shielding (cont'd) of fissionable and ‘radicxctive materials, 2. Obstructions which tend to protect personnel or materials from the effects of an atomic explosion, shock wave The continuously propagated pressure pulse formed by the blast from an explosion -in air by the air blast, underwater by the water blast, and underground by the earth blast, It is a pressure wave in the surrounding medium initiated by the expansion of the hot gases produced after the explosion, There are two phases to the shock wave: the positive and negative, During the positive phase the pressure rises abruptly to a pressure usually considerably higher than normal atmospheric pressure, and then declines rapidly. The duration of the positive phase is usually about half that of the subsequent negative phase, During the negative phase, the ambient pressure is reduced below atmospheric pressure. stockpile-to-target sequence The order and permutations of events involved in removing an atomic weapon from storage and assembling, testing, transporting, and delivering it to the target, TACAN Tactical air control and navigation system capable of presenting positioning information to the pilot within one degree of accuracy in azimuth and one per cent accuracy in range, thermonuclear . An adjective referring to the process involving the fusion of light nuclei such as those of deuterium and tritium, toroidal circulation The circulation in the atomic fireball develogs a doughnut-shaped form, with an updraft in the middle and a downdraft around the outside, TX A generic prefix to the number which designates the specific developmental model of a new atomic weapon. When the weapon reaches the production stage the TX designation is changed to a Mark or MK prefix. 328 AFWLHO SWEH -2-003) Bal...