Post by Oil exporting People on Oct 9, 2020 5:07:58 GMT
The historical German effort was pretty much a disaster. Underfunded and with around 20 separate projects or so (including the famous one by the German Post Office), it was already off to a bad start but ultimately ran into complete disaster in 1940. Although they essentially figured out Plutonium at this point and then confirmed it in 1941 through the theoretical work of Fritz Houtermans, a combination of miscalculations by both Heisenberg and cohorts at the Kaiser Wilhelm Institute combined with measurements conducted by Hans Bothe lead to the conclusion graphite would not work as a moderator; they had failed to grasp, due to imprecise data, the need for ultra pure graphite and ultimately went with Heavy Water. This was further combined later on with their failure to grasp what was needed for critical mass, and the famous Allied efforts against their Heavy Water facilities in Norway.
However, despite all of this, there wasn't anything structural or insurmountable in the way of the Reich obtaining nuclear weapons from my estimation. The V-2 program cost about $2 Billion, the same as the Manhattan Project and a spate of better luck probably could've prevented the Heavy Water debacle in favor of using graphite. Heisenberg was also able to figure out the amount needed for critical mass in the immediate days following the Atomic bombings of Hiroshima and Nagasaki based off what news reports they could get and redoing his calculations. Given that, it seems like a lucky break or two would've been sufficient to put their program on track and with that they could've probably got the needed funding since they'd have better prospects of near term production to entice such. Here's a timeline of events mostly sourced from The Critical Mass by Jonothan Logan in American Scientist, Vol. 84, No. 3 (MAY-JUNE 1996), pp. 263-277
May 1, 1939 - Francis Penin in Paris publishes a calculation of the minimum mass of natural uranium for a chain reaction: 40 tons of uranium oxide, possibly reducible to 12 tons with a neutron reflector. In a paper two weeks later he concludes that a slow-neutron chain reaction will require only 5 tons.
December, 1939 - Rudolf Peierls in Birmingham publishes an improved calculation of the critical mass, extending Perrin's results to neutron multiplication not small compared to 1; results are stated as general formulas. The article presumably did not reach Germany due to the onset of the war, and the calculations led directly to the realization of about 10 kilograms or less of U235 was needed for bombs.
February 29, 1940 - Heisenberg submits to German Army Weapons the second part of his report dealing with slow neutron chain reactions; he rejects graphite as a moderator.
January 20, 1941 - Walther Bothe and Peter Jensen in Heidelberg measure the neutron absorption cross section of graphite and mistakenly conclude that graphite can not be an effective moderator.
August, 1941 - Fritz Houtermans submits to the German Post Office a report including a critical mass formula like Perrin's but without quantitative estimates, and the suggestion that fissionable plutonium will be generated in a reactor. Houtermans' work gains little attention.
1941 was clearly the decisive year of German nuclear research, as they doubled down against graphite with the ultimate ramifications that being known and Houtermans work, which very nearly came close to solving both the critical mass errors made as well as putting them on the path to a plutonium bomb, was ignored. The easiest way would be to go further back. Basic idea for the ATL could go something like this:
May, 1939 - Paul Harteck stumbles upon Perrin's article and is able to figure out critical mass like Peierls essentially did; the information is shared with Heisenberg. The adopting of the neutron reflector also allows for safety procedures to enter into the nascent German program.
September, 1939 - Heisenberg's first report is submitted, and immediately raises the interest of the German ordnance bureau due to the bomb appearing far more likely. The need to consider a moderator leads to them making the funds available to test for such.
February, 1940 - Walther Bothe and Peter Jensen at Heidelberg are able to confirm that ultra pure graphite can be used as a moderator. With this confirmation, intensive funding and research begins.
Summer, 1940 - Fritz Houtermans produces the research needed to make the plutonium design possible.
August, 1941 - German reactor, in the same vein as Chicago pile, comes online.
October, 1944 - First German nuclear bomb.
The first Allied bomb was available two years and 7.5 months after Chicago Pile-1 came online. Here, the Germans get their first one after three years and two months, so about an extra year of development due to funding/resource issues. Honestly, I could be too conservative with this, as up until the time to build the reactor comes most of the work is theoretical and could thus be expedited. You could move most of the events up by several months more than I did, but I'm erring on the side of caution.
However, despite all of this, there wasn't anything structural or insurmountable in the way of the Reich obtaining nuclear weapons from my estimation. The V-2 program cost about $2 Billion, the same as the Manhattan Project and a spate of better luck probably could've prevented the Heavy Water debacle in favor of using graphite. Heisenberg was also able to figure out the amount needed for critical mass in the immediate days following the Atomic bombings of Hiroshima and Nagasaki based off what news reports they could get and redoing his calculations. Given that, it seems like a lucky break or two would've been sufficient to put their program on track and with that they could've probably got the needed funding since they'd have better prospects of near term production to entice such. Here's a timeline of events mostly sourced from The Critical Mass by Jonothan Logan in American Scientist, Vol. 84, No. 3 (MAY-JUNE 1996), pp. 263-277
May 1, 1939 - Francis Penin in Paris publishes a calculation of the minimum mass of natural uranium for a chain reaction: 40 tons of uranium oxide, possibly reducible to 12 tons with a neutron reflector. In a paper two weeks later he concludes that a slow-neutron chain reaction will require only 5 tons.
December, 1939 - Rudolf Peierls in Birmingham publishes an improved calculation of the critical mass, extending Perrin's results to neutron multiplication not small compared to 1; results are stated as general formulas. The article presumably did not reach Germany due to the onset of the war, and the calculations led directly to the realization of about 10 kilograms or less of U235 was needed for bombs.
February 29, 1940 - Heisenberg submits to German Army Weapons the second part of his report dealing with slow neutron chain reactions; he rejects graphite as a moderator.
January 20, 1941 - Walther Bothe and Peter Jensen in Heidelberg measure the neutron absorption cross section of graphite and mistakenly conclude that graphite can not be an effective moderator.
August, 1941 - Fritz Houtermans submits to the German Post Office a report including a critical mass formula like Perrin's but without quantitative estimates, and the suggestion that fissionable plutonium will be generated in a reactor. Houtermans' work gains little attention.
1941 was clearly the decisive year of German nuclear research, as they doubled down against graphite with the ultimate ramifications that being known and Houtermans work, which very nearly came close to solving both the critical mass errors made as well as putting them on the path to a plutonium bomb, was ignored. The easiest way would be to go further back. Basic idea for the ATL could go something like this:
May, 1939 - Paul Harteck stumbles upon Perrin's article and is able to figure out critical mass like Peierls essentially did; the information is shared with Heisenberg. The adopting of the neutron reflector also allows for safety procedures to enter into the nascent German program.
September, 1939 - Heisenberg's first report is submitted, and immediately raises the interest of the German ordnance bureau due to the bomb appearing far more likely. The need to consider a moderator leads to them making the funds available to test for such.
February, 1940 - Walther Bothe and Peter Jensen at Heidelberg are able to confirm that ultra pure graphite can be used as a moderator. With this confirmation, intensive funding and research begins.
Summer, 1940 - Fritz Houtermans produces the research needed to make the plutonium design possible.
August, 1941 - German reactor, in the same vein as Chicago pile, comes online.
October, 1944 - First German nuclear bomb.
The first Allied bomb was available two years and 7.5 months after Chicago Pile-1 came online. Here, the Germans get their first one after three years and two months, so about an extra year of development due to funding/resource issues. Honestly, I could be too conservative with this, as up until the time to build the reactor comes most of the work is theoretical and could thus be expedited. You could move most of the events up by several months more than I did, but I'm erring on the side of caution.
