Radionuclides distribution processes

Londhe, V.S. and Rao, S.R., Study of distribution of some neutral radionuclides on processing of rock phosphate. Bull. Radiat. Prot. 11 (1988) 181-186. 

The control technique of fuel distribution in uranium - graphite fiael elements seems to be most perform. The technique allows to determine weight of uranium or its connections in a chosen zone of fuel elements. There were used the sources of radiation on a basis radionuclide Am. The weight of uranium in fuel element or its parts is determined by combine processing of a tomograms, set received on several parallel layers of fuel element. The comparative results of tomographic researches and chemical analysis of weight of uranium in quarters of spherical fuel elements are resulted in the table. 

For a radionuclide to be an effective oceanic tracer, various criteria that link the tracer to a specihc process or element must be met. Foremost, the environmental behavior of the tracer must closely match that of the target constituent. Particle affinity, or the scavenging capability of a radionuclide to an organic or inorganic surface site i.e. distribution coefficient, Kf, is one such vital characteristic. The half-life of a tracer is another characteristic that must also coincide well with the timescale of interest. This section provides a brief review of the role of various surface sites in relation to chemical scavenging and tracer applications. 

In this article we plan to focus on two aspects (i) the transport of radionuclides to the ocean floor and the processes which govern their distribution in deep-sea sediments and (ii) the application of deep-sea sediments to retrieve historical records of large scale phenomena, e.g. long term changes in the rate of production of nuclides by cosmic rays. Even while discussing these aspects, our emphasis will be mainly on the processes rather than on the details of the chronometric method. 

Once the radionuclides reach the sediments they are subject to several processes, prime among them being sedimentation, mixing, radioactive decay and production, and chemical diagenesis. This makes the distribution profiles of radionuclides observed in the sediment column a residuum of these multiple processes, rather than a reflection of their delivery pattern to the ocean floor. Therefore, the application of these nuclides as chrono-metric tracers of sedimentary processes requires a knowledge of the processes affecting their distribution and their relationship with time. Mathematical models describing some of these processes and their effects on the radionuclide profiles have been reviewed recently [8,9,10] and hence are not discussed in detail here. However, for the sake of completeness they are presented briefly below. 

Radioactive substances (radionuclides) are known health hazards that emit energetic waves and/or particles that can cause both carcinogenic and noncarcinogenic health effects. Radionuclides pose unique threats to source water supplies and chemical processing, storage, or distribution systems because radiation emitted from radionuclides in chemical or industrial waste systems can affect individuals through several pathways by direct contact with, ingestion or inhalation of, or external exposure to, the contaminated waste stream. While radiation can occur naturally in some cases due to the decay of some minerals, intentional and nonintentional releases of... 

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