How far Nazis were in their nuclear program?

“Werner Heisenberg, a theoretical physics leader of the project; Paul Harteck, an experimental leader. Walter Bothe, a leader on the project's cyclotrons; uranium processing in Katanga, Belgian Congo; Vemork, the project's source of heavy waterLeipzig L-IV, an early nuclear experiment; also, mission soldiers dismantled the Haigerloch atomic pile” (Wikipedia, German nuclear program during World War II)

Germans had a nuclear reactor known as B8. Today, people say. Heisenberg underestimated. The mass of fissile material needed. But natural uranium is not enough.  Fissile material should have a high enough enrichment level. And. Its purity should be high enough. Those things are required for a self-sustaining nuclear reactor. I think that the Manhattan Project used pre-enriched uranium in its reactors. Germans used natural uranium. Without a prior enrichment process.  In that process. Raw uranium is separated from other ore. Then that raw uranium is combined into a liquid, as uranium hexafluoride. will be driven into another centrifugal system. The system must separate U-235 from U-238.  Nuclear-weapon plutonium is made by bombarding U-238 with neutrons.

We don’t know. If. Heisenberg knew about the enrichment levels and heavy water levels in April 1945.  When. He tried to start the reactor core. That attempt failed. There is a possibility that he was afraid that the Gestapo would shoot him. 

“In the spring of 1945, with Nazi Germany collapsing around them, German physicists lowered hundreds of small uranium cubes into a tank of heavy water inside a rock cellar in the town of Haigerloch.” (MSN.com/Nazi Germany was much farther from a working nuclear reactor (and a nuclear weapon) than Heisenberg claimed)

“The contraption, known as B8, was the final and most ambitious reactor experiment of Germany’s wartime nuclear program. It multiplied neutrons, but it never crossed the crucial threshold into a self-sustaining nuclear chain reaction. After the war, its lead designer, Werner Heisenberg (famous for proposing the uncertainty principle), portrayed the failure as a near miss, alluding to the fact that the Americans beat the Nazis to the nuclear bomb just slightly.”(MSN.com/Nazi Germany was much farther from a working nuclear reactor (and a nuclear weapon) than Heisenberg claimed)

“A new study suggests it was anything but.” (MSN.com/Nazi Germany was much farther from a working nuclear reactor (and a nuclear weapon) than Heisenberg claimed)

“Using surviving uranium cubes, recovered samples of heavy water, wartime industrial records and detailed computer simulations, researchers calculate that B8 would have needed roughly twice as much uranium and more than twice as much heavy water to become critical. Even if Germany had pooled virtually all the reactor materials available to its competing research groups, it still would not have worked.”(MSN.com/Nazi Germany was much farther from a working nuclear reactor (and a nuclear weapon) than Heisenberg claimed)

Production order. By Hitler was clear. All important workers and scientists who worked in German secret military projects were ordered to be shot by the SS so that their secrets would not fall into Allied hands. If. Heisenberg failed. Or if the SS thought that project was a failure. That was a death sentence. They knew too much. 

Then they needed systems to turn that plutonium into a weapon. Nazis planned to create nuclear weapons. Those weapons were Hitler's mad dream. The problem was not in technology. 

“A captured example of a Mistel trainer. United States Army personnel examined the aircraft.” (Wikipedia, Mistel)

“Ju 88H and Fw 190 combined to form a model 3B Mistel” (Wikipedia, Mistel)

“Me-262 Mistel”

“The second German pre-production Heinkel He 177A-02 Greif (DL+AQ) in flight.” (Wikipedia, Heinkel He 177 Greif)

“The Vemork plant at Norsk Hydro, Norway, after the war. The heavy water was produced in the front building, the Hydrogen Production Plant.” (Wikipedia, German nuclear program during World War II)

It was in raw materials. When Allied commandos attacked the Norsk Hydro heavy water plant in Norway in 1943, they destroyed the Heavy water line and electrolysis system. And in the follow-up operation. Much of the heavy water sank to the bottom of a lake. That happened. Because. The ferry. That transported the material was sunk by bombs. An agent was put in that ferry. 

Another Big problem was that. The graphite that the Germans had. It was not clean enough. It could. Be used to moderate that nuclear reaction. Germans made two tests there; they tried to start the core reactor. Heisenberg claimed that there was only a small amount of uranium. He said he could start the reaction. The fact is that. 

Heisenberg tried to replace the U-235 with natural uranium. He thought this would happen during the reactor core start-up tests. Or. Nuclear material in itself releases free neutrons. The number of those neutrons should be high.

So that they could maintain a self-sustaining reaction.  

This required that those neutrons could form enough Pu-239. But as we know, the nuclear material was too poor. It could not produce enough neutrons to sustain a chain reaction.  The uranium enrichment level was poor. 

So, every calculation for that project was made before the commando strike into Norsk Hydro. After that, the heavy water production ended. 

Other important raw materials were of poor quality. 

"An optimized reactor would have required about 3.1 metric tons of uranium and 3,121 liters of heavy water. B8 had only about 1.54 tons of uranium and 1,400 liters of heavy water. Even combining Germany’s estimated entire stocks would not have been enough." (Nazi Germany was much farther from a working nuclear reactor (and a nuclear weapon) than Heisenberg claimed)

This means that Heisenberg had theoretical technology. But. The problems were in enrichment processes. The separation process of the U-235 from U-238 is well known. But centrifugal separation is slower than Heisenberg expected. The Germans used weaker uranium ore. They expected. 

The Germans had carbon. But it involved too much boron. That made it useless. For. Nuclear reactor moderation. After the Norsk Hydro sabotage. The Germans couldn't create heavy water. There were theoretical plans. For. How to transport that weapon in London. One suggestion was. The He-117 "Greif" bomber. Or some jet aircraft. Equipped with an internal gun device.  Similar. That was used in the Little Boy bomb. That aircraft could be remotely controlled, flown to the target, and detonated. The system was called Super "Mistel". 

In April 1945, the reactor was ready for the first static test. The reactor couldn't start. Even. Though Heisenberg could start the core. And. Create the self-sustaining reaction. There was a long journey. To. The bomb. Germans could create only one or two bombs. And then they needed a carrier vehicle. But. That required. The nuclear material was rich enough. The system required electronic components.  

https://ahf.nuclearmuseum.org/race-bomb/

https://www.msn.com/en-us/news/other/nazi-germany-was-much-farther-from-a-working-nuclear-reactor-and-a-nuclear-weapon-than-heisenberg-claimed/ar-AA2dhK7f?ocid=BingNewsSerp

https://www.sciencealert.com/startling-discovery-shows-how-close-nazi-germany-was-to-a-nuclear-program

https://www.trendingtopics.eu/nazi-germany-atomic-bomb-uranium-study/

https://en.wikipedia.org/wiki/German_nuclear_program_during_World_War_II

https://en.wikipedia.org/wiki/Haigerloch_atomic_pile

https://en.wikipedia.org/wiki/Heinkel_He_177_Greif

https://en.wikipedia.org/wiki/Manhattan_Project

https://en.wikipedia.org/wiki/Mistel

https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage

https://medium.com/@mediuduck/how-far-nazis-were-in-their-nuclear-program-eef4c96c05fc