Short-lived radioactivities

As was mentioned in Chapter 3, a number of decay products of dead, short-lived 

These could come from a variety of sources including  

2 This production ratio, after Goriely and Arnould (2001), is somewhat larger than the figures in Table 10.2, which would have led to a somewhat shorter age. 

2 Short-lived activities and Galactic chemical evolution 

For a sufficiently short-lived activity (A,A 1), Eqs. (10.15) and (10.22) both lead to 

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The direct analysis of short-lived radioactive isotopes using the method outlined in Example 13.6 is less useful since it provides only a transient measure of the isotope s concentration. The concentration of the isotope at a particular moment... 

Element 86, the final member of the group, is a short-lived, radioactive element, formerly known as radium-emanation or niton or, depending on which radioactive series it originates in (i.e. which isotope) as radon, thoron, or actinon. It was first isolated and studied in 1902 by E. Rutherford and F. Soddy and is now universally known as radon (from radium and the termination-on adopted for the noble gases Latin radius, ray). 

Capaldi G, Cortini M, Gasparini P, Pece R (1976) Short lived radioactive diseqttihbria in freshly erupted volcanic rocks and their implications for the pre-emption history of a magma. J Geophys Res 81 350-... 

Radon in indoor air arises primarily from radium in the soil. The radon in the soil gas flows under a pressure gradient from the soil into the building. In some cases building practices can lead to high radon levels in the living areas of the house. Radon is chemically quite inert and does not pose a significant radiation health hazard in itself because the retained fraction in the body is so low (Mays et al., 1958). It is, however, an excellent vehicle for the dispersion of its short-lived radioactive decay products. 

K with 40Ca. Some implications of long- and short-lived radioactivities for the chronology of the Solar System will be discussed in Chapter 10. 

For more detailed discussions of isotopic anomalies and short-lived radioactivities in the Solar System, see... 

Water containing a short-lived radioactive species flows continuously through a well-mixed holdup tank. This gives time for the radioactive material to decay into harmless waste. As it now operates, the activity of the exit stream is 1/7 of the feed stream. This is not bad, but we d like to lower it still more. 

This method is used mainly for short-lived radioactive nuclides produced by cosmic ray spallation, such as °Be, A1, Si, C1, and Ar (Table 5-1). Because these nuclides have relatively short half-lives, if there was any initial amount of the nuclides at the beginning of Earth history, the initial amount would have completely decayed away. The small amount that can be found in... 

M. Haaparanta, T. Gronroos, O. Eskola, J. Bergman, O. Solin, Planar chromatographic analysis and quantification of short-lived radioactive metabolites from microdialysis fractions, J. Chromatogr. A 1108 (2006) 136-139. 

All the naturally occurring stable elements were known by the mid-twentieth century, and experiments with nuclear energy at that time brought to light a whole pantheon of heavier, short-lived radioactive elements. But only with the development of new ultrasensitive techniques of chemical analysis have we become alerted to the complexity with which they are blended in the world, seasoning the oceans and the air with exquisite delicacy. 

There are several lines of evidence that nucleosynthesis takes place in stars. The compositions of the outer envelopes of evolved low- and intermediate-mass stars show enhancements of the products of nuclear reactions (hydrogen and helium burning and s-process nucleosynthesis, as defined below). The ejecta of supemovae (stellar explosions) are highly enriched in short-lived radioactive nuclides that can only have been produced either just before or during the explosion. At the other extreme, low-mass stars in globular clusters, which apparently formed shortly after the universe formed, are deficient in metals (elements heavier than hydrogen and helium) because they formed before heavy elements were synthesized. 

Another example is provided by the chemical fractionation of tungsten into planetary cores. Tungsten has a short-lived radioactive isotope, W, which decays into Hf. Tungsten is siderophile and hafnium is lithophile. Consequently, the daughter isotope, 182Hf, will be found either in the core or the mantle depending on how quickly metal fractionation (core formation) occurred relative to the rate of decay. The Hf- W system is used to date core formation on planetary bodies. We will discuss the details of using radioactive isotopes as chronometers in Chapters 8 and 9. 

Although additional work clearly is required to sort out the details, it seems likely that a supernova was involved in the formation of the solar system and that the Sun originated in a region of cluster star formation. One avenue of future work will be to investigate the potential contributions to stable isotopes from a late supernova. It is difficult to establish the level of such a contribution from observations because there are no labels on the atoms of stable isotopes produced in the last supernova as there are for the short-lived radioactive isotopes. It might be possible to infer the contribution by comparing solar system... 

The halogens will be restricted to chlorine, bromine and iodine since fluorine, as the most electronegative element, does not function as the central atom in a complex and astatine has only short-lived, radioactive isotopes, so that very little of its coordination chemistry has been investigated.2 ... 

Figures 8.1 and 8.2 show the short-lived radioactive decay chains for 226Ra and 228Ra, respectively, to illustrate the relationship of the progeny to the two radium isotopes. Long-lived radionuclides continue both the chains.

C. J. Clark and P. D. Buckingham, in Short Lived Radioactive Gases for Clinical Use Butterworths, London, p. 237 (1975). 

Fast chemical isolation procedures to study the chemical and physical properties of short-lived radioactive nuclides have a long tradition and were applied as early as 1900 by E. Rutherford [1] to determine the half-life of 22oRn. A rapid development of fast chemical separation techniques [2,3,4,5,6,7, and Ref. 8 for an in-depth review] occurred with the discovery... 

Thus, the deposition temperature and the thermodynamic state function of the adsorption are combined and they can easily be determined from each other. The retention time for a short-lived radioactive species is calculated as the radioactive lifetime of the nuclide ... 

Another isotopic manifestation is the so-called Cosmogenic Radioactivity which is produced in meteorites owing to reactions of their stable atoms with the cosmic rays that bombard the meteorites. Owing to this, meteorites have many live short-lived radioactivities within them when they fall to ground, and measuring their amounts determines when the meteorite fell and how deep within it was the location of the sample prior to the collision that released it into space (see Extinct radioactivity and Meteorites). 

All the NPPs have their own systems for managing the solid and liquid radioactive waste generated at the site. The very low level waste (VLLW) and the low and intermediate level short lived radioactive waste (L IL SL) waste is eonditioned in accordance with the waste acceptance criteria for the landfill type and the SFR repository respectively. Standard techniques are used processing liquid and solid waste. Cement and bitumen are used as matrix for conditioning. 

SFR - Final repository for low and intermediate level short lived radioactive waste... 

To prevent such release, oft gases are treated in Charcoal Delay Systems, which delay the release of xenon and krypton, and other radioactive gases, such as iodine and methyl iodide, until sufficient time has elapsed for the short-lived radioactivity to decay. The delay time is increased by increasing the mass of adsorbent and by lowering the temperature and humidity for a boiling water reactor (BWR), a typical system containing 211 of activated carbon operated at 255 K, at 500 K dewpoint, and 101 kPa (15 psia) would provide about 42 days holdup for xenon and 1.8 days holdup for krypton (88). Humidity reduction is typically provided by a combination of a cooler-condenser and a molecular sieve adsorbent bed. 

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