCFE is part of a worldwide research programme to show that fusion is viable. However, research into reducing these requirements – notably through the use of superconducting magnets – is underway. Today’s tokamaks have high auxiliary power requirements to run the heating systems and energise the magnetic coils. During this experiment, JET averaged a fusion power of around 11 megawatts. JET has produced a record-breaking 59 megajoules of sustained fusion energy over a five second period (the duration of the fusion experiment) using deuterium and tritium – the same fuel mix that will be used in future powerplants. Researchers have overcome many of the scientific hurdles in fusion – developing a good understanding of how to control and confine the hot plasma of fuels. CCFE’s goal is to develop fusion reactors using the tokamak concept. The most advanced device for this is the ‘tokamak’, a Russian word for a ring-shaped magnetic chamber. One way to control the intensely hot plasma is to use powerful magnets. A plasma with millions of these reactions every second can provide a huge amount of energy from very small amounts of fuel. The gas becomes a plasma and the nuclei combine to form a helium nucleus and a neutron, with a tiny fraction of the mass converted into ‘fusion’ energy. To produce energy from fusion here on Earth, a combination of hydrogen gases – deuterium and tritium – are heated to very high temperatures (over 100 million degrees Celsius). This is the opposite of nuclear fission – the reaction that is used in nuclear power stations today – in which energy is released when a nucleus splits apart to form smaller nuclei. When light nuclei fuse to form a heavier nucleus, they release bursts of energy. Fusion is the process that takes place in the heart of stars and provides the power that drives the universe.
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