I was thinking maybe the radiation generates heat - but from the following post found on Reddit it is more just the energy it sounds like. Obviously I don’t know anything, but what the random poster stated sounds like it makes sense:
“Strong radiation does a number on electronics. The particles have enough energy that if they impact molecules in a semiconductor, they ionize the material (liberate electrons from their parent atoms). This can cause a variety of effects.
At low levels, it causes “soft errors”. The sudden liberation of charged particles causes circuits to misbehave and interpret what should be a digital “0” as a “1” (or vice versa). This can cause temporary misbehavior, or flip bits in memory.
At more extreme levels, it can damage thin insulators (and their interfaces with the semiconductor) and cause permanent paths of electrical “leakage” (current flows where it shouldn’t). These “hard errors” can render circuits inoperative.
It is somewhat possible to mitigate these issues, but if the radiation is really strong, it’s almost impossible to do with something small like a robot. They simply can’t carry the amount of shielding that would be required.
At really, really strong radiation levels, the bonds in metals can be damaged, causing the metal to become brittle and weaker than it should be.”
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By the way, the article keeps talking about the effects on humans with these huge numbers below the containment floor or what have you. Pretty meaningless, seeing as no human is ever going to go in there!
Several decades ago there was a problem detected with higher density ram chips. Apparently there were trace amounts of radioactive materials in the packaging of the integrated circuits and the emissions were sufficient to cause soft errors in the memory.
I do recall that there was a time when some thought that we might have reached some practical limit to memory densities. We know now that the limit is still some way off a quarter of a century later.