Nuclear Blasting

7.5-1. introduction. The possible engineering uses of nuclear explosives were recognized with the first nuclear detonation. Subsequent experiments have demonstrated the ability of nuclear explosives to move very large volumes of rock and earth efficiently and at costs below conventional earth-moving methods. The ability to package a quantity of energy equivalent to a few million tons of conventional explosive in a container approximately 20 ft long and 36 in. in diameter enables easy emplacement and thus provides the potential for excavation on scales heretofore impossible. Space does not permit detailed discussion of the many experiments with conventional high explosives and with nuclear explosives that were performed in developing the information presented here. A bibliography is included for those wishing detailed information. Material from those sources and from personal experience has been used freely. 7.5-2. Nuclear Explosives. An explosion, in general, results from the very rapid release of a large quantity of energy within a limited space. This is equally true for both conventional and nuclear explosions, although the energy is produced in quite different ways. In the case of a conventional explosive, this energy arises from chemical reactions. In a nuclear explosion, the energy is produced as a result of the formation of different atomic nuclei by the redistribution of the protons and neutrons within the interacting nuclei. Nuclear energy is of a much higher order of magnitude than chemical energy when equal masses are considered, and the release of this energy is a thousand times more rapid than the fastest chemical detonations. Explosions may be produced by fission or fusion reactions. FISSION. When a free (or unattached) neutron enters the nucleus of a fissionable atom, it can cause the nucleus to split into two smaller parts. This fission process is accompanied by the release of a large quantity of energy. The complete fission of 1 lb of uranium can produce as much energy as an explosion of 9,000 tons of TNT.