OK kids, it's time for a science lesson. This is Culham Centre for Fusion Energy near Oxford in England. It houses two of the world's foremost experiments into nuclear fusion energy, the Joint European Torus (JET) experiment and the Mega Ampere Spherical Tokamak (MAST) experiment.
Lets kick off with some basics - and in my classically-trained-highly-edjumucated-scientific-maximimum-journalistic-integrity-styleeee I am basically just going to paraphrase this article about how this all works. Nuclear fusion (notice the u in fusion) reactors are thought to be one of the biggest hopes for the future of energy - they will use abundant sources of fuel (deuterium, which can be extracted from seawater), produce a minimal amount of waste and be less dangerous than current nuclear rectors which use nuclear fission (notice the i in fission). Nuclear fission creates energy by splitting one atom into two atoms, and at the same time as creating massive amounts of energy, creates radiation and radioactive waste that lasts a long, long time. Nuclear fusion on the other hand, creates energy by joining two atoms to one: two hydrogen atoms come together to form helium atoms, neutrons and a hell of a lot of energy. It's the same kind of reaction that happens in the sun.
Conceptually, harnessing the power of nuclear fusion has been easy-peasy, but in practice scientists have found it extremely difficult to contain and control the reaction. For starters, fusion requires a temperature of about 100 million kelvin, which just happens to be six times hotter than the core of the sun. It also needs extremely high pressure (the atoms need to be squeezed really close to each other) - and the sun can do this because of its huge mass and force of gravity. We need to use intense magnetic fields or powerful lasers to achieve this, and the most efficient shape for the plasma to be squeezed into is a kind of donut shape called a tokamak - which is what JET uses.
The JET experiment, the largest facility of its kind in operation, was commissioned by the Council of the European Community in 1973 and opened by the Queen in 1984. In 1991, the world's first controlled release of fusion energy was achieved, and in 1997 JET produced 16 megawatts of fusion power, a world record. At the moment JET is working towards handing over research in this field to the International Thermonuclear Experimental Reactor (ITER), a huge experiment being constructed in Cadarache in the south of France. The ITER project aims to make the long-awaited transition from experimental studies of plasma physics to full-scale electricity-producing fusion power plants, and is funded by the EU, India, Japan, China, Russia, South Korea and the United States. ITER is designed to produced 500 megawatts of power, and is intended to be the stepping stone between purely experimental fusion physics and applying the practices to commercial use. It will begin experiments in 2020.
The MAST experiment is a smaller experiment that is designed to test different principles related to fusion energy, specifically the shape of the tokamak.