Science TechnologyTuesday, 6 October 2026·The Hindu - International
Heisenberg and Nazi Germany’s B8 pile: key nuclear archaeology facts for science current affairs
A new study in PNAS Nexus revisited Werner Heisenberg’s B8 reactor pile at Haigerloch and found Nazi Germany was far from achieving criticality.
Key highlights
Direct fact
In a new PNAS Nexus study discussed in 2026, researchers revisited Werner Heisenberg’s B8 pile at Haigerloch, Germany, and concluded that Nazi Germany’s wartime reactor effort was far from reaching criticality.
Key specifics
- The B8 pile had 664 uranium cubes suspended on chains in around 1,400 litres of heavy water.
- The reactor core was surrounded by a 40-cm-thick shell of graphite, then aluminium, and a 60-cm-thick layer of ordinary water.
- The team estimated a neutron multiplication factor of 0.942, while a critical reactor needs a factor of 1.
- Researchers said B8 would have needed at least 2,994 kg of uranium and 3,411 litres of heavy water to become critical.
- The dismantled B8 pile contained 1,538 kg of uranium and 1,549 kg of heavy water, showing a major shortfall.
Exam lens
Question type: Science and technology, nuclear physics facts, reactor criticality, heavy water and uranium quantities; TNPSC may ask what factor defines criticality and where the B8 pile was assembled, i.e., Haigerloch.