Fall-out over Australia from Nuclear Weapons tested by France during July 1966

Abstract

FRENCH nuclear weapons testing, at a site in the Tuamotu Archipelago in the South Pacific Ocean, started in July 1966 with low-yield explosions in the atmosphere at 1534 G.M.T. on July 2, and 1505 G.M.T. on July 19. A third test on July 21 was described as a safety experiment and did not involve a nuclear reaction, while the fourth test in the series did not occur until September 11. Before these tests, fall-out over Australia comprised only very low concentrations of aged debris from the stratosphere arising from high yield atmospheric tests carried out before the partial Test Ban Treaty of 1963. Because of this situation, there could be unambiguous detection of fresh fission products arriving from the first two French tests of July 2 and 19. Preliminary results obtained from the Australian fall-out monitoring network are briefly reported and discussed here for the period July 1 to September 15. Fall-out over Australia from the first two explosions was virtually complete by September 15, while debris from the fourth test had not reached Australia.