i might just point out, and this is a major engineering issue, that the density of metals decreases a lot between a very low temperature (eg -50'C) and a hot day (40-70'C) that it can cause railways to to buckle and become impossible to traverse.

it's not a huge differential, but it's enough to destroy the precision of a machine. a lot of machines made from metal are designed to tolerate this expansion by forming them at a size where they have the optimal tolerances at "working temperature"

"nuclear bombs" suffer from this same problem, but they have much greater intolerance for temperatures causing the uranium/plutonium metal expanding and shrinking, because they require a precise mating of carefully machined surfaces.

this is another aspect of the bullshit factor of the nuclear bomb narrative.

the "gun" style impactor for triggering fission is not so dangerous in the sense that such swelling won't triggen an unintentional meltdown, but it prevents them from detonating (supposedly) properly because they won't mate neatly unless you have a very big and bulky temperature control system around the device.

the imploder style, also suffers from this problem, because not only do the metallic parts shrink and expand with temperature, so do the explosives, and the trigger mechanisms can be affected also by this change of size.