I recently stumbled on a strange conspiracy about a German military base at Ohrdruf during WW2, which mixes hearsay with lack of evidence (missing documents), abnormally lengthy classification periods for captured documents, and ties it into a longer narrative alleging the development of non-fission nuclear weapons. Possibly what we today would call "dirty bombs".
Would any experts here be so kind as to take a look and provide their take on the evidence provided? I'm interested in whether any of the evidence might have a more plausible and innocent interpretation and whether the author of this forum post is just cherry picking or outright making things up.
One can rule out German non-fission nuclear weapons on three points:
The Germans never developed working nuclear reactors and thus could not have developed nuclear fission products in quantity. You need working reactors to make the by-products that would be needed for radiological warfare in the quantities necessary.
The other method that is sometimes proposed that they researched, that they would use high-explosives to induce fusion reactions, doesn't work. (We've tried it. If it did work, it would be awesomely useful for many different things. It doesn't work. Fusion is much harder than that and requires compression pressures orders of magnitude higher than high explosives can provide.)
We know #1 definitively because the Allies spent a lot of time dissecting the German program. We have very detailed records of what both of the "uranium club" teams were working on. They did not develop working reactors (the closest they got was a reactor with a ~0.8 neutron replacement rate, which is subcritical) and those were just small test reactors (not the industrial-sized ones you'd need to actually breed fission products or fissile material). So we actually have a lot of evidence about their programs — evidence from multiple people, multiple sites, etc. So there is also a burden on whomever would assert the contrary to explain away.
I would also note that the forum has provided no evidence. They've provided assertions. That is not evidence. But as to the suggestion that these were some kind of catalyzed high explosive or some kind of fuel-air mixture — that is not implausible from a technical standpoint, and both the Allies and Axis powers explored this kind of thing during the war. The notion that these kinds of chemical explosives could be as deadly or large as an atomic bomb is false, though. Fuel-air bombs are impressively large but still orders of magnitude less explosive and less efficient than atomic bombs. The largest fuel-air bombs developed by the USA and Russia (the MOAB and the FOAB) yield between 10-40 tons of TNT. Those are big bombs, and we did make some very, very tiny tactical nuclear weapons in that yield range as well (the itty-bitty Mk-54 could go as low as 20 tons or so). But the Hiroshima bomb was 15,000 tons of TNT equivalent – over two orders of magnitude more powerful. It's just not comparable.
The rest of the stuff is a mix of cherry-picking, speculation, and total bonkers. The Germans did ship some uranium to Japan. The Japanese wanted to use it as a catalyst. The idea that this is in any way connected to the US bombing of Japan, or that the Japanese could do anything interesting with that in the short term, is completely silly from a technical perspective. And then the forum derails into standard "the Germans were maybe close to an atomic bomb" nonsense.