Having been quietly written off for most of the twenty-first century, nuclear fission is making an improbable return to the centre of debates about (0) DECARBONISATION (CARBON). Advocates argue that no combination of 1RENEW sources alone can reliably supply baseload electricity, and that avoiding nuclear is itself a 2CONTROVERSY position with serious climate implications. Critics counter that the 3DEPLOY timelines of large reactors are routinely underestimated, that proposed 4SAFE have a patchy record in practice, and that long-term 5DISPOSE of spent fuel remains without a fully satisfactory solution anywhere in the world. The risk of weapons 6PROLIFERATE hovers over any expansion of the technology into unstable regions, and continued 7RELY on a small pool of specialist suppliers carries its own geopolitical hazards. Governments now find themselves weighing all of these factors against an inconvenient moral 8AMBIGUOUS: that abandoning nuclear may, in the worst case, lock in fossil fuel dependence for another generation.