The primary ignition sources appear to be flames and pilot lights in heating appliances (furnaces, water heaters, stoves, ovens, etc.). Most probably not. Atom bombs have a power equivalent to millions of tons of ordinary explosive. Only authorized host sites may make this document publicly available on the Internet through the World Wide Web, anonymous FTP, or This strength in numbers advantage to lower yield warheads is further compounded by such warheads tending to move at higher incoming speeds, due to their smaller, more slender physics package size, assuming both nuclear weapon designs are the same (a design exception being the advanced W88). Military equipment is generally designed to be resistant to EMP, but realistic tests are very difficult to perform and EMP protection rests on attention to detail. It isn't clear who proposed a 100-megaton bomb—Khrushchev or the weaponeers—but at the premier's command the most powerful nuclear weapon ever built had to be ready in only four months. By contriving a subcritical arrangement of fissionable material whose average density can be rapidly increased, we can bring about the sudden large increase in reactivity needed to create a powerful explosion. Normal pigmentation may take months to return. Immediately after the explosion, there are substantial amounts of fission products with very short half-lifes (milliseconds to minutes). The most intense radiation is created by nearby fallout, because it is more densely deposited, and because short-lived isotopes haven't decayed yet. This is a less intense type of fire, it develops and burns more slowly. As soon as the sphere expands beyond the bomb casing it begins radiating light away through the air (unless the bomb is buried or underwater). They are the hardest to stop with shielding. The firestorm in Hiroshima began only about 20 minutes after the bombing. However two caveats apply: Acute Localized Tissue Exposure. 50% of the 200–450 rems group will die within two to four weeks, even with medical attention. It is estimated that the dose to reproductive tissue required to double the natural incidence of genetic disorders is 100-200 rems. When an area is contaminated by gamma emitting isotopes, a radiation field is created that exposes all organisms that are not shielded from it. The formation EMP begins with the very intense, but very short burst of gamma rays caused by the nuclear reactions in the bomb. The rapid drop in temperature causes the thermal power to drop ten-fold, reaching a minimum in about 10 milliseconds for a 20 kt bomb (100 milliseconds for 1 Mt bomb). However, it is very difficult to handle nuclear waste. Immediate disorientation and coma will result, onset is within seconds to minutes. As this incandescent ball of hot gas expands, it radiates part of its energy away as thermal radiation (including visible and ultraviolet light), part of its energy also goes into creating a shock wave or blast wave in the surrounding environment. After 7*2 days (2 weeks) it drops a further 90%; and so on for 14 weeks. The range for blast effects increases with the explosive yield of the weapon and also depends on the burst altitude. For two years while their country joined the United States and the United Kingdom in a voluntary moratorium on nuclear tests, Soviet nuclear scientists, including Andrei Sakharov, the “father of the Soviet hydrogen bomb,” developed and refined new weapon concepts and designs. As yields increase above 100 kt, progressively more and more of the total fallout is injected into the stratosphere. An additional benefit is that through reactions 5 and 6, the lithium can itself participate in the fusion reaction. For a given explosion yield, and a given blast pressure, there is a unique burst altitude at which the area subjected to that pressure is maximized. After this a 7-14 day latency period sets in. Since the D+T reaction rate is so high, and there is large excess of deuterium, the tritium is consumed almost as fast it is produced. The fusion reactions that occur in stars are not the same as the ones that occur in thermonuclear weapons or (laboratory fusion reactors). [10] There is no sharp cutoff to distinguish acute exposures from chronic (extended) ones.