# Could the plume from an exploded nuclear reactor corrode helicopter blades?

I was recently watching the new TV series Chernobyl and was curious if something that occurred was even physically possible. In the show, the physicist instructs the pilots of a helicopter not to fly any closer than 10 meters to the plumes that are being emitted from reactor 4. The pilots disregard the physicist's instructions and fly directly through the plume. Upon emerging on the other side, the blades seem to have corroded to the point that they are slung from the helicopter itself. Is there any way this could physically happen or is it purely cinematic drama?

• Corrosion might be possible if there is some kind of chemical corrosive, such as acids, being produced/vaporized into the plume, perhaps from some ancillary material that is also present in the fire area. But fuel material itself is not a corrosive, I believe (both uranium / plutonium and most of their fission and decay products are typically various elemental metals - e.g. cutting a Uranium [Z = 92] nucleus perfectly in half would give two Palladium [Z = 46] nuclei.). – The_Sympathizer Jun 7 at 1:44
• That said, neutron radiation can produce neutron fatigue which embrittles metal at a molecular level (lattice displacement of metal atoms leading to voids and interstitials which can then act as nucleation sites for crack formation), but that doesn't happen anywhere close to that fast (by the time you got to high enough levels of neutron activity, I'd think it would be instantaneously lethal at the very least, if not outright thermal). – The_Sympathizer Jun 7 at 1:44
• I wouldn't post this as an answer though because I don't know anywhere near enough about all the details of the chemistry of all materials present within a typical nuclear power station around the reactor area. – The_Sympathizer Jun 7 at 1:46
• @The_Sympathizer Note that uranium fission is not symmetric - fission products tend to come out in pairs with masses ~100 and ~130. – Emilio Pisanty Jun 8 at 19:58

This moment is one of the most glaring historical inaccuracies in the series. The helicopter crash happened on October 2, 1986, 5 month after the disaster started, and the reactor fire was already put out by this point. The helicopter crashed because its rotors touched a cable, radiation had nothing to do with it. Here’s an article (in Russian) with detailed discussion and real video of that crash.

Among the helicopters which dropped sandbags into the burning core, none crashed. The series authors moved the event for dramatic effect.

As for radiation, it does not cause significant degradation in metals by itself, at least not this quick. There is a thing called induced radioactivity, which may lead to elements turning into other elements, but usually the fraction of atoms involved is not enough to cause significant mechanical degradation.

The helicopter that flew through the plume and then lost its main rotor blades flew under the bucket cable for a crane that was being used to dump sand on the burning core. the blades struck the cable and sheared off, and the rest of the helicopter fell to the ground and crashed.

• Whether it is what happened in the show or not is irrelevant, the question of whether it could happen or not is still valid and without mentioning that I'm afraid this answer should probably have just been a comment. – RyanfaeScotland Jun 6 at 23:31

Upon emerging on the other side, the blades seem to have corroded to the point that they are slung from the helicopter itself

It seems you've misinterpreted the events as depicted in the clip. There is no corrosion of the blades shown $$-$$ the blades snap off because the helicopter flies into a crane. (As others have mentioned, a helicopter crash of this nature did occur, but not during the firefighting action.)

The implication isn't that the helicopter itself was damaged, but rather that the pilot himself was incapacitated by the radiation (i.e. the prompt gamma radiation from the core shining upwards $$-$$ the same which Legasov warns his helicopter pilot will be deadly when he and Shcherbina arrive to the site), and that this led the pilot to fly into the crane.