Analysis of surviving uranium cubes clarifies failure of Nazi nuclear reactor program

Researchers analyzed two surviving uranium cubes from the World War II German nuclear initiative to determine why researchers failed to achieve nuclear criticality. Ars Technica reported that Timothy Koeth, Miriam Hiebert, and their co-authors re-examined historical records, technical reports, and physical artifacts to evaluate the experimental efforts of the German research teams. [1][2]

The research builds on earlier findings involving a box of declassified documents located in the National Archives. According to Ars Technica, these documents revealed that a separate research group in Gottow possessed roughly 400 additional uranium cubes. If the Gottow inventory had been combined with the material used in the Berlin B-8 reactor experiment, the German scientists would have possessed sufficient material to reach criticality. [1][2]

The Nazi nuclear program, known as the Uranverein or Uranprojekt, began in April 1939 following the discovery of nuclear fission in Berlin. A second research push was reorganized under the Heereswaffenamt on September 1, 1939. Ars Technica reported that the latest paper reaches a new conclusion regarding the failure, indicating that Werner Heisenberg significantly underestimated the amount of uranium required for a working reactor. [1][2][3]

The findings show how secretiveness and lack of cooperation hindered scientific progress. Ars Technica reported that the isolated, secretive approach of the competing German groups prevented them from sharing resources, which ultimately stalled their development of a functional nuclear reactor. [1][2]