#Nazis #nukes #Heisenberg
"Nazis and the bomb: nuclear archaeology finds Werner Heisenberg mistook how close he was
Scientists have found that the Nobel laureate may have grossly overestimated how close his team was to having a working nuclear reactor, much less a nuclear weapon.
(. . .)
The Manhattan Project tested its first atom bomb on July 16, 1945, and delivered two to the U.S. military in July-August. Part of their sense of urgency was rooted in doubts about whether Nazi Germany was also building a bomb, including an effort led by physicist and Nobel laureate Werner Heisenberg. Their anxieties were not unfounded: in April 1945, only weeks before Germany surrendered to Allied forces, Heisenberg’s team had assembled a nuclear reactor in a cellar beneath a church in Haigerloch, in the country’s south.
The setup, called the B8 pile, had 664 cubes of uranium suspended on chains in around 1,400 litres of heavy water. A 40-cm-thick shell of graphite surrounded the core, and was itself surrounded by a layer of aluminium and a 60-cm-thick layer of (ordinary) water. Heisenberg’s team had taken six years to build B8 but had little to show for it. When a few neutrons were shot into the reactor, the uranium multiplied them into more — but no chain reaction followed.
Far from critical
After the war ended, Heisenberg said the team had
come very close; he wrote in a 1947 article in Nature that Haigerloch didn’t have enough resources and that just a little more quantity of uranium would have done the trick.
According to a new study in PNAS Nexus, by researchers from the U.S., Heisenberg & co. were actually way off the mark."
https://archive.ph/6s9xG#selection-1869.0-1869.526