If we want to convert mass into energy, fission gives the most bang for our buck. Unfortunately that “bang” can be literal. Use of nuclear energy may risk the proliferation of nuclear weaponry, and there’s also the problem of nuclear waste, and the specter of horrible accidents. This last one was painted in terrifying detail in the recent dramatization of the Chernobyl disaster. Nuclear reactors sound scary because the disasters are pretty epic. However the reality is that far, far more people die from straight up air pollution due to coal-fired power plants than ever died in a nuclear reactor accident. In fact the radioactivity around coal-fired plants is also higher due to the trace but completely uncontained radioactive products of coal burning.
But the most compelling attraction is that nuclear power doesn’t directly produce carbon emissions. In fact nuclear power may be our most sure path to reducing carbon emissions and halting climate change. But can we do nuclear power safely enough? There are modern ideas – including the much-hyped thorium reactor – that suggest maybe we can. Before we can understand those we’ll need to review how nuclear reactors work.