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According to "neutrons make other things radioactive", anything that carry by that fission 747 "might" be radioactive after a flight.

True?



From what I've read at just the level of Wikipedia, I'd guess yes. But nuclear physics just is not my field.

I wanted my Ph.D. in mathematical physics, but all the physics courses I could find did the math in very sloppy ways, and my hope for any research progress in physics wanted to do the math with full care. I did get much of that math, but by then I was occupied with my money making work and didn't get back to physics. I'd like to, maybe, someday! Then maybe I'll be able to give you a solid answer.

For now, some of the discussions claim that a lot of neutrons will make a metal brittle but don't go the next step and explain just why. Before I'd say anything about what neutrons do, if only as a check on the level of understanding, I'd want to know why.


This seems to explain much of it:

http://en.wikipedia.org/wiki/Wigner_effect

Whatever production process partially relies on arranging the crystal structure of the metal to arrive at desirable properties, the neutrons disrupt it.


Okay, I'll accept that: What used to be the usual isotopes of iron, carbon, aluminum, etc. with some extra neutrons, after whatever gamma rays, alpha particles, etc. boil off, becomes some other isotope or element that doesn't fit in the crystal and, thus, makes the crystal brittle.


It can happen without neutron absorption, the neutrons simply knock the atoms out of alignment, and they bounce around a bit (so each neutron can cause more than 1 defect).

(if it doesn't follow why that would matter, look into the heat treatment of steel)




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