Alex WellersteinVerified account

I'm not aware of any resolution. The historian Alex @Wellerstein has researched the topic and spoken about it, so he might know more.

It has never shown up in any Soviet archives, and there are no substantiated hints that it did. On the balance I suspect not.

There have been some former spy-types who claim it might have, but former Soviet spies often not reliable on such matters. No real evidence.

Additionally: the general history with Soviet post-Cold War spy stuff was intel agencies claiming credit for nuclear work.

One would imagine that if they could claim to have gotten the USSR the H-bomb — and thus devalue Sakharov's contributions — they would have.

I once asked Edward Teller the extent to which the USSR H-bomb relied on espionage. He insisted it was all Sakharov, not spies.

Sure, but would he know that? He had a definite agenda there. Teller's argument was always that H-bombs were easy for scientists to make.

Hence, in his mind, it was criminal that Oppenheimer et al. had said they shouldn't/couldn't work on them originally.