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Abstract  

Proficiency testing is one of methods for regularly assessing the accuracy of the analytical data produced by laboratories for particular measurements. In 2008 and 2010, we participated in the IAEA 2008 and 2010 worldwide open proficiency tests on the determination of natural radionuclides in water spiked with 226Ra, 234U and 238U for activity analysis and with 90Sr and 230Th for gross alpha/beta analysis. Feedback statistics from the IAEA final report showed that the radioactivities of all of the samples fell within an acceptable range according to the IAEA. For 226Ra analysis, our result showed that 229Th–225Ra is suitable as a chemical tracer, although there are doubts that different co-precipitation efficient between parent 229Th and its daughter nuclide 225Ra in published literature. The impact factors of the analysis results, such as the lower limit of detection, standard substances, the background and efficiency for daily determination, are discussed in detail.

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Abstract  

The234U and230Th radionuclides are highly retarded by factors of 104 to 105 in basalt groundwater (Hanford) and briny groundwaters from Texas, and geothermal brine from the Salton Sea Geothermal Field (SSGF). In basalt groundwaters (low ionic strength), Ra is highly sorbed, while in brines (high ionic strength), Ra is soluble. This is probably because the sorption sites are saturated with Na+ and Cl ions, and RaCl2 is soluble in brines.210Pb is soluble in SSGF brine, probably as a chloride complex. The234U/230Th ratios in basalt groundwaters and brines from Texas and SSGF are nearly unity, indicating that U is in the +4 state, suggesting a reducing environment for these aquifers.

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Abstract  

As part of Canada’s international commitment for the collective defence of allied nations, nuclear submarines from allied nations berth at three approved locations on both east and west coasts of Canada. In the case of any untoward event, a nuclear emergency response (NER) organisation has been established. In addition, regular sampling of the coastal environment is undertaken as the Environmental Radionuclide Monitoring Programme (ERMP). This continuing effort consists of a long-term programme and a visit sub-programme. In the former, samples are ocean sediment, seawater, aquatic plants and sealife; in the latter, samples are seawater taken before, during and after each visit. Samples are collected according to a prescribed schedule and follow a chain of custody to the accredited laboratory in the SLOWPOKE-2 Facility at RMC. Counting and analyses are done by gamma-ray spectroscopy by the Analytical Services Group (ASG) at RMC. With most results below detection limit, the safety of the NPV visits is assured.

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Electromigration of carrier-free radionuclides

XIV. Complex formation of241Am-Am(III) with oxalate and sulfate in aqueous solution

Journal of Radioanalytical and Nuclear Chemistry
Authors: F. Rösch, T. Reimann, V. Buklanov, M. Milanov, V. Khalkin, and R. Dreyer

Abstract  

Using a special type of on-line electromigration measurements of -emitting radio-nuclides in homogeneous aqueous electrolytes free of supporting material, complex formation of carrier-free241Am-Am(III) has been studied in perchlorate electrolytes, T=298.1 (1) K. Stoichiometric stability constants for oxalate ligand of log K1=5.01 (13), 5.11 (13) and 5.38 (18) as well as log K2=3.15 (15), 3.19 (14) and 3.58 (26) were obtained at the overall ionic strength of =0.10, 0.05 and 0.01, respectively. The corresponding thermodynamic stability constants are log K 1 0 =5.90 (15) and log K 2 0 =3.73 (18). The sulfate ligand values of log K1=2.5 (2) were obtained both in acidic and neutral solutions, =0.10.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: A. Awudu, A. Faanu, E. Darko, G. Emi-Reynolds, O. Adukpo, D. Kpeglo, F. Otoo, H. Lawluvi, R. Kpodzro, I. Ali, M. Obeng, and B. Agyeman

Abstract  

Knowledge of radioactivity levels in human diet is of particular concern for the estimation of possible radiological hazards to human health. However, very few surveys of radioactivity in food have been conducted in Ghana. The natural radionuclides 226Ra, 228Ra, 228Th and 40K were measured in the foodstuffs using gamma ray spectrometry. All samples were found to contain high 40K content in the range 87.77–368.50 Bq kg−1. The maximum concentration of 228Th and 40K were found in cassava to be 14.93 ± 3.86 and 368.50 ± 19.20 Bq kg−1, respectively. The total annual committed effective dose was estimated to be 4.64 mSv. The daily intake of radionuclides from food consumption reveals that cassava and plantain are the highest contributors, while millet is the lowest. The daily radionuclide intake from the foodstuffs consumed by the general public was 411.32 Bq and the daily internal dose resulting from ingestion of the radionuclides in the foodstuffs was 0.01 mSv. The radionuclide concentrations were comparable with those reported from other countries.

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Abstract  

A deep geologic disposal is the prime option for the long-term isolation of high-level radioactive waste (HLW) in many countries. For deeply located repositories, a radionuclide released from a failed waste container moves through the engineered and natural barriers before it reaches a biosphere. The pseudo-colloid which a radionuclide is adsorbed on a moving natural humic or fulvic colloid can be generated in a fractured porous medium. The size of a colloid is in general in the order of a hundred nanometer so that its migration velocity in a fracture is higher than that of a radionuclide due to the hydrochromatic effect. A large colloid cannot diffuse easily into a surrounding rock. Also, there are many kinds of actinides and these actinides have decay chains. In this analysis, the canonical form solution is derived for a pseudo-colloid and a solute in a fracture and a surrounding rock with a realistic inlet boundary condition with multi-member decay chains. It is used the Fortran based a computational code which uses a special subroutine for the inversion of Laplace transform. Consequently, the role of the pseudo-colloid in the fractured porous medium is important and also their decay chains aren’t neglected in the performance assessment of the HLW.

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. R. (1989): Comparison of left ventricular ejection fractions determined in healthy anesthetized dogs by echocardiography and gated equilibrium radionuclide ventriculography. Am. J. Vet. Res. 11, 1840-1847. Comparison of left

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Journal of Radioanalytical and Nuclear Chemistry
Authors: D. Robertson, A. Schilk, K. Abel, E. Lepel, C. Thomas, S. Pratt, E. Cooper, P. Hartwig, and R. Killey

Abstract  

In order to more accurately predict the rates and mechanisms of radionuclide migration from lowlevel waste disposal facilities via groundwater transport, ongoing studies are being conducted at field sites at Chalk River Laboratories to identify and characterize the chemical speciation of mobile, long-lived radionuclides migrating in groundwaters. Large-volume water sampling techniques are being utilized to separate and concentrate radionuclides into particulate, cationic, anionic, and nonionic chemical forms. Most radionuclides are migrating as soluble, anionic species which appear to be predominately organoradionuclide complexes. Laboratory studies utilizing anion exchange chromatography have separated several anionically complexed radionuclides, e.g.,60Co and106Ru, into a number of specific compounds or groups of compounds. Large-volume ultra-filtration experiments have shown that significant fractions of the radionuclides are being transported in these groundwaters in the form of macromolecules having molecular weights ranging from less than 3,000 to 100,000.

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Abstract  

The radionuclide purity of medical (99mTc) and technical (60Co,109Cd) products was determined by γ-spectrometry. The impurities found allowed in all cases to draw conclusions on the method of production. The importance of radionuclide purity control is demonstrated.

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Abstract  

The trend of variation of sediment radiocontamination, expressed as a function of space and time, and specific accumulation of particular radionuclides in some investigated localities, are discussed on the basis of experimental results of gamma spectrometric analyses of artificial radionuclide contents.

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