Nobody wants a nuclear event to occur, other than those prepper weirdos who secretly need one to happen to justify the small fortune they spent on a fallout shelter. But just in case one does happen, it’s probably smart to keep studying the science of nuclear fallout so we can mitigate as much of the damage as possible.

According to new research from Lawrence Livermore National Laboratory published in the journal Analytical Chemistry and reported by ScienceAlert, scientists have learned quite a bit about what happened inside the radioactive cloud that forms after a nuclear explosion.

And they didn’t even have to set off a nuke to do it.

Instead, the researchers used a plasma flow reactor, a one-meter-long device that can reach temperatures of 5,000 degrees Kelvin. It can recreate some of the extreme conditions found inside a nuclear detonation to observe how all that vaporized radioactive material cools down, condenses, and becomes fallout particles that can linger for decades.

The experiment focused on uranium, cesium, and cerium, with cerium serving as a stand-in for plutonium. Researchers tested two different cooling scenarios. First, temperatures steadily declined, and in the second, temps remained extremely high before rapidly dropping.

The Results Change What We Know About Nuclear Fallout

The results showed that uranium and cerium behaved as expected, condensing relatively early as temperatures fell. Cesium, however, turned out to be a bit of a freak. Instead of condensing, it remained as a vapor for way longer. In a scenario where cooling was delayed, it mixed with other elements and formed more complex chemical compounds than had been anticipated.

Fallout particles keep a record of the conditions under which they were formed. That changes much of what we currently know about how fallout forms, as we once assumed it happens under relatively stable conditions. Turns out, cooling rates can fluctuate, adding a splash of chaos that can make it more difficult to predict what a fallout particle will ultimately look like.  

That’s a valuable lesson to walk away with, since understanding how different materials behave when a nuclear fireball cools down can one day help scientists understand how such a cloud could spread and how the composition of radioactive material inside the cloud can change over time.