Thin Man (nuclear Bomb) - Specifications

Specifications

The "Thin Man" design was an early nuclear weapon design proposed before plutonium had been successfully bred in a nuclear reactor from the irradiation of uranium-238. It was assumed that plutonium, like uranium-235, could be assembled into a critical mass by simply shooting one sub-critical piece into another. To avoid pre-detonation, a plutonium "bullet" would need to be accelerated to a speed of at least 3,000 feet per second (910 m/s)—or a fission reaction would begin before the assembly was complete, blowing the device apart prematurely.

The Mark 2's estimated diameter was 2 feet (0.61 m) and its length 18 feet (5.5 m); the length was necessary for the plutonium "bullet" to pick up adequate speed before reaching the "target". Weight was estimated at 7,500 pounds (3,400 kg) for the final weapon model.