On February 13 , 1960 at 6:04 AM ( GMT ) , the plutonium filled Gerboise Bleue was detonated atop a steel tower with an altitude of 100m . The command post was located 16 kilometers away from the blast . In order to study the immediate effects , military equipment was placed at varying distances from the epicenter , while jets flew overhead to take samples of radioactive particles . No journalists were allowed on site ; instead , an eyewitness account was given to the French press , saying “ the desert was lit up by a vast flash , followed 45 seconds later by an appreciable shock-wave ; an “ enormous ball of bluish fire with an orange-red centre ” gave way to the typical “ mushroom ” cloud ” With Gerboise Bleue , France became the fourth nuclear power , after the United States , the USSR , and the United Kingdom . Prior to this test , there had been no nuclear detonations for 15 months . Gerboise Bleue was by far the largest first test bomb up to that date , larger than the American " Trinity " ( 20 kt ) , the Soviet " RDS-1 " ( 22 kt ) , or the British " Hurricane " ( 25 kt ) . The yield was 70 kilotons , bigger than these three bombs put together
Hurricane
Operation Hurricane
Gerboise Bleue