Nuclear Energy

A lot of energy from little fuel, and obligations that last for generations.

A chain small in mass and long in responsibility

Nuclear fission starts from a principle unlike any other source in this section: instead of burning carbon, it splits heavy uranium nuclei and releases the energy that held that nucleus together. That mechanism means a tiny mass of fuel — on the order of grams, not tonnes — can keep a city lit for months, a density no chemical or renewable source can match. That same density, however, is why the chain surrounding the reactor is so long and so closely watched: uranium has to be mined and concentrated, converted and enriched in specialized industrial facilities, the reactor has to operate under an exceptionally strict safety regime, and finally the used fuel has to be guarded for centuries after it has stopped being useful, since it remains radioactive long after.

Four questions that only make sense answered together

This section follows four threads that are usually presented in isolation in public debate, but only make sense read together: where the fuel comes from and what preparing it costs (the fuel cycle), how much electricity it produces and at what real financial cost (fission), what can go wrong and how it is prevented (safety), and what remains once the fuel is no longer useful (waste). Talking only about the carbon-free electricity coming out of the reactor, without mentioning the mine or the waste, is as incomplete as talking only about the worst possible accident without mentioning the continuous, carbon-free production the technology has sustained across most of its seven decades of civilian history.

The economic argument is the hardest to summarize in one sentence

Unlike safety — where the complete historical balance has a reasonably clear answer, see this section's safety page — the cost of nuclear energy has no universal figure: an already-amortized plant still operating, an expansion of an already-built design, and a first-of-a-kind reactor of a new technology are, in practice, three completely different financial ventures, with very different risks of cost overrun and delay. That variability — not reactor physics — is what explains why countries using nearly identical reactors end up with such different final costs.