Uranianism

“ When a neutron strikes the nucleus of uranium-235 (235U) or plutonium-239 (239Pu) , it may cause the nucleus to split into two roughly equal fragments, releasing neutrons and energy. This is the well-known process of neutron-induced fission, the method in which nuclear energy is produced in both reactors and bombs. [14] The most common uranium isotope, 238U, also breaks up by fission, but does so all by itself, without the need for any external neutrons. That process is spontaneous fission and it goes on at random, very much like radioactive decay. ”

“ They could have destroyed the other nations of the world, and the others were so well aware of it that they have not since risked the science of fission, still dreading the rain of warheads that might come screeching through the Atomic Curtain. Even today, although a century and a half has passed, we're still so obsessed with that dread that we maintain the International Patrol, ceaselessly flying the outer fringe of radiation in the stupid hope that if that rain of warheads comes, we shall have a warning of it. ”

“ The lead-210 will then decay with its 22-year half-life.”
The radioactive series that starts with uranium is like a series of lakes connected by waterfalls. As long as uranium, the big one on top, has water in it, the others will be full and the falls will keep flowing. ”

“ I was too close to the atom-rocket. My conductor screen grazed the warhead itself!
Its energies surged through the unstable elements in the warhead; a warning bell sprang into clamorous life. The group around me froze in their tracks, mouths open, faces mirroring fright and disbelief—and the frightful power of the strained atoms within the warhead began to grind toward nuclear fission! ”

“ This was the only chance and here, between the hidden place where determined men had worked tirelessly and ingeniously to refine only a small capsule of pure Uranium in a year and the hidden place where other learned men waited to incorporate the product into an atomic bomb that could destroy the city of the invaders completely, lay the greatest danger of defeat. ”

“ You know, most of the wars they've been fighting, lately, on the Europo-American Sector have been, at least in part, motivated by rivalry for oil fields. But now that the Europo-Americans have begun to release nuclear energy, fissionables have become more important than oil. In less than a century, it's predicted that atomic energy will replace all other forms of power. Mineral Products Syndicate wanted to get a good source of supply for uranium, and your Proto-Aryan Sector franchise was worth grabbing. ”

“ If a chain reaction could be started in a sizable piece of uranium, unimaginable quantities of energy would be produced. Just 1 gram of uranium, undergoing complete fission, would deliver the energy derived from the total burning of 3 tons of coal and would deliver that energy in a tiny fraction of a second.
Szilard, who had come to the United States in 1937, clearly visualized the tremendous explosive force of something that would have to be called a “nuclear bomb”. ”

“ Now you have lost completely, Hohmann, for the radiation from that paper when bombarded with the plutonium radiation, produces a whole string of secondary radioelements in your offices, in your desks, in your bodies, and in your air. The ash from burning is still hot, Hohmann, and the trucks that will carry the deadly paper will be as deadly. Your very country will be subject to slow fission if you start another uranium pile for several hundred years. ”

“ The world appeared to have far greater sources of energy than had been expected. The “fossil fuels”—coal, oil and natural gas—were being used at such a rate that many speculated that the gas and oil would be gone in decades and the coal in centuries. Was it possible that uranium might now serve as a new source that would last indefinitely?
It was rather disappointing that it was uranium-235 which underwent fission, because that isotope made up only 0.7% of the uranium that existed. ”

“ But, surrounded by a shield through which no neutron could escape, any mass of material on earth would become an atomic pile!
A single molecule of uranium in any mass of rock will sooner or later disintegrate, giving off high-speed neutrons. Normally they travel indefinitely and are harmless. Some go up into the air and may ionize a single molecule. Some may find a fissionable atom and disrupt it. ”

“ Whereas, the DU weapons not only penetrate armor and other hardened targets, but also burst into flames releasing quantities of aerosolized uranium particles into the environment that are easily carried by wind or water and are easily resuspended, blowing radioactive contamination to locations quite distant from battlefield locations ”

“ Then, in March 1941, the element plutonium was isolated, and the plutonium-239 isotope was found to fission as readily as the scarce uranium isotope, uranium-235. The plutonium, produced in a uranium-fueled nuclear reactor, provided the United States with an additional source of material for nuclear weapons (7; 12) .
In the summer of 1941, the British Government published a report written by the Committee for Military Application of Uranium Detonation (MAUD) . This report stated that a nuclear weapon was possible and concluded that its construction should begin immediately. ”

“ Nuclear energy has at last enabled us to realize the predictions of Jules Verne’s adventure tale, Twenty Thousand Leagues Under the Sea, and to build a true submarine—a craft whose submerged existence is limited only by the physiological and psychological endurance of its human crew. This fact in itself has added greatly to our need to learn much more about the ocean, for the sea is an opaque and strange environment in which the deadly game of hunt-and-be-hunted will be won by whoever knows the ocean best.
The very fact that we have nuclear energy means we have nuclear wastes ”

“ The range of the plutonium radiation is unknown, but it is great enough to bathe the entire country. You will find that most government offices are bulging with reams and reams of correspondence, many of which are over the critical mass. Nothing happens until someone turns on a plutonium-producing uranium pile, lets it run for a few hours, and the accumulation of plutonium starts. Right now, Hohmann, you have about four hours before most of your government offices go sky-high—from their own red tape. ”

“ Occasionally the random quivering of a nucleus would bring about a shape that the nuclear interaction could not bring back to normal and the nucleus would then break apart. In a gram of ordinary uranium, there is a nucleus undergoing such “spontaneous fission” every 2 minutes on the average. Therefore, enough uranium need only be brought together to surpass critical size and it will explode within seconds, for the first nucleus that undergoes spontaneous fission will start the chain reaction. ”

“ If all the energy delivered by a gram of uranium in the course of its radioactivity over many billions of years was totalled, it was enormously greater than the energy produced by the burning of a candle with a mass equal to that of uranium. ”

“ By 1910 it was well established that the earth must be extremely ancient. Analyses of some minerals containing uranium showed them to be hundreds of millions of years old, even though the uranium came from rocks that were known to be relatively young among geologic STRATA. Measurements still were inaccurate, however, and only a few rare and unusually rich radioactive minerals contained enough of the products of RADIOACTIVE DECAY [2] to allow analysis of their age by the crude methods then available. ”

“ We could not assume that the Soviet Union would not develop the same weapon, regardless of all our precautions, nor that there were not other and even more terrible means of destruction lying in the unexplored field of atomic energy. ”

“ In this respect, as in some others, the universe seems like a clock running down, with no mechanism for winding it up again. All the uranium in the world is breaking down, and we know of no source from which new uranium can come. Under these circumstances it seems strange that there should be any uranium. But if, like some insects, we lived only for a single spring day, we should think it strange that there should be any ice in the world, since we should find it always melting and never being formed. ”

“ Therefore it seems to us important to start production as soon and as rapidly as possible, even if it is not intended to use the bomb as a means of attack. Since the separation of the necessary amount of uranium is, in the most favourable circumstances, a matter of several months, it would obviously be too late to start production when such a bomb is known to be in the hands of Germany, and the matter seems, therefore, very urgent. As a measure of precaution, it is important to have detection squads available in order to deal with the radioactive effects of such a bomb. ”

“ The rays that get out strike the uranium plate and cause the surface layer of molecules to disintegrate, their products being driven off by the atomic explosions with a velocity about equal to that of light, and it's the recoil that deflects and swings the plate. The amount of uranium decomposed in this experiment couldn't be detected by the most delicate balance—small mass, but enormous velocity. See?"
"Yes, I understand," answered Thornton. "It's the old, 'momentum equals mass times velocity,' business we had in mechanics." ”

“ But at present no man knows, no man has an inkling of how this little lump of stuff can be made to hasten the release of its store. It does release it, as a burn trickles. Slowly the uranium changes into radium, the radium changes into a gas called the radium emanation, and that again to what we call radium A, and so the process goes on, giving out energy at every stage, until at last we reach the last stage of all, which is, so far as we can tell at present, lead. ”

“ Teena said.
“Well, the reactor is about four stories high,” Eddie went on. “They call it a uranium ‘pile.’ It’s made up of hundreds and hundreds of graphite bricks. That’s where they get the name ‘pile’—from brick pile. Anyway, scattered around in between the bricks are small bits of uranium. Uranium atoms are radioactive. That is, they keep splitting up and sending out rays.”
“Why do they do that?” Teena asked.
37
“It’s just the way nature made uranium, I guess,” Eddie said. “Most atoms stay in one piece, although they move around lickety-split all of the time. ”

“ The substance which I obtain from uranium is so concentrated that I can carry in my pocket all that will be required to repair the damage done to the transformers in the car. A careful examination, which I have made of the car, proves that the terrific shocks the machinery suffered in the crystal mountains caused an atomic readjustment which destroyed the usefulness of the material in the transformers, and while I might, by laboratory treatment, possibly restore its properties, I think it safer to obtain an entirely fresh supply. ”

“ It might take another year or two years, but the invaders would learn that Earthmen don't give up easily. A way would be found!
Then it happened; the thing that made Winston Eberly curse and sweat and retract his noble thoughts. There would be no pitiful steam-powered dirigible or any other weapon carrier. What need for one, when the bomb, itself, would never be completed? The men waiting for the Uranium were never going to see it! ”

“ The one per cent of argon found in the earth’s atmosphere comes almost entirely from the second reaction. These radioactivities are also interesting because appreciable amounts of potassium40 are always present in human tissue.
All nuclei at the heavy end of the periodic system are radioactive alpha emitters. Uranium, for example, has no stable isotopes; they all undergo alpha decay. But there is another 46 mode of spontaneous decay of uranium, which is much less frequent than alpha decay but is of much greater practical importance. This is the fission process. ”

“ In uranium, we have the one obvious derivative uranium-X, and the question remains whether this one descent can be connected with any other individual or family. Uranium is long-lived, and emits only alpha-rays. Uranium-X decays to half value in 22 days, giving out beta- and gamma-rays. Since our evidence goes to show that radio-activity is generally accompanied by the production of new elements, it is natural to search for the substance of uranium-X in other forms, and perhaps under other names, rather than to surrender immediately our belief in the conservation of matter. ”

“ While atomic research had remained in the uranium fission stage, the vast laboratory facilities of Earth had not endangered humanity. Even the first atomic bombs had not placed an intolerable strain on man's capacity to survive the hazards of working together toward a shared goal. ”

“ One isotope of plutonium, plutonium-239, which resulted from the absorption of a neutron by a 238U nucleus and the emission of two beta particles, was discovered to be as fissionable as 235U and hence theoretically just as feasible for a bomb. Since plutonium is chemically different from uranium, it offered the tremendous advantage that it could readily be concentrated by conventional chemical techniques.
The way to manufacture usable amounts of plutonium, an element that had never before been detected on earth, is to expose uranium to a very intense neutron bombardment. ”

“ However, such bombs might very well prove to be too heavy for transportation by air.
The United States has only very poor ores of uranium in moderate quantities. There is some good ore in Canada and the former Czechoslovakia, while the most important source of uranium is Belgian Congo. ”

“ This can, for obvious reasons, lead to serious instability in the overall system—most interesting systems cannot withstand the unbounded increase of any of their parameters without serious negative consequences. The basic engineering principles underlying the creation of nuclear weapons exploit this feature of positive feedback mechanisms: the destructive output of nuclear weapons results from the energy released during the fission of certain isotopes of (in most cases) uranium or plutonium. ”