Radioactive emanation

“ Radioactivity is characterized by the kind of particle emitted from the nucleus (our examples, so far, have been of beta and gamma particles) , by the energy possessed by this particle, and by the half-life in which the radioactive decay takes place.
The biological hazard from radioactivity depends on all three of these characteristics. No matter whether the radioactive nuclei are produced in an atomic explosion or in an atomic reactor, some time will in general elapse before a human population can become exposed. ”

“ Particularly significant studies have been conducted of the absorption of radionuclides by plants and animals living on nearby reefs and islands, and of both lateral and vertical diffusion rates of elements in the open ocean. [8]
The 1954 nuclear test at Eniwetok Atoll produced heavier-than-expected local radioactive fallout. Since then, both 24 American and Japanese scientists have studied water-mass movement rates, using the fallout radionuclides strontium-90 and cesium-137 themselves as tracer elements. ”

“ When a nuclear weapon explodes near the ground, great quantities of pulverized earth and other debris are sucked up into the nuclear cloud. There the radioactive gases produced by the explosion condense on and into this debris, producing radioactive fallout particles. Within a short time, these particles fall back to earth--the larger ones first, the smaller ones later. On the way down, and after they reach the ground, the radioactive particles give off invisible gamma rays--like X-rays--too much of which can kill or injure people. These particles give off most of their radiation quickly ”

“ A better way to appreciate the danger from fallout is to compare it with other more familiar dangers. Such a comparison can be made with the natural background of cosmic rays and radioactivity in the earth and in our own bodies.
We are constantly and inescapably exposed to this radiation. Our ancestors have been exposed to it. The human race has evolved in such a radioactive environment. Moreover, the biological effects from different kinds of radiation can be compared in a meaningful way in terms of roentgens. Therefore the danger from Sr90 is not unknown in every respect. ”

“ In the beginning of the Atomic Era, the Deadly Radiations existed. They still exist, but they are no longer deadly, because all life on this planet has adapted itself to such radiations, and all living things are now immune to them."
"And Hradzka has returned to a time when such immunity did not exist? But would that not be to his advantage?"
"Remember, General, that man has been using atomic energy for ten thousand years. Our whole world has become drenched with radioactivity. The planet, the seas, the atmosphere, and every living thing, are all radioactive, now. ”

“ Fallout radioactivity is assessed as a potential specific hazard to human populations.
2. Conditions created by fallout are examined for their potential long-term ecological significance.
3. Radionuclides introduced into the environment by nuclear tests, reactor operations, or other means are used as trace materials in basic studies in biological systems.
4. Radioactive forms of minerals and nutrients are deliberately introduced into biosystems—in measured amounts and under conditions of control—for studies of metabolic cycles and rates of flow of energy and nutrition. ”

“ Life on earth evolved amid constant exposure to ionizing [3] radiation, from the earth itself and from space, known as 4 background radiation. Therefore environmental studies must be conducted in relation to, and with understanding of, background radioactivity.
This Pacific Ocean coconut crab, member of a family that usually sticks to tide-covered beaches, depends on coconut trees for its food.
Of some 340 kinds of atoms that have been found in nature, about 70 are radioactive. ”

“ Induced Radioactivity.—Radium, thorium, and actinium have the property of acting externally, apart from the Becquerel rays that they emit. They communicate little by little their radioactive properties to substances in their neighborhood, and the latter emit in turn Becquerel rays. The activity can be transmitted to gases, liquids, and solids. The phenomenon is known as induced radioactivity.
Induced radioactivity propagates itself in gases step by step by a sort of conduction, and is not at all due to direct radiation from the body which causes 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. ”

“ Of the 200 million electron-volts released in fission, about 10 million go into gamma rays and neutrons created in the fission process itself. This energy contributes to the immediate and local radiation danger. Another 24 million electron-volts go into radioactivity of the fission products, and of this, about half go into neutrinos, which are neither dangerous nor useful; the other half is carried by electrons and gives rise to the delayed radioactive hazard. But the bulk of the energy, over 160 million electron-volts, goes into kinetic energy of the two primary fission fragments. ”

“ A reactor accident conceivably could add a unique hazard since neutron radiation might change the normally stable, nonradioactive atoms in the bodies of nearby workers into radioactive ones. Even gold or silver fillings in their teeth might become radioactive. ”

“ After the storage period, the gas is pumped into an array of instruments known as a low-background PROPORTIONAL COUNTER, and its radioactivity is determined. This is an involved process. First there is the matter of the BACKGROUND COUNT.
The background count of an instrument is the number of pulses (counts) it will give per unit time when there is no radioactive sample in it. These counts are caused by cosmic rays, by radioactive contamination always found in the vicinity of the counter, or by any contamination inside the instrument. ”

“ All nuclear explosions cause light, heat and blast, which occur immediately. In addition, explosions that are on or close to the ground would create large quantities of dangerous radioactive fallout particles, most of which would fall to earth during the first 24 hours. Explosions high in the air would create smaller radioactive particles, which would not have any real effect on humans until many months or years later, if at all. ”

“ Our early nuclear explosives have used fission. In the fission process a great array of radioactive products are formed, some of them intensely poisonous. More recently we have learned how to produce energy by fusion. Fusion produces fewer and very much less dangerous radioactivities. Actually the neutrons which are a by-product of the fusion reaction may be absorbed in almost any material and may again produce an assortment of radioactive nuclei. However, by placing only certain materials near the thermonuclear explosion, one may obtain a weapon in which the radioactivity is harmless. ”

“ But all these applications will use up only a vanishing 162 fraction of the fission products. Moreover, most of the biologically important elements are not produced in the fission of uranium. Many useful activities can be produced by neutron absorption in reactors. But among the fragments of uranium perhaps only radio-iodine has been put so far to direct physiological use.
Industry deals with less sensitive objects than living tissue. Therefore greater amounts of radioactive materials can be used here. And indeed radioactivity has done a great variety of jobs. ”

“ The altitude reached by the cloud depends on the force of the explosion. When yields are in the low-kiloton range, the cloud will remain in the lower atmosphere and its effects will be entirely local. But as yields exceed 30 kilotons, part of the cloud will punch into the stratosphere, which begins about 7 miles up. With yields of 2-5 megatons or more, virtually all of the cloud of radioactive debris and fine dust will climb into the stratosphere. The heavier materials reaching the lower edge of the stratosphere will soon settle out, as did the Castle/Bravo fallout at Rongelap. ”

“ Almost 90% of 112 nests built by the yellow-legged mud-dauber species were radioactive, and the mud was delivering to the wasp eggs each hour a dose of penetrating radiation equal to that received by a man from all natural sources over a period of many years. ”

“ Teena said.
“I would,” Eddie said. “Everyone is carefully protected. They see to that. Well, anyway, if all of those uranium atoms were shooting radioactive rays around inside of that pile and doing nothing, there would be an awful lot of energy going to waste. So the atomic scientists take certain elements which aren’t radioactive, but can be made radioactive, and shove small pieces of them into holes drilled in the pile.” ”

“ One of these tests involved the detonation of an atomic device under water, in the heart of the atoll’s aquatic circulatory system. Bikini also was used for 5 years, from 1954 through 1958, for the testing of thermonuclear [8] devices. Its islands and reefs were burned by atomic heat, and the waters of its lagoon were contaminated by deposits of radioactive fallout. Thus, for almost a score of years, Bikini, a small outcropping of coral in the mid-Pacific, was identified with the earliest experiments in nuclear explosion. ”

“ The work of the Curies in turn stimulated many studies of the effect of radioactivity. It was not long before experimenters learned that naturally radioactive elements—like radium—were also useful in cancer therapy. These elements emitted gamma rays, [2] which are like X rays but usually are even more penetrating, and their application often could be controlled better than X rays. Slowly, over the years, reliable methods were developed for treatment with these radioactive sources, and instruments were designed for measuring the quantity of radiation received by the patient. ”

“ All natural radioactivity in the heavy elements proceeds by such a series of steps, and the series finally ends with a stable form of lead as its end product. In other words, any naturally radioactive heavy element eventually becomes nonradioactive lead.
The nucleus of every atom (except hydrogen) contains one or more neutrons and one or more protons. The instability of the nuclei of the heavy atoms is related to the ratio of the number of neutrons to the number of protons in the nuclei. Radioactive decay is, in fact, a way of adjusting these ratios. The adjustment can occur in various ways. ”

“ If such a reactor operates for half a year and then explodes and releases its radioactive content into the atmosphere, its radioactivity will be comparable to that of a hydrogen bomb. In one important respect such an accident would be worse than a hydrogen explosion. The nuclear explosive lifts most of its radioactive products to a high altitude and the poisonous activity gets dispersed and diluted before it descends. The activity from a reactor on the other hand will remain close to the ground and might endanger the lives of the people in an area of hundreds of square miles. ”

“ If the Podkamennaya Tunguska meteorite was contraterrene, then the soil in the impact area must have been made radioactive in the same way that the earth around the “ground zero” of a nuclear explosion is contaminated by radioactivity. After the senior author had repeatedly urged Russian scientists (who are the only ones that have been permitted to visit the site of the Podkamennaya Tunguska fall) to try to detect any long-lasting radioactivities that might still be present in the ground at Podkamennaya Tunguska, such a radioactivity survey was finally carried out in the summer of 1960. ”

“ Container radioactivity has no bearing on the food, it is safe to use. The radioactivity is not transferred to the contents. No significant toxic by-products are formed in the exposed canned food. (2) Consumption of food contaminated with radioactive fallout may cause a risk of radiation injuries from internal radiation; that is, radiation from radioactive sources within the body. Most isotopes will pass through the digestive tract or be excreted very quickly. However, the intestinal tract may receive a considerable dose. ”

“ The reason mankind had remained unaware of radioactivity and very aware of chemical reactions was, first, that the most common radioactive processes are so slow that their great energies were stretched over such enormous blocks of time as to be insignificant on a per second basis. ”

“ With the passage of time the linear features would probably
develop; the energetic substratum continually asserting its
influence along such lines of weakness. It is in the highest
degree probable that radioactivity plays no less a part in
Martian history than in terrestrial. The fact of radioactive
heating allows us to assume the thin surface crust and continued
sub-crustal energy throughout the entire period of the planet's
history. ”

“ This property of nuclei to decay by themselves is called radioactivity. Radioactive nuclei decay at constant rates regardless of temperature, pressure, chemical combination, or physical state. The process goes on no matter what happens to the atom. In other words, the activity inside the nucleus is in no way affected by what happens to the ELECTRONS circling around it. (Only in very special cases can outside disturbances affect the radioactivity of a nucleus and then only slightly. For all practical purposes, rates of radioactive decay are constant.) ”