Following the 1966 Palomares B-52 crash and the 1968 Thule Air Base B-52 crash , accident investigators concluded that the conventional explosives used at the time in nuclear weapons were not stable enough to withstand the forces involved in an aircraft accident . The finding triggered research by scientists in the United States into safer conventional explosives that could be used in nuclear weapons . The Lawrence Livermore National Laboratory developed the " Susan Test " — a standard test that uses a special projectile whose design simulates an aircraft accident by squeezing and nipping explosive material between metal surfaces . The test projectile is fired under controlled conditions at a hard surface to measure the reactions and thresholds of different explosives to an impact
1968 Thule Air Base B-52 crash
1968 Thule Air Base B-52 crash
Explosives safety