Successive radioactive decay

Case (i) Successive radioactive decay. This occurs after formation of the first radioactive (parent) member Xj. Thus we only consider the left vertical chain, and assume a2, etc. = 0. In this A + I chain the second index is constant, and we omit it for case (i). This case is valid for all natural decay chains and for fission product decay chains. Each member of the decay chain can be described by the differential equation... 

One nuclear reaction is not always enough to produce a stable nuclide. A decay series is a series of radioactive nuclides produced by successive radioactive decay until a stable nuclide is reached. The heaviest nuclide of each decay series is called the parent nuclide. The nuclides produced by the decay of the parent nuclides are called daughter nuclides. All naturally occurring nuclides with atomic numbers greater than 83 are radioactive and belong to one of three natmal decay series. 

Decay Product, Daughter Product, Progeny—A new nuclide formed as a result of radioactive decay. A nuclide resulting from the radioactive transformation of a radionuclide, formed either directly or as the result of successive transformations in a radioactive series. A decay product (daughter product or progeny) may be either radioactive or stable. 

The planets nearest the Sun have a high-temperature surface while those further away have a low temperature. The temperature depends on the closeness to the Sun, but it also depends on the chemical composition and zone structures of the individual planets and their sizes. In this respect Earth is a somewhat peculiar planet, we do not know whether it is unique or not in that its core has remained very hot, mainly due to gravitic compression and radioactive decay of some unstable isotopes, and loss of core heat has been restricted by a poorly conducting mainly oxide mantle. This heat still contributes very considerably to the overall temperature of the Earth s surface. The hot core, some of it solid, is composed of metals, mainly iron, while the mantle is largely of molten oxidic rocks until the thin surface of solid rocks of many different compositions, such as silicates, sulfides and carbonates, occurs. This is usually called the crust, below the oceans, and forms the continents of today. Water and the atmosphere are reached in further outward succession. We shall describe the relevant chemistry in more detail later here, we are concerned first with the temperature gradient from the interior to the surface (Figure 1.2). The Earth s surface, i.e. the crust, the sea and the atmosphere, is of... 

The element may be obtained from radioactive lead-210 (also, known as RaD, the lead fraction in the extraction of radium from uranium ore) by successive beta decay ... 

Attempts to isolate u stable xenon chloride have not been very successful. Two chlorides have been identified, and bolh are apparently unstable species observable as a result of trapping in a matrix. The radioactive decay of 2VI in KICI., ... 

The most general model to describe radioactive decay is the binomial distribution. For a process that has two outcomes (success or failure, decay or no decay), we can write for the distribution function P(x)... 

The constancy of the half-life for a first-order reaction is illustrated in Figure 12.7. Each successive half-life is an equal period of time in which the reactant concentration decreases by a factor of 2. We ll see in Chapter 22 that half-lives are widely used in describing radioactive decay rates. 

II >0 l time between the successive events in a Poisson distribution of particles in radioactive decay. 

Figure 7.1 Hypothetical decay of a radionuclide (N) to a stable radiogenic daughter (D y, the successive loss of atoms of N from radioactive decay are followed by proportional increase in the daughter atoms. (Modified from Faure, 1986.)...

There are indications that this method will isolate the waste until the radioactivity decays to safe levels. One reassuring indication comes from the natural fission reactor at Oklo in Gabon, Africa. Initiated about 2 billion years ago when uranium in ore deposits there formed a critical mass, the reactor produced fission and fusion products for several thousand years. Although some of these products have migrated away from the site in the intervening 2 billion years, most have stayed in place. Another indication of the possible success of... 

The laws of radioactive decay are the basis of chronology by nuclear methods. From the variation of the number of atoms with time due to radioactive decay, time differences can be calculated rather exactly. This possibility was realized quite soon after the elucidation of the natural decay series of uranium and thorium. Rutherford was the first to stress the possibility of determining the age of uranium minerals from the amount of helium formed by radioactive decay. Dating by nuclear methods is applied with great success in many fields of science, but mainly in archaeology, geology and mineralogy, and various kinds of chronometers are available. 

Decay constant Measure of the probabihty of the decay of radioactive atoms [s ] Decay series Sequence of successive decay processes Disintegration Synonym of (radioactive) decay Disintegration rate Disintegrations per unit time [s ]... 

This extremely heavy uranium isotope underwent radioactive decay, forming successively heavier transuranium elements, including isotopes of elements 99 and 100. 

---