Diffusion of actinides in glasses containing simulated radioactive wastes

Diffusion coefficients of radionuclides²³⁷Np,²³⁹Pu and²⁴¹Am in simulated alumina phosphate and alumina borosilicate glasses at temperatures lower than their transformation temperature were determined. Actinides are known to be the least mobile elements. In particular, the diffusion coefficients of actinides in alumina phosphate glasses at 673 K are about 10^–18 m²·s^–1, and in alumina borosilicate at 773 K about 10^–19 m²·s^–1. It is shown that crystallization of glasses leads to increasing²³⁷Np diffusion mobility. It is also shown that a rather small quantity of water absorbed by a crystallized alumina phosphate glass in tensifies low-temperature migration of²³⁷Np.     

Treatment of wastes containing cesium ions by electrochemical ion-exchange (EIX)

In this study, an electrochemical ion-exchange (EIX) technique, based on cationic resin and zirconium phosphate (ZrP), have been chosen for the separation of cesium from radioactive wastes. These materials show high chemical stability in oxidizing media and under ionizing radiation. Charcoal, graphite and binder used in the formulation of electrodes have been studied as well. 99.8% of the cesium sorption from solution was observed. The great advantage of this process is the total release of cesium at room temperature, by reversing polarities, which makes possible the reuse of the electrode without losing its exchanging capacity.     

Substantiation of a technology for surface reclamation of tailings dump containing toxic wastes

An innovative technology has been substantiated for the environmental rehabilitation of areas subject to adverse anthropogenic impacts during the past century. The up-to-date state of the anthropogenic system generated as a result of the activity of former Khrustal’nensky ore-dressing plant has been estimated. Characteristics of anthropogenic pollution have been determined, and principles and concepts have been developed for ensuring environmental safety of tailings dump via reclamation of its surface.     

Utilization of agro-resources by radiation treatment -production of animal feed and mushroom from oil palm wastes

The production of animal feeds and mushrooms from oil palm cellulosic wasres by radiation and fermentation has been investigated in order to utilize the agro-resources and to reduce the smoke pollution. The process is as follows: decontamination of microorganisms in fermentation media of empty fruit bunch of oil palm (EFB) by irradiation, inoculation of useful fungi, and subsequently production of proteins and edible mushrooms. The dose of 25 kGy was required for the sterilization of contaminating bacteria whereas the dose of 10 kGy was enough to eliminate the fungi. Among many kinds of fungi tested, C. cinereus and P. sajor-caju were selected as the most suitable microorganism for the fermentation of EFB. The protein content of the product increased to 13 % and the crude fiber content decreased to 20% after 30 days of incubation with C. cinereus at 30°C in solid state fermentation. P. sajor-caju was suitable for the mushroom production on EFB with rice bran.     

Producing radioisotopes in power reactors

The demand of radioisotopes is rising due to wide-ranging applications in industry, agriculture, medicine and in research. Two sources of artificial radioisotopes are accelerators and reactors. The reactor offers large volume for irradiation, simultaneous irradiation of different samples and economy of production, whereas accelerators are generally used to produce those isotopes which can not be produced by reactor. Radioisotope production started on a significant scale in several countries with the commissioning of research reactors starting from the late 1950s. The period from 1950 to 1970 saw construction of a large number of research reactors with multiple facilities. After 1980, because of the decommissioning of many old ones, the number of operating reactors has been steadily decreasing. The research reactors used for radioisotope production could be broadly classified into swimming pool type and tank type reactors. CANDU power reactors currently produce many millions of curies per year of ⁶⁰Co for MDS Nordion’s use in industry and commerce. Studies related to production of other isotopes in power reactors have also been performed. Indeed, while a very few reactors have come online in the past decade, many more have been retired or may retire in coming years. After failure of MAPLE project, there has been unwillingness to built new reactors. Activism and politics has made it so difficult to build new reactors that we are left to use only the reactors we inherited from a nuclear era. Many design considerations and requirements for the production of isotopes in power reactors must be assessed, such as; operator and public safety, minimum impact on station efficiency and reactor operations, shielding requirements during reactor operation with target adjusters and removal of the target adjusters from core, transportation within the station, and finally the processing and shipment off-site. Use of power reactors for isotope production is reviewed.     

Determination of strontium radioisotopes in soils

Summary A method is proposed for determination of radiostrontium in soils which is based on selective strontium separation by liquid-liquid extraction with dicyclohexano-18-crown-6 in chloroform, loading of the extract on a thin-layer plate and TLC separation of strontium and yttrium radioisotopes using a circular procedure. The method allows the separate determination of ⁸⁹Sr and ⁹⁰Sr. The strontium chemical yield is more than 90%, the detection limit is about 0.5 Bk/g, RSD is equal to 2–5%.     

Determination of volatile carboxylic acids in animal wastes by (GC)2 of their benzyl esters

The C₁ -C₆ fatty acids present in various types of heterogeneous animal wastes were isolated by steam distillation and determined as benzyl esters by high resolution gas chromatography. Glass capillary columns, deactivated with barium carbonate and coated with UCON HB 5100, allowed the analysis of benzyl formate, acetate, propionate, isobutyrate, butyrate, isovalerate, valerate, and caproate in less than 20 minutes. Recovery tests, performed on more than 50 different samples, indicated a benzylation yield and an overall efficiency higher than 99%, with a standard deviation of 2.6% (C₅) to 6.0% (C₁). The absolute detection limit ranged from 0.3 picomole (caproic acid) to 1.0 picomole (formic acid).     

Mass selective separation applied to radioisotopes of cesium

A technique that uses the intrinsic mass‐based separation capability of a quadrupole mass spectrometer has been used to resolve spectral radiometric interference of two isotopes of the same element. In this work the starting sample was a mixture of ¹³⁷Cs and ¹³⁴Cs and was (activity) dominated by ¹³⁷Cs. This methodology separated and ‘implanted’ ¹³⁴Cs that was later quantified for spectral features and activity with traditional radiometric techniques. This work demonstrated a ¹³⁴Cs/¹³⁷Cs activity ratio enhancement of >4 orders of magnitude and complete removal of ¹³⁷Cs spectral features from the implanted target mass (i.e. 134). Copyright © 2016 John Wiley & Sons, Ltd.     

Extraction-scintillation method for determining the concentration of radioisotopes

A method is presented for the determination of uranium isotopes in waters by the scintillation-extraction method. By extraction with tributyl phosphate (TBP) in toluene as a liquid scintillator it was established that the presence of TBP in the solvent does not affect the photo-yield substantially. The optimum measuring conditions and the sensitivity of the method have been studied.     

Supply and waste management of radioisotopes in Japan

Radioisotopes have been widely used in Japan. The total number of facilities working with radioisotopes or radiation instruments reached to 5,509 in 1993. The state of supply of radioisotopes and management of radioactive wastes generated from the use of radioisotopes is described.     

Lipids of kenaf wastes

The total phospholipids of kenaf wastes have been characterized qualitatively and quantitatively. Kenaf wastes may serve as an additional source of raw material for obtaining the total phospholipids and a homogeneous PC.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Uzbek Experimental Station of Tannin Crops, Central Asian Division of the Lenin All-Union Academy of Agricultural Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 686–688, November–December, 1986.     

Application of radioisotopes in the field of nuclear medicine

A comprehensive review has been made to discuss the role of various radionuclides of lanthanide series elements in the field of nuclear medicine. The role of several pharmaceuticals labeled with radiolanthanides and used for investigative purposes like measurement of cerebral blood flow, bone density measurement, bone marrow imaging, etc., have been described. The role of lanthanide radionuclides in radiation synovectomy, radioimmunotherapy, etc., have also been discussed. Methods of preparation of some representative radiopharmaceuticals like¹⁵³Sm-EDTMP,¹⁵³Sm-HYP, have been presented. An outline on the production of carrier free radioisotopes of lanthanide series elements has been given.     

Study of secondary implantation of radioisotopes during alpha-particle irradiation

This work presents the recoil and secondary implantation of radioisotopes at different bombarding energies in the range of ~?13 to ~?40 MeV by using an α-particle beam of 50 MeV irradiating a stack of Ag, Ni and Ti metal foils. Activation cross-sections for the produce radioisotopes were calculated and confronted with literature data. The implanted activity is presented as a function of the primary beam energy for six produced radioisotopes ⁵⁷Ni, ⁵⁷Co, ⁶⁵Zn, ⁵¹Cr, ⁴⁸V and ⁴⁶Sc. The use of each of these radioisotopes in engineering experiments based on the nano-thin layer activation is discussed.

     

Removal of cesium radioisotopes from solutions using granulated zeolites

The influence of type of zeolite and the flow rate of solution through the column on the removal efficiency of radioactive cesium ions from solution has been investigated. The analysis of the change in the concentration of cesium ions in the solutions and distribution of cesium ions in the column fillings (granulated zeolites), after passing the solutions through the columns filled with various granulated zeolites (zeolite 4A, zeolite 13X, synthetic mordenite) was performed. On the basis of the results of this study, the conditions for the most efficient removal of cesium ions from solutions have been discussed.