Just a thought--if 'the universe is expanding' (red shift/dark energy), that is identical to 'everything in the universe is shrinking'.

'Everything' including the size of every atom, bringing Uranium atoms closer together, causing more chain reactions, lowering critical mass. In a billion years every nuke might spontaneously detonate.

Inspect your Uranium. I'd bet the half-life has changed since originally measured 90 years ago.