Rundtischgespräche

Separation of cesium and cobalt from simulated medium active waste (MAW) by coprecipitation with hexacyanocobaltate (III) salts has been discussed. It has been found that coprecipitation of cesium or cobalt from MAW can be carried out successfully by using only potassium hexacyanocobaltate (III). The retention of cesium and cobalt has been studied over a wide range of pH, from zero to 12. A comparison of cobalti-, ferro- and ferricyanide complexes towards the retention of cesium at different pH values has also been made. The retention capacity of cobalticyanide precipitates for cesium and cobalt at pH 1.6 has been reported.     

Investigations on the Treatment of Low- and Medium-Level Radioactive Liquid Wastes

Sorption properties of six different coagulants with respect to the retention of cobalt, caesium, europium and uranium have been studied. The precipitating agents are ferrous sulphate, ferric chloride, aluminium sulphate, tri-sodium phosphate, ferric sulphate and zinc sulphate. The parameters investigated are pH, concentration of the precipitating agents, volume of coagulants vs time and the nature of radionuclides. The data showed that the order of hydroxide volume formed is the following: zinc sulphate > ferric chloride > ferric sulphate > ferrous sulphate, aluminium sulphate, trisodium phosphate. Hexacyanocobaltferrate was used as an adsorbant for caesium from medium-level liquid waste.     

Markierung von Humanserumalbumin mit 131J durch elektrochemische Oxydation von Jodid zum Jod

Es wird über eine Methode und deren optimale Bedingungen berichtet, die eine schnelle, schonende und fernbediente Markierung von Humanserumalbumin mit ¹³¹ J gestattet. Die Markierungsausbeuten, bezogen auf das eingesetzte Jod, sind gut reproduzierbar und liegen bei über 90%.     

Study on the Separation of Carrier-Free Yttrium-90 from Strontium-90

The separation of carrier-free ⁹⁰Y from ⁹⁰Sr by solvent extraction with di-(2-ethylhexyl) phosphoric acid (HDEHP) in dodecane has been investigated in this study. The extraction equilibrium time, the effect of temperature, concentration of extractant, and hydrochloric acid concentration on this extraction system were examined. Based on the studies, the chemical procedure for the separation of carrier-free ⁹⁰ Y from its parent ⁹⁰Sr have been established. The chemical yield of ⁹⁰Y is about 80%. Meanwhile, the ⁹⁰Sr impurity is less than 1×10^?6% and the trace of extractant presented in the final product can be removed by fumed with HNO₃. Consequently, the preparation of millicurie of ⁹⁰Y is quite satisfactory for the adsorption in microsphere resin for radiotherapy applications.     

Treatment of Low and Medium Active Waste by Hexacyanocobaltate(III)

The commercially available CO₃[Co(CN)₆]₂·12H₂O was used in this study as inorganic ion exchanger. The uptake of caesium and cobalt from simulated borate reactor waste on the exchanger was conducted as a function of pH and concentration of caesium or cobalt in solutions. The same study was also carried out on the sorption of caesium from simulated medium active waste. In addition some experiments were carried out on the sorption of radionuclides present in a real medium active waste concentrate.     

Determination of pesticides in honey by ultrasonic solvent extraction and thin-layer chromatography

A rapid method for quantitative determination of atrazine and simazine in honey samples was investigated. The procedure was based on the extraction of pesticides by sonication with benzene:water = 1:1 (v/v) mixture, thin-layer chromatographic separation and quantification by CAMAG Video Documentation system in conjunction with the Reprostar 3. The extraction procedure was optimized with regard to the amount of solvent, duration of sonication and the number of extraction steps. The apparent recovery of pesticides from honey was 92.3 ± 2.4 for atrazine and 94.2 ± 2.8 for simazine, when they were extracted in three steps for 20 min using 20 ml of solvent. Ultrasonic solvent extraction was compared with traditional shake-flask extraction method.     

Transmutation of nuclear wastes using photonuclear reactions triggered by Compton backscattering photons at the Shanghai laser electrongamma source

Based on the facility of the Shanghai Laser Electron Gamma Source (SLEGS),the transmutation for nuclear wastes such as 137Cs and 129I is investigated.It is found that nuclear waste can be transmuted efficiently via photonuclear reaction triggered by gamma photons generated from Compton backscattering between CO2 laser photons and 3.5 GeV electrons.The nuclear activities of 137Cs and 129I are evaluated and compared with the results of transmutation triggered by bremsstrahlung gamma photons driven by ultra intense laser.Due to the better character of gamma photon spectrum as well as the high brightness of gamma photons,the transmutation rate of Compton backscattering method is much higher than that of the bremsstrahlung method.     

Aus der Praxis Behandlung radioaktiver Abwässer in der Leningrader Station

Die Notwendigkeit der Behandlung und Lagerung radioaktiver Rückstände, die beim Betrieb von Kernenergieaneanlagen und bei der Anwendung radioaktiver Nuklide für Forschungs-und instustrielle Zwecke entstehen, stellt die Wissenschaftler und Ingenieure vor eine Reihe komplizierter technologischer und ökonomischer Probleme.

Fur die Bearbeitung und Konzentrieriing flüssiger radioaktiver Rückstände werden verschiedene Methoden (Mitfällung, Destination, Ionenaustausch u. a.) und ihre Kombinationen angewandt. Die Lagerung der Rückstande ist in Form von flüssigen Konzentraten, zementierten oder bituminierten Blöcken usw. möglich. Die richtige Wahl der Bearbeitungstechnologie und ihrer Parameter sowie des Endlagerungsverfahrens für die konzentrierten Rückstände bestimmt in der Folge die ükonomische Effektivität der An- Iagen insgesamt.     

Transmutation of nuclear wastes using photonuclear reactions triggered by Compton backscattering photons at the Shanghai laser electron gamma source

Based on the facility of the Shanghai Laser Electron Gamma Source (SLEGS), the transmutation for nuclear wastes such as ¹³⁷Cs and ¹²⁹I is investigated. It is found that nuclear waste can be transmuted efficiently via photonuclear reaction triggered by gamma photons generated from Compton backscattering between CO₂ laser photons and 3.5 GeV electrons. The nuclear activities of ¹³⁷Cs and ¹²⁹I are evaluated and compared with the results of transmutation triggered by bremsstrahlung gamma photons driven by ultra intense laser. Due to the better character of gamma photon spectrum as well as the high brightness of gamma photons, the transmutation rate of Compton backscattering method is much higher than that of the bremsstrahlung method.     

Erfahrungen aus der Tätigkeit des Koordinierungsrates “Beseitigung radioaktiver Rückstände” der Ständigen Kommission Atomenergie des RGW

By means of the horizontal eleclrophoresis in carrier-free electrolyte solutions could be found conditions for a rapid and selective separation of mendelevium from the products of heavy ion reactions (^2l9Bk + ²²Ne) and the investigation of hydrolysis, reduction and complex formation. As non-isotopic tracers for experiments with Md(III) and Md(II) were used ^152/154Eu and ^87mSr.     

Defects induced by electron irradiation in hollandite ceramics, specific radioactive cesium-host wasteforms: a 57Fe Mössbauer study

Several single phase hollandite ceramics having Ba²⁺ _x Cs⁺ _y (C = Al,Fe)³⁺ _2x+y Ti⁴⁺ _8?2x?y O₁₆ composition have been synthesized and irradiated under external electron beams simulating the β-irradiation of radioactive cesium. These samples have been characterized by ⁵⁷Fe transmission Mössbauer spectroscopy. Mössbauer results show that the irradiation modifies the local arrangements of Ba cations around Fe³⁺ ions by atomic displacement of Ba ions.     

Reinigung von Generator-99mTc durch Lösungsmittelextraktion

Handelsübliche ^99mTe-Generatoren enthalten als Mutternuklid ⁹⁹Mo, das als Spaltnuklid in Kernreaktoren anfällt. Obwohl dieses Molybdän gereinigt ist, sind gewöhnlich Spuren auch anderer Spaltnuklide vorhanden, die beim Melken des Generators mit eluiert werden. (Wir fanden ⁹⁵Nb, ⁹⁹Mo, ¹⁰³Ru, ¹³¹J, ¹³²Te, ¹⁴¹Ce). Für spezielle Untersuchungen, wie etwa für das Studium von Halbwertszeitvariationen des ^99mTc in Abhängigkeit von der chemischen Umgebung, sind höhere Reinheiten erforderlich. Das nachstebend beschriebene Reinigungsverfahren lehnt sich teilweise an eino von Trautmann et al. [1] veröffentlichte Extraktionstechnik an.     

Accelerator-driven sub-critical reactor system (ADS) for nuclear energy generation

In this talk we present an overview of accelerator-driven sub-critical reactor systems (ADS), and bring out their attractive features for the elimination of troublesome long-lived components of the spent fuel, as well as for nuclear energy generation utilizing thorium as fuel. In India, there is an interest in the programmes of development of high-energy and high-current accelerators due to the potential of ADS in utilizing the vast resources of thorium in the country for nuclear power generation. The accelerator related activities planned in this direction will be outlined.     

Bioakkumulation von UO2 2+- und Th4+-Ionen aus Abwässern

Abstract

Using different algea types the bioaccumulation of UO₂ ²⁺ and Th⁴⁺ ions from experimental residual wastes of nuclear facilities was investivated. The retaining degree of these ions on microbiological sorbents decreases as: Scenedesmus quadricauda > Porphyridium cruentum > Spirulina platensis > Calothrix sp.2 > Calothrix sp.1 for UO₂ ²⁺ and Porphyridium cruentum > Spirulina platensis > Scenedesmus quadricauda for Th ⁴⁺. For the same algae it was observed that the retaining degree is much higher for UO₂ ²⁺ than for Th⁴⁺, probably due to the different linking degrees of hydrolysed species of these ions on the macromolecular compounds of the living cells through the chemical functional groups.     

Der Einsatz von Sorbentien räumlich-globulrer Struktur zur Abtrennung radioaktiver Verunreinigungen aus Wasser

Abstract

Possibilities of using a new generation of sorbents have been investigated. Polymers of spatial-globular (spherulitic) structure (RGS polymers) have been tested to separate Cs, Sr and rare earth elements – which can also be radioactive contaminants – from different waters.

RGS polymers are both, solids and highly-disperse systems being extremely permeable to fluids and gases with low pressure decline. They were currently used to clean industrial waste-water.

It is shown that these polymers can be used successfully to separate radionuclides. Polymers RGS-81 and RGS-112 have high distribution coefficients for CS, Sr, Sc, the lanthanide series and Hf in weakly acid solutions. In HF solutions, Sc and Hf can be separated from Cs, Sr and the lanthanides.     

Incorporation of Radioactive Wastes in Cement 1. Effect of some Chemicals on Cement Properties

Effects of some chemicals on the cement hardness were examined. Density, water absorption and porosity of cement mixed with some chemicals were determined. Differential thermal analysis, thermogravimetric and infra-red measurements were carried out. Effects on the hardness of cement by the interaction of chemicals were explained. A modification of the cement containers in Egypt is proposed to overcome the chemical effects investigated.     

Methods of high-sensitive analysis of actinides in liquid radioactive waste

A set of methods has been developed to determine actinides in liquid radioactive waste for solving the problems of radiation, nuclear and ecological safety of nuclear reactors. The main method is based on the radiochemical separation of U, Np–Pu, Am–Cm on ion-exchange and extraction columns. An identification of radionuclides and determination of their content are performed using alpha-spectrometry. The microconcentrations of the sum of the main fissile materials ²³⁵U and ²³⁹Pu are determined with plastic track detectors. An independent method of ²³⁸U content determination is the neutron activation analysis. ²⁴¹Am content is possible to be determined by gamma-spectrometry. A chemical composition of macrocomponents is determined by the atomic-absorption spectrophotometry method.     

Vibrational spectroscopic study of the mineral penkvilksite Na 2TiSi 4O 11·2H 2O – a mineral used for the uptake of radionuclides

We have used vibrational spectroscopy to study the formula and molecular structure of the mineral penkvilksite Na ₂TiSi ₄O ₁₁·2H ₂O. Penkvilksite is a mineral which may be used in the uptake of radioactive elements. Both Raman and infrared spectroscopies identify a band at ～3638 cm^?1 attributed to an OH-stretching vibration of hydroxyl units. The inference is that OH units are involved in the structure of penkvilksite. The formula may be well written as Na ₂TiSi ₄O ₁₀(OH)₂·H ₂O. The mineral is characterised by a very intense Raman band at 1085 cm^?1 and a broad infrared band at 1080 cm^?1 assigned to SiO-stretching vibrations. Raman bands at 620, 667 and 711 cm^?1 are attributed to SiO and TiO chain bonds. Water-stretching vibrations are observed as Raman bands at 3197, 3265, 3425 and 3565 cm^?1. Vibrational spectroscopy enables aspects of the molecular structure of the mineral penkvilksite to be ascertained. Penkvilksite is a mineral which can incorporate actinides and lanthanides from radioactive waste.     

Green ultrasound-assisted extraction of carotenoids from pomegranate wastes using vegetable oils

The objective of this work was to develop a new process for pomegranate peels application in food industries based on ultrasound-assisted extraction of carotenoids using different vegetable oils as solvents. In this way, an oil enriched with antioxidants is produced. Sunflower oil and soy oil were used as alternative solvents and the effects of various parameters on extraction yield were studied. Extraction temperature, solid/oil ratio, amplitude level, and extraction time were the factors investigated with respect to extraction yield. Comparative studies between ultrasound-assisted and conventional solvent extraction were carried out in terms of processing procedure and total carotenoids content. The efficient extraction period for achieving maximum yield of pomegranate peel carotenoids was about 30 min. The optimum operating conditions were found to be: extraction temperature, 51.5 °C; peels/solvent ratio, 0.10; amplitude level, 58.8%; solvent, sunflower oil. A second-order kinetic model was successfully developed for describing the mechanism of ultrasound extraction under different processing parameters.     

Über die Möglichkeit einer strahlenchemischen Reinigung von Abwässern,die Dodezylbenzolsulfonat und Nonylphelylpolyglykoläther enthalten

Es wurde die Möglichkeit des strahlenchemischen Abbaus einiger Detergenzien untersucht, die in Abwässern enthalten sind. Es wurde festgestellt, daß von den oberflächenaktiven Substanzen (OFAS) die den Hauptteil der aktiven Substanz der Detergenzien darstellen, die ionogenen (z. B. Dodezylbenzolsulfonat) bei verhältnismäßig niedrigeren Dosen zersetzt werden als die nichtionogenen (z. B. Nonylphenylpolyglykoläther). Bei gleicher Konzentration beider Stoffe bewirken Dosen in der Größenordnung von 5 bis 6 kGy einen höheren Grad des Abbaus bei Dodezylbenzolsulfonat als Dosen von 10 bis 20 kGy beim Nonylphenylpolyglykoläther. Versuche mit realen Abwässern, die die Präparate ?Biopon”, ?Alkasuper” und ?Kitka” enthalten, bestätigen die erkannte Gesetzmäßigkeit und zeigen die Perspektive eines strahlenchemischen Abbaus für die Reinigung von Abwässern, die ionogenc OFAS enthalten.