Dr Gilles Arnoux and Tom Farley visited Chigwell. Both work at the CCFE – the Culham Centre for Fusion Energy, in Oxfordshire. Dr Arnoux explained the differences between nuclear fission (how ‘ordinary’ nuclear reactors work, by splitting atoms) and nuclear fusion (how stars like the sun produce energy, by fusing two hydrogen atoms into one helium atom). Nuclear fusion has huge potential, as the fuel is almost limitless (sea water), the waste products are much safer, and there is no risk of a Fukushima-style meltdown. We learnt in detail how the Culham reactor was designed and built, with a complex system of magnets to keep the incredibly hot plasma away from the sides, and how a much bigger reactor is being built in France. His talks were followed by very interesting question-and-answer sessions.