The Peculiarities of the German Uranium Project (1939–1945)
Round 1
Reviewer 1 Report
I read with great interest this work. I think this is an interesting contribution to the understanding of the nuclear research in Germany in WWII, which is still too much polluted by the original evaluation carried during the war and soon after especially the opinion of Samuel Goudsmit.
I disagree however on few points. First, that rejecting graphite as a moderator was an error. It is my understanding the getting a graphite pure enough was not an easy task. Indeed, the whole Anglo Canadian effort in the Montreal Laboratory relied on the heavy water even if before Laurence and other Canadian members of the group build an assemble using uranium and carbon as a moderator (Reed 2021).
I recommend the publication of this article with more discussion on this aspect. I also found some minor error and commented on some minor points that need more explanation.
Line 206 : The text refer to element 94 wich is not discussed in the previous section
Line 358 : Walther Bothe. It took six years until he could start its operation in the autumn of 1944.
Goudsmit in Alsos recall the interrogation of Bothe. He had time to make numerous scientific research on his cyclotron. And after the defeated admitted having carried some work on uranium. Therefore, I have some doubt they would the time to do all this before march 19, 1945 the day Alsos took control of his laboratory.
Line 385 : Houghton (2013) report that according to the US intelligence this should have been a 200 MeV; twice as powerful than the 100 MeV cyclotron in construction at Berkeley.
Line 391 : According to Low (2006) it was 4 cyclotrons. The American soldier destroyed another device.
Line 470-473 : Historical source claimed it was more 1100 t, that was shipped in Germany (Houghton 2013). This would also contradict the recovered amount by the soviet (Oleynikov 2000).
Line 488: “Cold ice” I think this should have been CO2 ice.
Line 514-518 : As I said previously, producing very pure graphite might have been a technical challenge.
Line 663 : I am no expert in nuclear reactor physics, but I was under the impression that the reactivity increased from the unburned state until a significant fraction of the uranium is burned.
Reference
Houghton, V. (2013). The Principal Uncertainty: US Atomic Intelligence, 1942-1949 (Doctoral dissertation).
Low, M. F. (2006). Accelerators and politics in postwar Japan. Historical studies in the physical and biological sciences, 36(2), 275-296.
Oleynikov, P. V. (2000). German scientists in the Soviet atomic project. The Nonproliferation Review, 7(2), 1-30.
Reed, B. C. (2021). An inter-country comparison of nuclear pile development during World War II. The European Physical Journal H, 46(1), 15.
Author Response
Thank you for your commentary and useful comments.
The decision against carbon as a moderator is poorly founded. We quote a post-war letter of Siemens-Plania saying that it would not have been a problem, a cautious wording by Heisenberg and the official statement of the HWA. The decision could have been a mistake or a way to create a welcome delay.
On Bothe: we say that about 75% of the Uranium Project was on pure science. His FIAT paper about the war-related work raises a number of questions that we cannot comment in this publication.
358: The cyclotrons would have had enough power.
391: Groves talked about 5, we change now to 4 cyclotrons and quote Low.
470-73: Without knowing what the 1100 t was precisely, our figure of 844 t of pure U3O8 may be correct. Oleynikov says that 300 t of ‘uranium oxide and its compounds’ was shipped to the Soviet Union, and that is too imprecise to contradict the statement.
488: CO2-ice, OK.
663: Heisenberg's self-regulation can only work in an assembly that is just critical. A reactor must contain much more fissile material than a critical mass to make up for the nuclei consumed by fission.
Reviewer 2 Report
This is an excellent article. It builds upon their previous work in this journal and upon a small body of work on the wartime German nuclear programme that has been written over the last 30 years. The new research and contributions here are excellent. The one change I'd suggest is to include more references to existing scholarship on the subject because it really isn't obvious at times what is new and original in the article.
Author Response
Thank you for your acknowledgements. Your recommendation to refer more often to existing scholarship is difficult to fulfill. The peculiarities were also observed by earlier authors, may be not all of them by all authors. What is entirely new is our interpretation that the presumed "failures" were made intentionally to avoid a transition to a large military program.
Reviewer 3 Report
please see attached.
Comments for author File: 
Comments.pdf
Author Response
Thank you for your acknowledgements and comments.
Your main question concern the central message of our publication. We will add after 391:
As a result of the fragmentation of the work-force, there was no discussion of the strategy to proceed among the scientists, because there was a lack of occasions and a reluctance by those living far from Berlin to speak up without sufficient knowledge of the official line. That made it easy for Heisenberg and Diebner to steer the project. There was no collusion of the scientists, their majority rather preferred to abstain from expressing critique or making proposals. They were content with their privileged situation and did not want to jeopardize it. Details: 223-226: we leave the digital counting aside 413-416: New: Compared to the time needed for these steps in the Manhattan Project, the Germans could have spent two years more for building much smaller facilities 481: that were needed to establish a self-sustaining reaction. 619: balm 738-39: we combine the two fragmentary sentences.
