A radiologist today mentioned to me that a great deal of our knowledge about radiation tolerance in medicine (say, in judging appropriate doses or an acceptable number of scans) is derived from atomic bombings or disasters like Chernobyl.
This seems reasonable - we all know of Marie Curie and I imagine that health and safety standards were relatively lax during the first decade or so of bomb tests - but is it correct?
And have we learnt anything else from nuclear explosions/meltdowns 'in the wild' (beyond the obvious things like nuclear safety features)? For example, have physicists learnt anything unexpected from the likes of the 'elephant's foot' at Chernobyl? Or is there absolutely no silver lining to such disasters?
The bombings of Hiroshima and Nagasaki, the inadvertent contamination of the Marshallese with fallout, and accidents like Three Mile Island all present what scientists call "experiments of opportunity." They were not planned experiments, per se, but they did result in opportunities to study a lot of scientifically-interesting phenomena that is otherwise difficult to do (since experimenting with radiation on large populations is unethical).
Basically all of our epidemiological information on the effects of radiation on human beings comes from a handful of these kinds of sources (another was data on uranium miners exposed to radon gas in the American southwest).
There were other scientific discoveries in the wake of things like mushroom clouds. The element Einsteinium was first discovered as a byproduct of thermonuclear blasts.
If you are asking, was anything discovered that totally changed our view of the universe? Not really. But most of science does not do that — it advances very incrementally.
If you wanted to make a somewhat more extended argument, you could look at all of the science that was funded as a result of the nuclear complex. We know a lot about coral atolls because we tested nuclear weapons on them, and the Atomic Energy Commission wanted to know how the weapons affected the ecosystem. We know a lot about the ocean floor and other aspects of oceanography because it is relevant to submarine warfare. We know how to get the Moon in part because because we developed long-range rockets for delivering H-bombs. The Human Genome Project was initiated by the Department of Energy as part of a long-standing funding of genetics research that comes out of the initial question of the impact of radiation on populations. And so on. Is that a "silver lining" or just the flip-side of dual-use research and the military-industrial complex?