Nuclear fusion will never be a practical source of electrical power, argues a prominent scientist in the journal Science.

Even nuclear fusion's staunchest advocates admit a power-producing fusion plant is still decades away at best, despite forty years of hard work and well over $20 billion spent on the research. But the new paper, personally backed by the journal's editor, issues a strong challenge to the entire fusion programme, arguing that the whole massive endeavour is never likely to lead to anything practical or useful.

The issues include the potentially prohibitive costs of building, and the difficulties of repairing and maintaining the reaction vessel. This massive "blanket" of lithium and rare metals - that must surround the fusion-generating plasma in order to absorb its emitted neutrons - will degrade and become radioactive over time, requiring regular dismantling and replacement