Radioactivity nuclear fusion

It IS often stated that unclear fusion tvill produce no radioactive hazard, but this is not correct. The most likely fuels for a fusion reactor would be deuterium and radioactive tritium, which arc isotopes of hydrogen. Tritium is a gas, and in the event of a leak it could easily be released into the surrounding environment. The fusion of deuterium and tritium produces neutrons, which would also make the reactor building itself somewhat radioactive. However, the radioactivity produced in a fusion reactor would be much shorter-lived than that from a fission reactor. Although the thermonuclear weapons (that use nuclear fusion), first developed in the 1950s provided the impetus for tremendous worldwide research into nuclear fusion, the science and technology required to control a fusion reaction and develop a commercial fusion reactor are probably still decades away. 

Nuclear equation, 513 Nuclear masses, 521t Nuclear radiation. See Radioactivity Nuclear reactions biological effects, 527 equations, 513 fission, 523-526 fusion, 526-527,528 mass-energy relations, 520-523,... 

Indeed, this happens every moment in the Earth s atmosphere. The upper atmosphere is bombarded with cosmic rays fast-moving subatomic particles produced by extremely energetic astrophysical processes such as nuclear fusion in the sun. When cosmic rays hit molecules in the atmosphere, they induce nuclear reactions that spit out neutrons. Some of these neutrons react with nitrogen atoms in air, converting them into a radioactive isotope of carbon carbon-14 or radiocarbon , with eight neutrons in each nucleus. This carbon reacts with oxygen to form carbon dioxide. About one in every million million carbon atoms in atmospheric carbon dioxide is C. 

J Ju elements in the periodic table exist in unstable versions called radioisotopes (see Chapter 3 for details). These radioisotopes decay into other (usually more stable) elements in a process called radioactive decay. Because the stability of these radioisotopes depends on the composition of their nuclei, radioactivity is considered a form of nuclear chemistry. Unsurprisingly, nuclear chemistry deals with nuclei and nuclear processes. Nuclear fusion, which fuels the sun, and nuclear fission, which fuels a nuclear bomb, are examples of nuclear chemistry because they deal with the joining or splitting of atomic nuclei. In this chapter, you find out about nuclear decay, rates of decay called half-lives, and the processes of fusion and fission. 

Explain how radioactive decay has always warmed Earth from the inside and how nuclear fusion has always warmed Earth from the outside. 

I he fossil fuels currently available to us are limited. At present rates of con-X sumption, known recoverable oil and gas reserves will disappear by the end of the century and coal reserves several centuries after that. Furthermore, burning fossil fuels adds undesirable amounts of greenhouse gases to the atmosphere. Nuclear fission reactors do not emit greenhouse gases, but they generate massive quantities of radioactive wastes. Nuclear fusion reactors offer many potential benefits, but it may take many decades before they are both technologically and economically feasible. So what do we do ... 

Radioactivity -of fusion reactions [FUSION ENERGY] (Vol 12) -monitoring in nuclear reactors [NUCLEARREACTORS - SAFETY IN NUCLEAR POWER FACILITIES] (Vol 17) -ofnuclear reactor waste [NUCLEARREACTORS - WASTE MANAGEMENT] (Vol 17) -ofpotassium-40 [POTASSIUMCOMPOUNDS] (Vol 19) -role m ore sorting [MINERALS RECOVERY AND PROCESSING] (Vol 16)... 

Fusion promises to provide a nearly inexhaustible supply of hydrogen fuel as well as less radioactive waste, but temperatures of fusion reactions are too high for present materials, and the huge amounts of energy needed to start fusion reactions would explode or melt any known construction materials. The fires of nuclear fusion in our Sun provided energy for early humans long before they discovered the art of combustion, see also Chemical Reactions Chemistry and Energy Explosions Fossil Fuels. 

The gas is also used to fill balloons, in gas discharge lamps, and as an additive in the breathing gases of astronauts and scuba divers. The rarer stable isotope of helium (3He) is produced by the decay of radioactive tritium, and is used in resonance imaging and in the attainment of very low temperatures, about 0.010 kelvin, via a process known as dilution refrigeration. see also Noble Gases Nuclear Fusion. 

Nuclear fusion does not require uranium fuel and does not produce radioactive waste, and has no risk of explosive radiation-releasing accidents, but it takes place at a temperature of several million degrees. Nuclear fusion occurs in the sun, its fuel is hydrogen and, as such, it is an inexhaustible and a clean energy source. The problem with this technology is that, because it operates at several million degrees of temperature, its development is extremely expensive, and it will take at least until 2050 before the first fusion power plant can be built (Tokomak fusion test reactors). It is estimated that it will be 50 times more expensive than a regular power plant, and its safety is unpredictable. In short, the only safe and inexpensive fusion reactor is the Sun ... 

Deuterium (2D) and tritium (3T) are heavier isotopes of hydrogen. The former is stable and makes up about 0.015 per cent of all normal hydrogen. Its physical and chemical properties are slightly different from those of the light isotope Tl For example, in the electrolysis of water H is evolved faster and this allows fairly pure D2 to be prepared. Tritium is a radioactive b-emitter with a half-life of 12.35 years, and is made when some elements are bombarded with neutrons. Both isotopes are used for research purposes. They also undergo very exothermic nuclear fusion reactions, which form the basis for thermonuclear weapons (hydrogen bombs) and could possibly be used as a future energy source. 

Radioactive Isotopes Radioactive Emanations Separating Nuclear Emanations Nuclear Fusion and Fission Half-Life (t1/2)... 

Proton-proton fusion chain reactions (Bethe and Critchfield 1938) the first long-lived intermediate of nuclear fusion in low-mass stars, He, adds to one He to yield (radioactive) Be which eventually produces two He by capture of another proton and radioactive decay of B (pp-111 chain) or vice versa along the Be decay product Li -l- p (pp-11). 

The rewards of a workable nuclear fusion process would be great. Fusion produces neither the long-lived radioactive nuclides that accompany nuclear fission (although tritium requires care in handling) nor the environmental pollutants released by the burning of fossil fuels. Although deuterium is present in only 1/6000 of the abundance of ordinary hydrogen, its separation from the latter by the electrolysis of water is readily accomplished, and the oceans contain a virtually unlimited quantity of deuterium. 

Compare and contrast nuclear fission and nuclear fusion. Demonstrate equations that represent the changes that occur during radioactive decay. 

A nuclear application of lithium is in thermonuclear weapons and fusion research. In a weapon or fusion reactor, nuclear fusion occurs between two isotopes of hydrogen—deuterium and tritium. Deuterium occurs naturally and has an abundant supply in the worlds oceans (it is present in about 0.015 percent of water molecules). Tritium, on the other hand, is radioactive, has a relatively short half-life, and does not occur naturally. Tritium can be manufactured, however, by bombarding lithium 6 with neutrons. 

In contrast to the fission process, nuclear fusion looks like a very promising energy source, at least on paper. Although thermal pollution would be a problem, fusion has the following advantages (1) The fuels are cheap and almost inexhaustible and (2) the process produces little radioactive waste. If a fusion machine were turned off, it would shut down completely and instantly, without any danger of a meltdown. 

Explain why achievement of nuclear fusion in the laboratory requires a temperature of about 100 million degrees Celsius, which is much higher than that in the interior of the sun (15 million degrees Celsius). Tritium contains one proton and two neutrons. There is no proton-proton repulsion present in the nucleus. Why, then, is tritium radioactive ... 

The fact that atoms were not eternally stable became evident in the discovery of radioactivity by Becquerel, followed by the extensive investigations of nuclear transformations by Marie Curie, Rutherford, Soddy, and others. Atoms thus are not indivisible eternal building blocks, but rather entities having a life history from their birth from simpler atomic nuclei by nuclear fusion to their decay or fusion to form other atoms. Radioactive decay is the conversion in time of some atoms into others and thus makes clear the inadequacy of using the atoms now known as starting points for the construction of chemistry. 

Although Dalton s theory was founded on meager and primitive experimental information, we regard much of it as correct today. Postulates 1, 4, 5, and 6 are currently regarded as true. The discovery of the processes of nuclear fusion, fission ("splitting" of atoms), and radioactivity has disproved the postulate that atoms cannot be created or destroyed. Postulate 3, that all the atoms of a particular element are identical, was disproved by the discovery of isotopes. 

Nuclear energy, which is obtained when nucleons (protons and neutrons) are allowed to adopt lower energy arrangements and to release the excess energy as heat, does not contribute to the carbon dioxide load of the atmosphere, but it does present pollution problems of a different land radioactive waste. Optimists presume that this waste can be contained, in contrast to the burden of carbon dioxide, which spreads globally. Pessimists doubt that the waste can be contained—for thousands of years. Nuclear power depends directly on the discipline of chemistry in so far as chemical processes are used to extract and prepare the uranium fuel, to process spent fuel, and to encapsulate waste material in stable glass blocks prior to burial. Nuclear fusion, in contrast to nuclear fission, does not present such serious disposal-related problems, but it has not yet been carried out in an economic, controlled manner. 

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