How long is the longest sustained fusion reaction achieved by JET and elsewhere?
JET is the only operational machine to observe fusion from D-T (Deuterium-Tritium) reactions. Such fusion reactions have been maintained on JET for around five seconds. Experiments in a device called TFTR in Princeton, USA also observed fusion neutrons from their plasma but TFTR is no longer operational. The next step tokamak (ITER), which has been designed and should be built in the next ten years or so, will demonstrate much more powerful fusion reactions for 5-10 minutes and will, hopefully, provide the stepping stone to commercial fusion powerplants.
