1. Military installations

These accidents are best understood in the tense political context of the 1950s, at the height of the race to mass-produce nuclear weapons.

• Chronologically, the first catastrophic nuclear accident, on September 29, 1957, was the so-called "Kyshtym accident" (the name of the nearest but relatively unspoiled town) in the southern Urals of the USSR. It involved a powerful chemical explosion in a high-level waste storage tank at the Mayak (Chelyabinsk-40) military-industrial complex's spent fuel reprocessing plant, the very existence of which was a state secret. The accident was kept secret for 32 years, and it was only in 1989 that the Soviet authorities made certain details of the accident public.

  It is estimated that around 74,000 TBq (2 MCi) of activity was projected aloft by the chemical explosion of superheated...