Yes, of course: your wannabe WMDer would prefer U-235 all around, given the extraordinary difficulty of achieving near-perfection in the implosion lens fabrication; here, cosmic humor placed a huge barrier between deranged humans and their intent. You just Can't make a gun-type/simple bomb with Pu (though you could squander stolen Pu in an inefficient/dirty--still nasty device.)

I was aware of the inevitable dance twixt the US camps:

A) Let's be ready with some prototypes to test ASAP.. if perchance we might deem it "necessary" to withdraw from the CBT. *cough* *rasp*

B) Let's just play by the rules, use (quite fewer) resources to maintain the aging batches--sans 'new design' attractions and eschewing that expensive What-If? option: which tries to cover all imaginable scenarios, and even 'plans'-in-detail: withdrawal from the treaty, then crash testing programs with candidates already assembled for future test.

(66 years after Hiroshima, this-all is still unalloyed MADNESS, of course--but Muricans must remain #1 in all things having to do with Mine's Bigger: If the designers' penises/vulvas would automatically explode if-their-weapon-ever-did [??] -- how much greater would be the odds for survival of the non-deranged species everywhere, eh?)

I thought this article most useful for its al punte focus upon safety vs reliability aspects of 'defects'. And as we see, most of these alleged or statistically-projected-future? defects which affect Yield: result in only slight degradations in efficiency-of-annihilation. Nine only, of these expected/occasional faults: reach 10% loss. And these are all statistical estimates.

But any 'upgrades to design'--new-design nukes via computer: may compromise [storage/handling/disassembly] safety, even though the Reliability issue, per their own stats, is mostly about accumulating of "1% losses"==rarely beyond 5%.

As there will always be Curtiss LeMay wannabes, obviously the Pentagon as well as all rational people need to be aware of mindsets of A) and of B) factions within these surreal super-classified arguments, upon which none of us can Vote, except highly-peripherally. Were we still Americans, we'd unilaterally disarm down to a handful of these practically-useless things == the only convincing argument possible:
in support of TRUE 'universal nuke disarmament'. That would take guts on all levels. We don't have 'guts' anymore. Pity.

We go either with spending ridiculous levels of $$ to maintain the illusion that we EVER CAN again detonate one of these insane devices
-OR-
We spend ludicrous levels of $$, planning for an actual "war" involving [n+x] 'exchanges' of many many devices.

OK, this was '96: and 15 years later, while many missiles remain damn close to Launch on Warning status: this entire topic is so Off the Radar of all but some miniscule groups: the utter Insanity of the Type-A clan is not an iota less sociopathic than it was in '96.

And THAT is why I'm not sanguine about Sanity breaking-out, especially when now, much of the world is worrying about 'putting food on your family'. Hardly anyone is paying attention to the idea that National Security demands that the US remain capable of launching ~ something like nuclear winter, any old day of the week: with, say, a 98% probability of SUCCESS --OR: we are "underdefended".
Meta-obscenity, that.

Those aged, decrepit or even leaking gadgets were obscene when mass-produced--and will still work well enough to catalyze spasm war with other over-armed entities like the ex-USSR arsenal: Without 'improvements' in 'Reliability' [!!!ONE-1111].
(I read THAT between the lines of the BAS report, don't you?)

We are all screwed by, in A. E's pithy koan: Problems created at one level of thinking … cannot be solved at that same level of thinking.

Nothing there to be sanguine about, I'd say. Hope I'm wrong, that merely 'Luck' stands between utter-madness and survival, so long as the US nuke mindset is mired in '50s paranoia writ large.
Elegant science: Fat Man. Also Infinite Folly, from Day 1, as Bertie woulddid say.