[throwaway11460]

Not sure what logic you're imagining. No, it's not based on location of the weapons - it's based on the fact that the top nuclear research institutions of the Soviet Union were in Ukraine.

The space program had a lot of Ukrainians too.

[justsomehnguy]

There is a big leap between "Ukrainian engineers built the nukes" and "some engineers in the Soviet nuclear program were of the Ukrainian ethnicity".

[throwaway11460]

I said Ukrainian engineers built the nukes because that's what happened. Of course they did it as part of the Soviet Union - and yeah, some of the engineers were of the Russian ethnicity too.