Krypton concentration atmosphere

Krypton was discovered by William Ramsay and M.W. Travers in 1898. The element was named krypton, after the Greek word kryptos which means hidden. Krypton in trace quantities is found in the earth s atmosphere at a concentration level of about 1.14 ppm. The gas also is found in the spent fuel from nuclear reactors, resulting from fission of uranium and plutonium nuclei. Krypton has been found in Mars atmosphere in trace concentration. 

In contrast to the terrestrial planets, the giant planets are massive enough to have captured and retained nebular gases directly. However, concentrations of argon, krypton, and xenon measured in Jupiter s atmosphere by the Galileo spacecraft are 2.5 times solar, which may imply that its atmosphere preferentially lost hydrogen and helium over the age of the solar system. 

Helium is the second most abundant element in the universe. In the Earth, it is continuously formed by radioactive decay, mostly of uranium and thorium. Its present concentration in the atmosphere is probably the equilibrium concentration between the amount being released from the Earth s crust and the amount of hehum escaping from the atmosphere into space. The atmosphere represents the major source for neon, argon, krypton, and xenon. They are produced as by-products during flactional distillation of liquid air. Radon is obtained from the radioactive decay of radium. 

Krypton is produced in nuclear fi ssion, and its atmospheric abundance is a measure of worldwide nuclear activity. Krypton is found in the atmosphere with a concentration of about 1 ppm. 

Krypton (from the Greek word kryptos, meaning hidden ), is the second heaviest of the nohle gases. It was discovered in 1898 by Sir William Ramsay and Morris Travers dining their experiments with bquid air, air that has been bquefied by coobng. It has a concentration of 1.14 ppm by volume in Earth s atmosphere. It is present in the Sun and in the atmosphere of Mars. 

Concentration and Recovery of Krypton Kr-85 has a half-life of the radioactive decay of 10.7 yr and is produced by both natural and man-made sources. The natural sources include the interaction of cosmic rays with stable isotopes of Kr in the atmosphere. The man-made Kr-85 is principally produced during the fission reactions in LWR or during nuclear atmospheric tests it is also released from nuclear-fuel reprocessing activities. Due to its atmophile nature, most Kr (>98%) resides in the atmosphere and becomes isoto-pically well mixed within a few years (Yokochi, ITeraty, and Sturchio, 2008). There are no... 

For a few decades, Kr-85 artificial production shows a continuous increase of its average volumic activity into the atmosphere. In the North hemisphere, the atmospheric concentration was of 0.1 Bq m" in 1959, 0.8 Bq m" in 1980, and 1.2 Bq m in 2001 (Berard et al., 2001). One cannot say that the removal of tritium and krypton from gaseous waste is an immediate waste management requirement, but it may become one in the future (Lennemann et al., 1975). Opinions differ as to the need to isolate Kr-85. Thus, Geary (1988) states that dispersal is almost certainly preferable to disposal, based on the relatively low inventories and hazards involved. Mellinger (1985) suggested that the population risks arising from the routine release of Kr-85 would not exceed the occupational risk associated... 

Figure 7.51. activity concentrations in the TMI-2 containment atmosphere during and after krypton venting (Cline et al., 1981)... 

Krypton, neon, and xenon are rare atmospheric gases. Each is odorless, colorless, tasteless, nontoxic, monatomic, and chemically inert. All three together constitute less than 0.002 percent of the atmosphere with approximate concentrations in the atmosphere of 18 ppm for neon, 1.1 ppm for krypton, and 0.09 ppm for xenon. Few users of the three gases need them in bulk quantities, and the three are shipped most often in single cylinders and glass liter flasks. 

Krypton and xenon, which have a concentration of 1.138 ppm and 0.086 ppm in the atmospheric air, are mainly recovered as secondary products from air separation. The worldwide demand increases annually. In 2001, the global annual Xe-produc-tion amounted to about 6800 m, the Kr-production to about 67 000 m. Owing to its low concentration in the air the xenon price is high with typical 4000-8000 per m and is strongly fluctuating. The price for krypton, which occurs about 13 times more frequently in the air than xenon, is lower by about this factor. Typically the noble gases Kr and Xe are recovered in two steps ... 

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