That kind of dramatic industrial espionage just isn’t very common outside of fiction. Uranium enrichment really is that difficult due to the precision required

That kind of dramatic industrial espionage just isn’t very common outside of fiction. Uranium enrichment really is that difficult due to the precision required to build gaseous centrifuges and the nasty hydrofluoric acid chemistry involved. ITAR and other restrictions on sale of advanced machinery has much more effect than espionage - the latter is more likely to spread the technology like with Dr Khan and Pakistan/North Korea On top of that, uranium is naturally 99.3% is non-fissile so you need tons of yellowcake to produce a small amount of weapons grade uranium, which requires crazy amount of power for the centrifuges.