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How long is the longest sustained fusion reaction achieved by JET and elsewhere?

Most of the experiments that are carried out in fusion research use only deuterium, rather than a combination of deuterium and tritium (D-T). This is because tritium, as a radioactive gas, is more expensive and has significantly more complicated handling requirements than deuterium. Deuterium-only plasma is sufficient for most of our experiments as it is very similar to D-T plasma. Only two facilities in the world have been set up to use tritium: JET, and TFTR, at Princeton University in the US, which has since been closed down. The next step tokamak (ITER), which is currently build in Cadarache in Southern France, will demonstrate much more powerful fusion reactions for 5-10 minutes and will, hopefully, provide the stepping stone to commercial fusion powerplants.