Would you prefer to know? Or go off a hunch?
Intuitively, simply not building a bomb seems sufficient to prevent any accidental detonations.
But I'm of course no expert.
The cores of these weapons are unlike any environment on Earth. Maintaining the stockpile without running simulations is negligent.
US ICBM silo map https://qph.fs.quoracdn.net/main-qimg-45b10c7543ed5219a77858...
> okay with nuclear weapons not working when someone wants them to
Obviously s/he hoped the weapons not to explode when fired.
GP wished for a (moderately) likely failure: failure to detonate. GP obviously didn't wish for unlikely failures, like spontaneous detonation, ICBMs all flying to Washington DC, etc.
There is the case of the Goldsboro B52 in 1961 crash in which three bombs could fell out of a plane and could have gone off but didn’t :
https://en.wikipedia.org/wiki/1961_Goldsboro_B-52_crash
Edit: of the four bombs one was only very close to going off, and a lot of lessons were learnt from this event 60 years ago.