The third mistake was that, because the workers were allowed to bypass the time-consuming mixing process in the tower, with its automatic controls for preventing such things happening, they were free to dump their material into a vessel that was not designed to prevent the accumulation of a critical mass sufficient to support a chain reaction.

ECONOMIST: All over in a flash

Made of hardened steel that is between four and eight inches thick, the integrity of the containment vessel is critical in preventing enormous quantities of radioactive material from escaping into the environment.

FORBES: New Video From Fukushima Shows Containment Vessel Dome Amid Debris

The material, which was loaded on a schooner sailing vessel, will be sculpted into a piece of art called Nowhere Island.

BBC: Nowhere Island Olympic art team head home