In article ,
David Nebenzahl wrote:

So--and this is completely out of left field, I know--what would happen
if a guy put a vacuum tube--say a biggish octal one, like a 5Y3 or a
6V6--into a microwave and nuked it?

Everything on planet Earth has been put into a microwave. Search YouTube
for "vacuum tube microwave" and you'll get several relevant hits.