German Nuclear Program (Bomb/Reactor)

[Nell_Lucifer]

Yet another thread that has German and Nuclear together, which seems to be quite common on this site.
However, this is a bit different than the usual (I hope) as there are some questions I have and not found anything about them on AH (yet).

I will start with the most probable (I guess?) of them.
1. What if they managed to reach criticality in the Haigerloch Cube Reactor? From what I understood, they were only able to get a sub-critical reaction going, needing a few hundred more cubes, which, already existed in Germany.
So, if Heisenberg found out (If he did not already) about the needed cubes, and got them, what would have happened?
I am to believe while the cube configuration is better (in a way) it is more unsafe than rods or plates configuration. Would they be able to stop the reactor if they wanted? How safe was the design etc?
2) What if they managed to get a reactor running in mid 1944? I doubt even if they wanted to turn it into a Plutonium breeder they would have managed to get any Plutonium in the first place. I think there was an allied report where the content of Pu 239 from the German experiments were even lower than usual, their chemical processes eliminating it.
(I am curious about the energy production and allied reaction post war)
3) There is the popular theory on how Germany tested a nuclear weapon in 1945 in the East, under Diebner using a design by Schumann and Trinks in Thuringia. (This was popularized in Hitlers Bombe) As a Fusion-Fission bomb or Dirty Bomb.
When I read about it I was rather skeptical as you can guess, finding the idea absurd... However, such a design, would lower the required amount of enriched uranium/plutonium to start very fast critical chain reaction.
Then, I found this. https://www.degruyter.com/document/doi/10.1515/zna-2004-0603/html
So how viable would have been for Germany to make such a fission-fusion-fission bomb? Instead of the American Uranium gun or Plutonium implosion?

4) If they managed to get a Fusion-Fission or Fission-Fusion-Fission bomb in early 1945 (Feb), with another one (May) where would they use it? Moscow? And would the existence of such a weapon make the Allies reconsider a conditional surrender?

 

[Garrison]

There is just no chance of building a German A-Bomb. Look how long it took the Allies, who had massive amounts of available resources and a secure place to work free from the threat of enemy attack, Newt Gingrich's 1945 notwithstanding. And that popular theory on the Germans testing a nuclear weapon is right up there in terms of credibility with Nazi flying saucers and secret Antarctic bases.

 

[Post]

4) If they managed to get a Fusion-Fission or Fission-Fusion-Fission bomb in early 1945 (Feb), with another one (May) where would they use it? Moscow?

Nowhere, because they don't have a delivery system.
Unless of course the Post Office's program makes the bomb, they could mail it to Roosevelt, Churchill and Stalin.
"Hey, we've got a package for you, please sign here...Yes, I know it's large, but don't worry, it will self destruct."

 

[Nell_Lucifer]

There is just no chance of building a German A-Bomb. Look how long it took the Allies, who had massive amounts of available resources and a secure place to work free from the threat of enemy attack, Newt Gingrich's 1945 notwithstanding. And that popular theory on the Germans testing a nuclear weapon is right up there in terms of credibility with Nazi flying saucers and secret Antarctic bases.

Let's discuss the bomb part of this then. I agree that the existence of a nuclear bomb test is highly unlikely even if they were working on such a design.
But regarding no chance of building a nuclear bomb? I disagree.
The allies pursued 3 different avenues, uranium gun, plutonium gun and implosion of plutonium. While there were other designs that were either dead ends or scrapped for their complexity. In addition, they tried different methods of obtaining HEU and Pu. Gaseous diffusion, thermal diffusion, etc.
I've seen on older threads that it costed about 2 Billion dollars, as expensive as the V-2 Program (And even if some estimates place it a 30% of that) The Germans could pursued one design instead of the 3 the Allies did at about the same cost (Without giving up on it in 1942).

But while this is about the path(s) the Allies took, it wasn't the only one.
I was not asking about a Plutonium implosion or Uranium gun type, I was asking about a fusion-fission or fission-fusion-fission type.
Which would require less mass for the Uranium and even less for the Plutonium depending what they pursue.

Nowhere, because they don't have a delivery system.
Unless of course the Post Office's program makes the bomb, they could mail it to Roosevelt, Churchill and Stalin.
"Hey, we've got a package for you, please sign here...Yes, I know it's large, but don't worry, it will self destruct."

I am pretty sure the Me 264, He 177 (There was a modified version with a larger bomb bay, I think V31 in Prague) or even Ju 390 could do the job. (Fat Man was around 5000 kgs, I imagine German bomb would not weigh more than 6 tons...)

 

[marathag]

What if they managed to reach criticality in the Haigerloch Cube Reactor

It would then do a runaway reaction,followed by meltdown
Germans didn't think control rods were needed for their reactor design
Whoops!

 

[Garrison]

Let's discuss the bomb part of this then. I agree that the existence of a nuclear bomb test is highly unlikely even if they were working on such a design.
But regarding no chance of building a nuclear bomb? I disagree.
The allies pursued 3 different avenues, uranium gun, plutonium gun and implosion of plutonium. While there were other designs that were either dead ends or scrapped for their complexity. In addition, they tried different methods of obtaining HEU and Pu. Gaseous diffusion, thermal diffusion, etc.
I've seen on older threads that it costed about 2 Billion dollars, as expensive as the V-2 Program (And even if some estimates place it a 30% of that) The Germans could pursued one design instead of the 3 the Allies did at about the same cost (Without giving up on it in 1942).

But while this is about the path(s) the Allies took, it wasn't the only one.
I was not asking about a Plutonium implosion or Uranium gun type, I was asking about a fusion-fission or fission-fusion-fission type.
Which would require less mass for the Uranium and even less for the Plutonium depending what they pursue.


I am pretty sure the Me 264, He 177 (There was a modified version with a larger bomb bay, I think V31 in Prague) or even Ju 390 could do the job. (Fat Man was around 5000 kgs, I imagine German bomb would not weigh more than 6 tons...)

Again the stories about a nuclear test are nonsense peddled by the same sort of documentary makers who produce UFO and Bigfoot shows for Discovery Channel. The Allies could afford to pursue all options, the Germans could not. The Nazis specifically halted A-Bomb research because they realized it would take 3-4 years to build one, if it was possible at all, something that was far from certain in 1941. The Germans knew that if the war dragged on that long they were doomed.

The Allies flattened Peenemunde to disrupt German rocket research, they sank a ferry full of civilians to deny the Germans a supply of heavy water, they were willing to assassinate physicists to stop them helping the Germans build a nuclear weapon, what do you think they will do when they find out about this project?

Leave that aside, lets suppose the Nazis get a dirty bomb and use it, why in the world would that make the Allies more likely to let Nazi Germany survive? So they can build a full working A-Bomb so London or Moscow disappears in a mushroom cloud? But please do expand on what outcome you expect/want from such a development.

 

[Post]

I am pretty sure the Me 264, He 177 (There was a modified version with a larger bomb bay, I think V31 in Prague) or even Ju 390 could do the job. (Fat Man was around 5000 kgs, I imagine German bomb would not weigh more than 6 tons...)

ME-264: only three prototypes were build, cancelled in 1944
Ju-390: never flew (the alleged flights it is supposed to have made are very much in doubt)
HE-177: Might work, if the bombbay is big enough. Looking up the V-38, if found several discussions about the exact reason why it was fitted with an enlarged bombbay and if it would be big enough.

Apart from that, the allies had airsupremacy. To get the plane to the target is a big gamble.

 

[juanml82]

A suicide submarine crew may have been able to plant the bomb into the harbor, or nearby, a coastal city. Or maybe leave a timed device, which may or may not work, near the shore and leave. It's not as efficient as using a bomber, but it may give Germany a better chance.
Then again, the Allies also had naval supremacy, so I'm not sure about the chances a submarine would have to infiltrate, let's say, Antwerp by 1944

 

[gatordad699]

Did you read the paper you cited?
“I had first used the term “mini-nuke” in an unpub-lished report following my 1973 paper in Nature [1],but this terminology should not be confused with therecent use of this same word for small nuclear explo-sive devices intended for military applications.” Reading through the paper, the author is talking about small enough fission events that they are captured for their energy release. He is also discussing how to start fusion using small fission events. This is all theory stuff that would be hard to manufacture today. Much less 1944. He discusses using lasers and particle streams to start events. Pretty sure 1944 Nazi Germans didn’t have those laying around.
As for their cube reactor. IMHO they knew less than nothing about reactor design. As another poster said, no control rods. How were they going to control neutrons to control the reaction rate? What was the coolant flow path to remove heat? Reflectors? How would they perform an emergency shutdown? Looking at pictures of it, just looks like cubes hanging in coolant. Do not see any way to having it work.

 

[Garrison]

A suicide submarine crew may have been able to plant the bomb into the harbor, or nearby, a coastal city. Or maybe leave a timed device, which may or may not work, near the shore and leave. It's not as efficient as using a bomber, but it may give Germany a better chance.
Then again, the Allies also had naval supremacy, so I'm not sure about the chances a submarine would have to infiltrate, let's say, Antwerp by 1944

Not an impossible scenario if they had a dirty bomb, but I suspect the most it would achieve would be to get the Allies to double down on destroying Nazi Germany ASAP.

 

[marathag]

How would they perform an emergency shutdown

toss in chunks of Cadmium and hope

 

[Nell_Lucifer]

It would then do a runaway reaction,followed by meltdown
Germans didn't think control rods were needed for their reactor design
Whoops!

How bad would it have been? I believe there were around 640+ cubes in the original configuration, needing 1000 in total to reach criticality, a cube containing (I am not sure) 2.5 Kgs of Uranium, so about 2500 Kgs of Uranium for the Reactor to work. How bad would the meltdown be? And, would the radiation kill all the nearby physicists?
(As a note, here, http://www.safetyinengineering.com/...esearch in Germany 1938-1945_1372331935_2.pdf , I arrived at this mention for the reactor.

So, if it did have Cadmium control rods, would there be no safety hazards? )

Again the stories about a nuclear test are nonsense peddled by the same sort of documentary makers who produce UFO and Bigfoot shows for Discovery Channel. The Allies could afford to pursue all options, the Germans could not. The Nazis specifically halted A-Bomb research because they realized it would take 3-4 years to build one, if it was possible at all, something that was far from certain in 1941. The Germans knew that if the war dragged on that long they were doomed.

Agree, there were tests made on these supposed locations with no proof that there was indeed a nuclear test.
Yes, that was what I said. For the Germans to obtain a nuclear bomb would be impossible by following the path the Allies took. (And the mistakes they made, the uranium mass needed - while different people had different numbers, they were high, or identifying graphite as being unsuited as a moderator)

The Allies flattened Peenemunde to disrupt German rocket research, they sank a ferry full of civilians to deny the Germans a supply of heavy water, they were willing to assassinate physicists to stop them helping the Germans build a nuclear weapon, what do you think they will do when they find out about this project?

Peenemunde was housing bunkers, research facilities, apartments, where thousands of people worked, and where spies managed to find themselves inside. Compared to the Nuclear Club of at most 120 people at its peak.
However, I am dubious of the Allied intel on the Nuclear Program, they only found out about the missing Thorium from France when they captured Paris (Which, I think eventually lead them to Haigerloch's Atomkeller)
This is an extract of the Farm Hall discussion of German physicists.
>>HARTECK: One would have had to have a complete staff and we had insufficient means. One would have had to produce hundreds of organic components of uranium, had them systematically examined by laboratory assistants and then had them chemically investigated. There was no one there to do it. But we were quite clear in our minds as to how it should be done. That would have meant employing a hundred people and that was impossible.
(...)
HARTECK: If it is a fact that an explosive can be produced either by means of the mass spectrograph we would never have done it as we could never have employed 56,000 workmen. For instance, when we considered the CLUSIUS – LINDE business combined with our exchange cycle we would have needed to employ 50 workmen continuously in order to produce two tons a year. If we wanted to make ten tons we would have had to employ 250 men. We couldn't do that.
WEIZSÄCKER: How many people were working on V 1 and V 2?
DIEBNER: Thousands worked on that.
HEISENBERG: We wouldn't have had the moral courage to recommend to the Government in the spring of 1942 that they should employ 120,000 men just for building the thing up.<<

Leave that aside, lets suppose the Nazis get a dirty bomb and use it, why in the world would that make the Allies more likely to let Nazi Germany survive? So they can build a full working A-Bomb so London or Moscow disappears in a mushroom cloud? But please do expand on what outcome you expect/want from such a development.

I never suggested that. I said conditional surrendering. The Allies could at least stomach a 'non' Nazi Government (Churchill especially, given his dislike of Stalin and Communism, and the 'Fourth Fuhrer' Donitz's Government that was left to life for a few more weeks.)
Anything is better than unconditional surrendering.
Also, Bombing Moscow would cut off the whole Soviet Government, no more Stalin or his clique, no supply hub (not likely that would stop the Red Army after the bombing for a few weeks) but it might spare Europe some of the Cold War (as was in OTL), perhaps a smaller Iron Curtain?
Even if the unconditional surrender remains, Hitler would happily commit suicide thinking that he took Stalin with him.

ME-264: only three prototypes were build, cancelled in 1944
Ju-390: never flew (the alleged flights it is supposed to have made are very much in doubt)
HE-177: Might work, if the bombbay is big enough. Looking up the V-38, if found several discussions about the exact reason why it was fitted with an enlarged bombbay and if it would be big enough.

Apart from that, the allies had airsupremacy. To get the plane to the target is a big gamble.

I am aware, but, I think there would be a different choice made if they were working on a nuclear bomb and were expecting one in 1945. But even so, having 1 weapon and a few prototypes around doesn't sound like a problem. They only need 1 plane to deliver the bomb, if it works they can build more.
I think the Soviets were less prepared at that point compared to the West. And I don't believe they would expect one lone strike on Moscow.

Did you read the paper you cited?
“I had first used the term “mini-nuke” in an unpub-lished report following my 1973 paper in Nature [1],but this terminology should not be confused with therecent use of this same word for small nuclear explo-sive devices intended for military applications.” Reading through the paper, the author is talking about small enough fission events that they are captured for their energy release. He is also discussing how to start fusion using small fission events. This is all theory stuff that would be hard to manufacture today. Much less 1944. He discusses using lasers and particle streams to start events. Pretty sure 1944 Nazi Germans didn’t have those laying around.
As for their cube reactor. IMHO they knew less than nothing about reactor design. As another poster said, no control rods. How were they going to control neutrons to control the reaction rate? What was the coolant flow path to remove heat? Reflectors? How would they perform an emergency shutdown? Looking at pictures of it, just looks like cubes hanging in coolant. Do not see any way to having it work.

Yes, I did read it, while true, lasers were not an option, the paper starts initially with chemical explosions to start the reaction. I just wanted to point out that it would be somewhat more feasible for the Germans to go with Boosted/Fusion-Fission or, as shown in the paper, Fission-Fusion-Fission to decrease the necessary mass needed to reach criticality. (After all, they thought about using Deuterium for a nuclear weapon)
"just looks like cubes hanging in coolant."

They were hoping to use the coolant as a starter for criticality.
At least they managed to produce in a gas centrifuge 2.5 mgs of enriched Uranium (No idea if the total, or at an interval, the centrifuge got blown up in 1944)

 

[Garrison]

Peenemunde was housing bunkers, research facilities, apartments, where thousands of people worked, and where spies managed to find themselves inside. Compared to the Nuclear Club of at most 120 people at its peak.

You can't use the OTL 'never actually a serious program' numbers, do you honestly think they could come up with a working device with 120 people?

The Allies could at least stomach a 'non' Nazi Government (Churchill especially, given his dislike of Stalin and Communism, and the 'Fourth Fuhrer' Donitz's Government that was left to life for a few more weeks.)

So you don't think Doenitz was a Nazi and that the Allies would tolerate him and the other surviving Nazi Generals running Germany?

Anything is better than unconditional surrendering.

Please illuminate in what way is this is 'better'?

 

[Nell_Lucifer]

You can't use the OTL 'never actually a serious program' numbers, do you honestly think they could come up with a working device with 120 people?

Hmm, yes you are right. But I don't think the program (if serious, and how serious) would look like the American one. They would try to disperse it as much as they can, building centrifuges in underground workshops (Like with the V-2) or spread around so they are hidden from Allied bombers (Not like the bombs had much precision to begin with)
And I assume people in this project would be from the beginning higher on the security check, compared to the V-2 Program.

So you don't think Doenitz was a Nazi and that the Allies would tolerate him and the other surviving Nazi Generals running Germany?

No, not really, pretty much everyone was a Nazi and some even reached high ranking positions post-war.
It's not like the Allies had problems employing Nazis that were much worse than Donitz (Who, I believe was accused of Unrestricted Submarine Warfare, even if the Americans were also doing it)
And if they really have trouble with Donitz leading the new German Government, they can push to have someone they stomach or perhaps consider alright.

Please illuminate in what way is this is 'better'?

I think it is obvious, obtaining/having any guarantee that they will not be at the complete mercy of the Allies after they surrender, fearing they would become slaves or having Germany broke apart.
Even letting them to have any industry or army whatever minuscule would be more preferable. (Eg Versailles)
When FDR announced the Unconditional Surrender in 1943, Churchill was surprised and even annoyed as he was not informed of that, and with Truman in charge there might be possible to have some sort of accord between a New German Government.

 

[Garrison]

I think it is obvious, obtaining/having any guarantee that they will not be at the complete mercy of the Allies after they surrender, fearing they would become slaves or having Germany broke apart.
Even letting them to have any industry or army whatever minuscule would be more preferable. (Eg Versailles)

So a surviving Nazi regime is better in your opinion?

 

[David Flin]

At least they managed to produce in a gas centrifuge 2.5 mgs of enriched Uranium (No idea if the total, or at an interval, the centrifuge got blown up in 1944)

How enriched? The percentage enrichment needed for a reaction, such as you might get in a nuclear reactor, is typically around 35%. The percentage enrichment required for use in a nuclear bomb is much higher, around 80%.

(Apologies if my numbers are a little off, I am on a phone and away from my references).

Saying "enriched uranium" is completely meaningless if we don't know how enriched.

For the record, enriching becomes harder as you increase enrichment levels. As a very rough rule of thumb, increasing enrichment by 10% is four times as hard as the previous 10%.

 

[Nell_Lucifer]

So a surviving Nazi regime is better in your opinion?

I did not say that. Ofc it won't be a Nazi regime, everyone would the OTL "I was not actually a Nazi" and (We are certainly going to distance ourselves as far as possible to Nazism to not give the Allies any idea of finishing the job)
And I find better having a de-nazifing German Government than Eastern Europe full communist.

How enriched? The percentage enrichment needed for a reaction, such as you might get in a nuclear reactor, is typically around 35%. The percentage enrichment required for use in a nuclear bomb is much higher, around 80%.

(Apologies if my numbers are a little off, I am on a phone and away from my references).

Saying "enriched uranium" is completely meaningless if we don't know how enriched.

For the record, enriching becomes harder as you increase enrichment levels. As a very rough rule of thumb, increasing enrichment by 10% is four times as hard as the previous 10%.

Unfortunately I could not find (yet) what enrichment they managed, there is surprisingly little on the subject. (I would say 80% because I.G Ferben? I don't remember the name of the company, experimented with 5% enrichment, they also had enriched Uranium to play in their 1942 L-VI Leipzig pile that blew up.

 

[Garrison]

I did not say that. Ofc it won't be a Nazi regime, everyone would the OTL "I was not actually a Nazi" and (We are certainly going to distance ourselves as far as possible to Nazism to not give the Allies any idea of finishing the job)
And I find better having a de-nazifing German Government than Eastern Europe full communist..

How exactly will it be denazified when you are proposing leaving a Nazi in charge? And why is leaving people asscociated with mass murder and slave labour in charge better than going Communist?

 

[David Flin]

I did not say that. Ofc it won't be a Nazi regime, everyone would the OTL "I was not actually a Nazi" and (We are certainly going to distance ourselves as far as possible to Nazism to not give the Allies any idea of finishing the job)
And I find better having a de-nazifing German Government than Eastern Europe full communist.

Unfortunately I could not find (yet) what enrichment they managed, there is surprisingly little on the subject. (I would say 80% because I.G Ferben? I don't remember the name of the company, experimented with 5% enrichment, they also had enriched Uranium to play in their 1942 L-VI Leipzig pile that blew up.

5% enrichment is pathetic. It's barely enough to do experiments on. There are rocks in Canada with higher levels of enrichment than that.

Without knowing if you're talking about uranium enriched to 35% - usable in reactors to generate a sustainable reaction- or uranium enriched to 80% (and again,my caveat on the precise number applies), we don't know if the 2.5mg you mention is pathetically inadequate or completely and utterly pathetically inadequate. IIRC, critical mass of 80% enriched uranium is around 5kg. (Caveat applies).

Any source that doesn't quote the percentage enrichment is basically worthless with regard to discussions on this subject.

 

[Nell_Lucifer]

How exactly will it be denazified when you are proposing leaving a Nazi in charge? And why is leaving people asscociated with mass murder and slave labour in charge better than going Communist?

Like it happened in OTL...
>From 1949 to 1973, 90 of the 170 leading lawyers and judges in the then-West German Justice Ministry had been members of the Nazi Party.
>In 1957, 77% of the ministry's senior officials were former Nazis.
>between 1949 and 1970, 54% of Interior Ministry staffers were former Nazi Party members, and that 8% of them had served in the Nazi Interior Ministry.
Because now they could no longer kill people while the communist governments could. (Allied presence and democratization)