Study on the preparation of a137Cs/137mBa radionuclide generator

^137mBa has been applied successfully to dynamic studies for diagnosis in nuclear medicine for a long time. A variety of inorganic exchangers have been employed for the separation of^137mBa from its parent¹³⁷Cs. In the present study, cupric cobaltic ferrocyanide and amorphous zirconyl phosphate were synthesized and compared for use in a¹³⁷Cs/^137mBa generator. The results show that the former can adsorb¹³⁷Cs more efficiently and provide high elution yield of^137mBa with greater than 99.99% radionuclide purity. A new generator involving multimillicuries of^137mBa, in connection with a computerized detection system, has been constructed.     

Rapid determination of 137Cs in environmental samples--purification of 137Cs by ammonium molybdophosphate column separation]

A rapid method for the determination of 137Cs in environmental samples was proposed. The principal technic employed in this study is based on column separation of 137Cs using ammonium molybdophosphate mixed with glass fiber to eliminate contribution of natural radionuclides such as 40K and 87Rb. The separation of cesium from potassium and rubidium was performed by the elution with 0.5m ammonium nitrate solution. The time required for separation of cesium was five hours as compared with the conventional cation exchange separation which required thirteen hours. The chemical yield of cesium carrier was normally more than 90 percent. The results obtained were compared with that by the conventional methods using Bio-Rex cation exchange separation and the good agreement between the two methods was obtained.     

Extraction-chromatographic separation of uranium from long-lived fission products using tributyl phosphate

Extraction-chromatographic separation of uranium from fission products was performed using undiluted tributyl phosphate sorbed on Chromosorb W as a stationary phase, and nitric acid (1: 3) as a mobile phase. Most of the fission products that contributed greatly to the radiation level of the sample passed through the column; this effected considerable decontamination. Uranium retained on the column was quantitatively recovered by elution with water.     

Separation of 137Cs from nuclear waste

Sodium zirconate is one member of a family of new inorganic ion exchange materials which have high affinity for all actinides and fission product cations except for Cs⁺. A combination of cold, tracer and high level liquid waste experiments with sodium zirconate has shown that 70–80 and 80–100% of the Cs⁺ in high level liquid waste remains in solution following batch or column equilibration, respectively. The fact that ¹³⁷Cs can be obtained in relatively pure form permits subsequent conversion directly to an insoluble radiation source. This is of prime importance in areas such as sewage sludge sterilization via γ-ray irradiation.     

Recovery of137Cs from acidic fission products solutions

A procedure for the isolation of¹³⁷Cs from acidic fission products solutions, based on the use of silica gel and zirconium phosphate ion exchangers, is presented. The¹³⁷Cs recovered by the ion-exchange process is converted to powder by coprecipitation of cesium with ammonium molybdophosphate.¹³⁷Cs pellets have been prepared by compression of¹³⁷Cs ammonium molybdophosphate powder using a hydraulic press. An important aspect of this procedure is that it does not require neutralization of the Purex waste.     

Fallout 137Cs in soils from North Western Libya

Fallout levels of ¹³⁷Cs in surface soil from North WesternLibya have been measured using gamma-ray spectrometry. The activity concentrationsof ¹³⁷Cs in soil ranged from 975 to 1720 mBq . kg ^—1 . The areal activity concentrations ranged from 1300 to 2250 mBq .m ^—2 , and were higly correlated with annual precipitation.The effective dose from external exposure to ¹³⁷Cs is found tobe 3 nSv . y ^—1 .     

Isolation of137Cs from excreta by dicarbolide of cobalt

Extraction by polyhedral complex compound of the formula H⁺ [(π-(3)-1,2-B₉C₂H₁₁)₂Co⁻] further on referred to as dicarbolide-H⁺ and its chloro-derivate H⁺[B₁₈C₄H₁₅Cl₇Co⁻] further on referred to as Cl-dicarbolide-H⁺ in nitrobenzene was used for the analysis of¹³⁷Cs in urine and faeces after internal contamination. The dependence of distribution ratio on the acidity of analysed solutions was determined. The effect of urine dilution was assessed as well as the effect of various concentrations of the extraction agents on the distribution ratio of¹³⁷Cs. The effect of phase ratio at the different concentrations of isotopic carrier was assessed, as well as the effect of potassium ions on the decrease of the distribution ratio at the extraction of¹³⁷Cs by dicarbolide-H⁺ or its chloro-derivate. The possibility of isolation of¹³⁷Cs by extraction and the isolation of¹³⁷Cs by ion-exchange absorbents and by ammonium molybdophosphate was compared. The values of distribution coefficient were determined at various concentrations of nitric acid and the isotopic carrier. The dependence of coextraction of some activated radionuclides and fission products by dicarbolide-H⁺ on the nitric acid concentration in the solute was determined. The effect of mass of contaminated faeces on the value of the distribution ratio of¹³⁷Cs by the extraction was evaluated. As a result, a suggestion was given for the rutine isolation procedure of¹³⁷Cs extraction with dicarbolide-H⁺ from the excreta contaminated by a mixture of radionuclides.     

Separation of 133Ba and 137Cs from Mixtures of 133Ba and 137Cs by Environmentally Benign PEG-Based Aqueous Biphasic System

Journal of Solution Chemistry - Thermodynamics of the protonation of chelidamic acid (4-oxo-1,4-dihydropyridine-2,6-dicarboxylic acid) was studied using potentiometry and calorimetry in...     

Application of Cu·FeHCF coated acrylic fibre for the separation of Cs isotopes in drinking water to determine fallout 137Cs

Ten fresh water samples of wells and rivers from the environment of Tarapur Maharashtra Site were analyzed to evaluate and establish the fall out level of ¹³⁷Cs activity concentration using large volume of water samples. A radiochemical separation method suitable for the analysis of large volume of water sample based on the adsorption of Cs isotopes on coated acrylic fibres was standardized. ¹³⁴Cs isotope was used for monitoring the radiochemical recovery of the analysis. Radiochemical recovery was obtained in the range of 74?C98% for a sample volume of 250?L or more. The fall out level ¹³⁷Cs concentration in river/dam water was found to be in the range of 0.205 to 0.268?mBq?L^?1. The fall out level annual effective dose through water ingestion pathway for a member of public was evaluated to be 2.27?×?10^?9?Sv.     

Modes of137Cs desorption from marine sediments by sea water

Sea water is observed to be a good desorbing agent for¹³⁷Cs from marine sediments. Investigations on the sites of¹³⁷Cs binding and their abundance by desorption over extended periods indicated that, whatever the time of contact of sorption,¹³⁷Cs has three modes of desorption: fast component with desorption half-time of 30–50 min, medium component with desorption half-time of 25–50 h and slow component with desorption half-time of 31–112 days. These are expected to be sites of ion exchange, slower exchange and trapped Cs in the clay mineral layer lattices.     

Release of137Cs from anoxic lacustrine sediment measurement and formulation

Low level measurements of¹³⁷Cx in lacustrine sediment and its pore water are possible to activity as low as 10 mBq. From this data, the flux of¹³⁷Cs through the sediment and to the bottom water can be estimated. The value of the diffusion coefficient in the pore water follows from separate radiotracer experiments.     

Extraction of137Cs by cobalt dicarbolide

The possibility of the use of chlorinated cobalt dicarbolide, H⁺C₄B₁₈H₁₅Cl₇Co⁻, it nitrobenzene for the selective extraction of¹³⁷Cs from mixtures of⁹⁵Zr−⁹⁵Nb,¹⁰⁶Ru-¹⁰⁶Rh and¹⁴⁴Ce was studied. The effect of aqueous phase acidity on the distribution ratio of Cs, Ru and Zr as well as the effect of the amount of isotopic and non-isotopic carriers of alkali metals on the distribution ratio were determined. Separation factors for cesium from ruthenium, zirconium and cerium were calculated, all being extracted from nitric acid solutions. The efficiency of cesium separation was verified by gamma-spectrometry.     

Retention of137Cs by algal polysaccharides

The retention of¹³⁷Cs in algal polysaccharides has been studied. Alginic acid showed higher retention value than the tested alginate samples. The retention of¹³⁷Cs in carrageen types and agar was first investigated. The binding capacities were found to be equal for carrageenan types and agar.     

Leaching behavior of137Cs in cement

To assess the safety of disposal of a radioactive waste-cement composite, the leaching of¹³⁷Cs from a waste composite into a surrounding fluid has been studied. Leaching tests were carried out in accordance with a method recommended by IAEA.¹ The leachability was measured as a function of bentonite clay to cement ratio. The fraction of¹³⁷-Cs leached from a specimen of Portland cement is 0.03–0.13 at a leaching time of 400 d. Results presented in this paper are examples of data obtained in a 10 y mortar and concrete testing project, which will influence the design of the engineered trench system for a future Yugoslav radioactive waste storage center.^2,3     

Adsorption of 137Cs on titanate nanostructures

Various types of sodium and potassium titanate nanostructures (nanotubes, nanofibers, nanoribbons, nanwires) were synthesized and characterized by X-ray diffraction, SEM and TEM, as well BET and BJH methods. Adsorption of radiotracer ¹³⁷Cs⁺ ions from aqueous solutions on synthesized titanate nanostructures was investigated in batch technique as a function of contact time, concentration of sodium ions and pH of the solutions. It was found that among the studied nanostructures nanotubes shows the highest selectivity for ¹³⁷Cs, which is related to a zeolitic character of Cs⁺ adsorption. The efficient adsorption of ¹³⁷Cs was obtained in Na⁺ solutions with concentration below 10^?2 M, at pH 7–9 and in contact time above 2 h. Moreover, nanotubes have the higher specific surface area than other nanostructures, which results in better availability of ion exchange groups and high ion exchange capacity. These properties of nanotubes indicate that they may be used for adsorption of ¹³⁷Cs from various types of nuclear wastes.     

Comparative interpretation of leaching137Cs from radwaste sludge immobilized in cement

This paper presents results from studies made to determine the leachability of¹³⁷Cs from immobilized evaporator sludge from a Pressurized Water Reactor with cement. Leaching of¹³⁷Cs from cement matrix using three methods based on theoretical equations has been developed. These were: Method I, diffusion equation derived for a plane source model, Method II, rate equation for diffusion coupled with a first-order reaction. The leaching data were also analyzed by an empirical method employing a polynomial equation —Method III. Results presented in this paper are examples of data obtained in a cement testing project which will influence the design of a future radioactive waste storage center.     

Composite cellulose-inorganic sorbents for 137Cs recovery

In this study, cellulose-inorganic sorbents based on bleached cotton fibres and ferrocyanides of different d-metals have been prepared and used for separation of ¹³⁷Cs from simulated aqueous solutions. Comparative analysis has been carried out of the sorption properties of obtained sorption materials towards to micro- and macroquantities of caesium at different liquid to solid phases ratios. Various characterization methods including X-ray analysis, IR spectroscopy, and differential thermal analysis were used to determine the structural properties of the obtained composite sorbents. It has been confirmed that the sorbents obtained at approximately the same content of the inorganic component are characterized by different values of the recovery rate and ¹³⁷Cs distribution coefficient.     

The biological half-life of137Cs in snails

The biological half-life of¹³⁷Cs in snails Helix pomatia after a single administration of contaminated diet has been investigated. The calculation was based on the retention of¹³⁷Cs in snails in vivo. It was found that loss of cesium from snails can be explained by a two-exponential retention curve leading to biological loss constants _{B 1}=0.27 d^–1 and _{B 2}=0.024 d^–1, which correspond to biological half-lives of T_{B 1}=2.5 d and T_{B 2}=28.5 d respectively. The equation describing the retention of¹³⁷Cs in snails is also presented.