Nuclear fusion ‘holy grail’ is not the answer to our energy prayers | Letters

Dr Mark Diesendorf questions the claim that nuclear fusion is safe and clean, while Dr Chris Cragg suspects true fusion power is a long way off. Plus letters from Dick Willis and Martin O'Donovan

You report on the alleged breakthrough" on nuclear fusion, in which US researchers claim that break-even has been achieved (Breakthrough in nuclear fusion could mean near-limitless energy', 12 December). To go from break-even, where energy output is greater than total energy input, to a commercial nuclear fusion reactor could take at least 25 years. By then, the whole world could be powered by safe and clean renewable energy, primarily solar and wind.

The claim by the researchers that nuclear fusion is safe and clean is incorrect. Laser fusion, particularly as a component of a fission-fusion hybrid reactor, can produce neutrons that can be used to produce the nuclear explosives plutonium-239, uranium-235 and uranium-233. It could also produce tritium, a form of heavy hydrogen, which is used to boost the explosive power of a fission explosion, making fission bombs smaller and hence more suitable for use in missile warheads. This information is available in open research literature.