15.—Natural Radioactive Decay Series Elements in the Oceans and Sediments

1972 ◽  
Vol 72 (1) ◽  
pp. 167-182 ◽  
Author(s):  
J Thomson ◽  
A. Walton
Keyword(s):  
Radioactive Decay ◽  
Decay Chain ◽  
Secular Equilibrium ◽  
Marine Geochemistry ◽  
Daughter Nuclide ◽  
Decay Products ◽  
Naturally Occurring ◽  
Decay Series ◽  
Time Required ◽  
Radio Isotopes

The parents of the three naturally occurring radioactive decay series (text-fig. 1),232Th, 238U and 235U, have existed since the time of formation of the earth and through the process of radioactive decay have continuously generated their shorterlived daughter radio-isotopes. Under conditions where these decay products are not separated from the parents the situation referred to as secular equilibrium may be attained at which the activity ratio of any two daughters in the same decay chain is unity. The time required for the attainment of this situation corresponds to several half-lives of the longest lived daughter nuclide. In a great many instances, however, secular equilibrium is not achieved. Excellent examples of disequilibrium are to be found in the distribution of natural radioactive decay series elements in the oceans and sediments. These situations can be used to advantage in marine geochemistry to obtain information on residence times of elements in the oceans and rates of sedimentation occurring under a variety of conditions.

The radioactive decay series 138Nd → 138Pr → 138Ce

1970 ◽  
Vol 48 (14) ◽  
pp. 2151-2157 ◽  
Author(s):  
James J. Hogan
Keyword(s):  
Direct Measurement ◽  
Gamma Rays ◽  
Radioactive Decay ◽  
Excited Level ◽  
Branching Ratio ◽  
Decay Chain ◽  
Decay Series

Measurements of the energies and intensities of gamma rays associated with decay of 138Nd, 138Prm, and 138Prg have been performed using a Ge(Li) detector. The branching ratio to a previously unreported excited level of 138Pr (328.1 keV) has been measured, thus allowing for direct measurement of the decay of 138Nd. Half-lives of 2.20 ± 0.07 and 5.04 ± 0.09 h have been measured for 138Prm and 138Nd, respectively. Decay schemes for 138Prm → 138Ce and for the decay chain 138Nd → 138Prg → 138Ce are proposed.

Radioisotope Fractionation and Secular Disequilibrium in Performance Assessment for Geologic Disposal of Nuclear Waste

2002 ◽  
Vol 713 ◽  
Author(s):  
William M. Murphy ◽  
David A. Pickett
Keyword(s):  
Performance Assessment ◽  
Nuclear Waste ◽  
Decay Chain ◽  
Alpha Decay ◽  
Natural System ◽  
Chemical System ◽  
Secular Equilibrium ◽  
Natural Systems ◽  
Decay Series ◽  
Geologic Disposal

ABSTRACTTwo potential applications of radioisotope fractionation and decay-series secular disequilibrium in performance assessment for geologic repositories for nuclear waste are preferential radionuclide release in source term analysis and characterization of system closure as a measure of the capacity of the geologic system to isolate waste. A primary mechanism of radioisotope fractionation is selective release and mobility of alpha decay products because of nuclear recoil effects, which is evident in natural system data. Preferential release of radioisotopes from nuclear waste forms or solubility limiting solid phases could affect repository performance; however, consequences of differential radioisotope releases are neglected in performance assessments. Decay-series disequilibria are useful also to characterize open/closedsystem behavior in natural systems. Systems that are closed on time scales that are long relative to the half-lives of decay chain nuclides achieve secular equilibrium characterized by unit activity ratios among series nuclides. For geologic disposal of nuclear waste, measures focused on chemical system closure could capture the essential characteristics of the natural system with respect to radionuclide isolation and could be based quantitatively on uranium and thorium decay series secular equilibria/disequilibria.

scholarly journals DECSERVIS: a tool for radioactive decay series visualisation

2006 ◽  
Vol 4 (4) ◽  
pp. 822-834 ◽  
Author(s):  
Saad Azzam ◽  
Juhani Suksi
Keyword(s):  
Initial Conditions ◽  
Radioactive Decay ◽  
Decay Chain ◽  
Decay Series ◽  
Closed Systems ◽  
Natural Decay ◽  
User Friendly ◽  
Interactive Visualisation ◽  
Flexible Operation ◽  
Chain Decay

AbstractWe have developed an interactive visualisation tool, decay series visualisation (DECSERVIS), for exploring the three natural radioactive decay chains. Through DECSERVIS, one can investigate the full decay scheme of any natural decay chain radionuclide to obtain the number of nuclides, their masses, activities, and activity ratios, accounting for all the daughters, starting from initial conditions freely chosen by the user. The tool has been developed particularly for user friendly and flexible operation. Chain decay in closed systems can be explored as a function of time with various graphical presentations such as solid curve and column diagrams or animation. We present several exploration examples related to geological dating. DECSERVIS will be freely available on request.

ESTIMATION OF CONCENTRATION OF RADON, THORON AND THEIR DAUGHTER PRODUCTS IN RESIDENTIAL HOUSES OF SHAHJAHANPUR AND HARDOI

2015 ◽  
Vol 3 (4) ◽  
pp. 346-349
Author(s):  
Sachin Kumar
Keyword(s):  
Oil And Gas ◽  
Lung Cancer Risk ◽  
Indoor Radon ◽  
Radioactive Decay ◽  
Decay Product ◽  
Soil Environment ◽  
Product Concentration ◽  
Naturally Occurring ◽  
Decay Series ◽  
Thoron Progeny

Uranium is a naturally occurring radioactive element present in trace amount throughout the earth's crust. Radon is a progeny of uranium decay series formed from the radioactive decay of radium in the ground water, soil, environment, oil and gas deposits. The lung cancer risk depends on the above recommendation level concentration of radon, thoron and their decay product in the air.The measurement of indoor radon and thoron decay product concentration in houses of Shahjahanpur and Hardoi have been carried out using deposition based direct radon progeny sensors (DRPS) and direct thoron progeny sensors (DTPS) technique. The concentration of radon and thoron is observed to be higher in mud houses as compared to the cemented houses.

scholarly journals Elements of Natural Radioactive Decay Series in Iranian Drinking Water and Cigarettes

2010 ◽  
Vol 61 (2) ◽  
pp. 235-239 ◽  
Author(s):  
Saeed Mohammadi
Keyword(s):  
Drinking Water ◽  
Chemical Structure ◽  
Annual Effective Dose ◽  
Radioactive Decay ◽  
Average Concentration ◽  
World Health ◽  
Naturally Occurring ◽  
Decay Series ◽  
Health Organization ◽  
Different Parts

Elements of Natural Radioactive Decay Series in Iranian Drinking Water and CigarettesThe uranium (238U) decay series provides the most important isotopes of elements radium (226Ra), radon (222Rn), and polonium (210Po) with half-lives of about 1600 years, 3.8 days, and 140 days, respectively. Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (radon) complicates its handling in the laboratory and natural environment. In this study, we used the average concentrations of naturally occurring radionuclide 226Ra in drinking water at different parts of Iran to estimate the annual effective dose. In the other part of the study, we measured the concentrations of 210Po in Iranian cigarettes to estimate the internal intake of this radionuclide and its concentration in the lung tissues of smokers. The results indicate that the average concentration of 226Ra in Iranian drinking water was below the 100 mBq L-1 recommended by the World Health Organization while the average concentration of 210Po and 210Pb in Iranian cigarettes was relatively high in comparison with other cigarettes found on the market.

scholarly journals Atmospheric Neutrinos

2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Takaaki Kajita
Keyword(s):  
Atmospheric Neutrino ◽  
Decay Chain ◽  
Muon Neutrinos ◽  
Atmospheric Neutrinos ◽  
Electron Neutrinos ◽  
Tau Neutrinos ◽  
Decay Products ◽  
Charged Pions ◽  
Neutrino Experiments ◽  
Energy Dependent

Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses atmospheric neutrino experiments and the neutrino oscillation studies with these neutrinos.

Simultaneous resolution of reactive radioactive decay, non-isothermal flow, and migration with application to the performance assessment for HLW repositories

2010 ◽  
Vol 98 (6) ◽  
Author(s):  
R. Juncosa ◽  
I. Font ◽  
J. Delgado
Keyword(s):  
Ion Exchange ◽  
Radioactive Decay ◽  
Chemical Species ◽  
High Level Waste ◽  
Chemical Components ◽  
Clay Material ◽  
Decay Series ◽  
And Migration ◽  
High Level ◽  
Radioactive Species

AbstractRadioactive decay is an important subject to take into account when studying the thermo-hydro-dynamic behavior of the buffer clay material used in the containment of radioactive waste. The modern concepts for the multibarrier design of a repository of high level waste in deep geologic formations consider that once canisters have failed, the buffer clay material must ensure the retention and/or delay of radionuclides within the time framework given in the assessment studies. Within the clay buffer, different chemical species are retarded/fixed according to several physicochemical processes (ion exchange, surface complexation, precipitation, matrix diffusion, ...) but typical approaches do not consider the eventuality that radioactive species change their chemical nature (The radioactive decay of an element takes place independently of the phase (aqueous, solid or gaseous) to which it belongs. This means that, in terms of radionuclide fixation, some geochemical processes will be effective scavengers (for instance mineral precipitation of crystal growth) while others will not (for instance ion exchange and/or sorption).In this contribution we present a reactive radioactive decay model of any number of chemical components including those that belong to decay series. The model, which is named FLOW-DECAY, also takes into account flow and isotopic migration and it has been applied considering a hypothetical model scenario provided by the project ENRESA 2000 and direct comparison with the results generated by the probabilistic code GoldSim. Results indicate that FLOW-DECAY may simulate the decay processes in a similar way that GoldSim, being the differences related to factors associated to code architecture.

scholarly journals Radiogeological Assessment of Candidate Sites For Nuclear Waste Repositories, Exemplified by Studies of The Stripa Pluton, Sweden

1981 ◽  
Vol 6 ◽  
Author(s):  
H. A. Wollenberg ◽  
S. Flexser ◽  
L. Andersson
Keyword(s):  
Nuclear Waste ◽  
Radioactive Decay ◽  
Apparent Size ◽  
Geothermal Heat ◽  
Flow Paths ◽  
Naturally Occurring ◽  
Groundwater Systems ◽  
Natural Tracer ◽  
Waste Repositories ◽  
Potassium 40

ABSTRACTInvestigation of candidate sites for nuclear waste isolation will require an assessment of their radiogeologic settings. Studies at the Stripa research facility in granitic rock of central Sweden incorporated the distribution and abundance of naturally occurring radioelements in rocks encompassing the underground experiments and in the accompanying fracture-controlled groundwater system. These studies showed that besides defining the natural radioactivity baseline upon which the effects of radioactive waste will be superimposed, radioelement distributions can be used to determine the apparent age of the groundwater and its flow paths. In crystalline rocks, where the groundwater systems are confined to the joints and fractures, the uranium daughter element, radon-222 in the water serves as a natural tracer to locate fractures along which significant flow is occurring and to measure the flow rates. The heat production from radioactive decay of uranium-238, thorium-232 and potassium-40 in the rock, combined with measurements of regional and local geothermal heat flow, permit calculation of the apparent size of the rock mass that will encompass the repository. This method is especially useful in terranes such as at Stripa where the contacts between plutons and older rocks are concealed.

scholarly journals Radon content in Danish till deposits: relationship with redox conditions and age

1969 ◽  
Vol 20 ◽  
pp. 39-42
Author(s):  
Peter Gravesen ◽  
Peter Roll Jakobsen
Keyword(s):  
Water Content ◽  
Clay Minerals ◽  
Organic Material ◽  
Half Life ◽  
Radioactive Decay ◽  
Decay Chain ◽  
Redox Conditions ◽  
Transport Rate ◽  
Radon Content

Radon (222Rn) is a radioactive, noble insoluble gas with a half-life of 3.8 days. It belongs to the uranium (238U) decay chain where radon is formed from radium (226Ra). Uranium and radium are built into mineral structures or are, for example, adsorbed on the surface of clay minerals, limonite or organic material. When radon is formed by radioactive decay from radium, parts of it enter the pores of rocks and soils and are transported by diffusive or advective forces in the pores. The transport rate depends on the permeability and water content in the pores (Nazaroff 1992).

Sign in / Sign up

Export Citation Format

Share Document