Showing papers in "Radiochimica Acta in 1975"
TL;DR: In this article, ausammenfassung Westcotts j(J,n)-I,unktionen sind für die jeweils vorhandenen (η,γ)und (n,f)-Reaktionen von „Nichtl/v-Nukliden\" im Neutronentemperaturbereich von 0°C bis 2000°C für folgende Nuklide berechnet and in Tabellen zusammengestellt: Ag109, C
Abstract: Zusammenfassung Westcotts j(J,n)-I,unktionen sind für die jeweils vorhandenen (η,γ)und (n,f)-Reaktionen von „Nicht-l/v-Nukliden\" im Neutronentemperaturbereich von 0°C bis 2000°C für folgende Nuklide berechnet und in Tabellen zusammengestellt: Ag109, Cd113, In115, Sm149, Eu151, Eu153, Gd15S, Gd1\", Lu17e, Ta182, Ir191, Ir193, Au1»', Ra22e, Th229, Pa231, Pa233, U232, U233, U234, U235, U23e, U238, Np237, Pu239, Pu241, Am241 und Am243.
49 citations
24 citations
TL;DR: In this article, the WESTCOTT's 7 values for Eu-isotopes as a function of the neutron temperature are calculated with the aid of necessary parameters taken from literatures and their thermal cross sections and resonance integrals are determined without the use of a Cd-filter.
Abstract: The WESTCOTT'S ¡7-values for Eu-isotopes as a function of the neutron temperature are calculated with the aid of necessary parameters taken from literatures and their thermal cross sections and resonance integrals are determined without the use of a Cd-filter. Differentiation of thermal and resonance neutrons is made by conducting the irradiations in different neutron spectra and evaluating the effects of neutron temperature and of resonance component of the effective cross section. Use of the Cd-filter is avoided in order to evaluate the low energy resonances (0.321 eV and 0.461 eV) which contribute for more than 80% to the total resonance integral. The measurements have given thermal cross sections 3148 ± 103 barns 5817 ± 98 barns and 603 ± 23 barns and infinite dilute resonance integrals 3347 ± 952 barns, 6442 ± 1549 barns and 3414 ± 197 barns for Eu (9.3 h-act.), Eu (12.7 y-cat.) and Eu, respectively.
18 citations
TL;DR: The chemical methods for the determination of uranium and plutonium are reviewed in this article, where the four essential steps of the methods, namely, sampling, dissolution, aliquoting and estimation are described.
Abstract: The chemical methods for the determination of uranium and plutonium are reviewed. The four essential steps of the methods, namely, sampling, dissolution, aliquoting and estimation are described. The methods of estimation described include isotope dilution mass spectrometry, redox methods, gravimetry, spectrophotometry, x-ray fluorescence, radiometry and fluorimetry. Of these, the redox methods occupy the major portion of the review in view of their wide-spread use for the accurate estimation of the elements. The redox methods are described under the headings visual indicator methods, amperometric methods, Potentiometrie methods and coulometric methods.
16 citations
12 citations
TL;DR: In this article, a simple and quick method for the extraction separation of molybdenum from uranium from 10 M hydrochloric acid was reported, by a method which was less time consuming than those of earlier authors.
Abstract: In all the commonly used carbon and phosphorous bonded oxygen donor extractante and high molecular weight amines, molybdenum(VI) is easily extracted from concentrated hydrochloric acid solutions as MO02C1~ n + . I n all these extractante uranium(VI) is quantitatively coextracted as U02Cl~ + . The present paper reports a simple and quick method for the extraction separation of molybdenum from uranium from 10 M hydrochloric acid. The separation of molybdenum(VI) from fission products is also suggested, by a method which is less time consuming than those of earlier authors [1-6].
8 citations
8 citations
TL;DR: In Kristallen von K2Cr04 and CrCl3 · 6H 20, die im Cyclotron mit geladenen Teilchen beschossen worden waren, um Mn zu erzeugen, wurden die Ausheilreaktionen untersucht as discussed by the authors.
Abstract: In Kristallen von K2Cr04 und CrCl3 · 6H 20, die im Cyclotron mit geladenen Teilchen beschossen worden waren, um Mn zu erzeugen, wurden die Ausheilreaktionen untersucht. Die Bildung der Tochter Cr erlaubt eine Analyse des Verhaltens von Cr als Funktion verschiedener Parameter. In mit Mn markierten Mangansalzen konnte aufgrund derselben genetischen Verknüpfung wiederum das Verhalten von Cr studiert werden.
7 citations
TL;DR: In this paper, high resolution gamma-spectrometry was carried out on the samples irradiated with thermal and epithermal neutrons, and 23 elements with concentrations in the ppm-range were quantitatively determined.
Abstract: Soils have been analyzed by pure instrumental neutron aetivation analysis. High resolution gamma-spectrometry was carried out on the samples irradiated with thermal and epithermal neutrons. 23 elements with concentrations in the ppm-range were quantitatively determined. The spectra of different activated soils are given with details about selectivity and sensitivity. In some cases of unexpected activities for which elemental Standards have not been provided, the element
7 citations
TL;DR: In this paper, the TBP extraction of thorium, protactinium, uranium and neptunium from binary mixtures of hydrogen halide and sulfuric acid solutions has been investigated.
Abstract: Systematic investigations on TBP extraction of thorium, protactinium, uranium and neptunium from hydrochloric, hydrobromic and sulfuric acid solutions as well as binary mixtures of hydrogen halide and sulfuric acid solutions have been undertaken. Extraction of these elements from low concentrations of pure acid solutions is either low or quite negligible. An appreciable enhancement in extraction of the mentioned elements from mixtures of intermediate concentrations of sulfuric acid and low concentrations of HCl or HBr has been observed. Results were discussed and possible interseparations for the elements concerned were recommended.
6 citations
TL;DR: Sodium chromate (Na2Cr04) suitable for medical diagnostic applications was prepared by irradiating potassium chromate targets in the core of PARR at a thermal neutron flux of 2 χ 10n cm sec as discussed by the authors.
Abstract: Sodium Chromate (Na2Cr04) suitable for medical diagnostic applications was prepared by irradiating potassium Chromate targets in the core of PARR at a thermal neutron flux of 2 χ 10n cm sec. The recoil chromium atoms were separated by extraction of the bulk of Cr(VI) with 0.1 M 4-(5-nonjl) pyridine/benzene from dilute hydrochloric acid solutions and the effluent was purified in an anion exchange column. 98°/0 radiochemical purity and 25mCiCr/mgCr specific activity have been achieved.
TL;DR: In this article, a Schema de separations radiochimiques applique a l'analyse d'echantillons de poisson is decrit, which permet de doser au moins une trentaine d'61ements sur une seuie prise dessai.
Abstract: R^suine L'article decrit un Schema de separations radiochimiques applique a l'analyse d'echantillons de poisson. Oes derniers, irradies aux neutrons thermiques, sont d'abord dissouts dans l'acide nitrique concentre, puis repris par un melange de HF et HNOj. Les separations des differents Clements recherch^s sont effectuees par echange d'ions sur une colonne de resine Dowex I X-8 100—200 mesh sous forme Cl-, au moyen de solutions de HCl, NHiCl et HNO3 de differentes molarites. Les mesures radioactives sont effectuees ä l'aide, soit d'un cristal a puits Nal(Tl), soit d'un detecteur Ge-Li de 15 cm' couple a un analyseur 1024 canaux. La methode, souple et precise, permet de doser au moins une trentaine d'61ements sur une seuie prise dessai.
TL;DR: In this article, the electron paramagnetio resonance of cesium plutonium(IV) nitrate, Cs2Pu(N03)5, has been studied and it is found that the radioactivity of plutonium isotopes involving alpha particle emission produces self-irradiation effects.
Abstract: Electron paramagnetio resonance of cesium plutonium(IV) nitrate, Cs2Pu(N03)5, has been studied. It is found that the radioactivity of plutonium isotopes involving alpha particle emission produces self-irradiation effects. The paramagnetio species/centre that is formed as a result of these self-irradiation processes is identified to be NOj. The expected resonance due to Pu(IV) ion having the electronic ground State could not be detected and this is possibly because the spinlattice relaxation time is very short.
TL;DR: In this article, the effect of gamma irradiation on quaternary ammonium compound, Aliquat-336, concerning fission product, uranium and plutonium extraction and phase disengagement properties was investigated.
Abstract: Organonitrogen compounds, like ter t iary amines and quaternary ammonium salts, have been extensively applied, as liquid anion exchangers, in many analytical and processing procedures for radioactive elements, particularly actinides. Although quaternary ammonium extractante appear to have advantages ever tert iary amines, due to higher extraction power for actinides in nitrate solutions, easier stripping and greater resistance to degradation by nitric acid, they have not been as extensively studied as tertiary amines. As far as radiation stability is concerned, scientific literature is available [1,2] emphasizing the good resistance of amines but only few data are available [3] concerning quaternary extractante. In this paper some investigations are described on the effect of gamma irradiation on an easily available quaternary ammonium compound, Aliquat-336, concerning fission product, uranium and plutonium extraction and of the phase disengagement properties.
TL;DR: In this paper, the effect of radioactivity on the radiocolloid formation of europium has been described, and the results showed that radioactivity does not play an essential role in the formation of radii.
Abstract: The effect of radioactivity on the radiocolloid formation of europium has been described. The centrifugal behavior of radioactive and of nonradioactive europium has been compared as a function of the of the solution at extremely low europium concentrations. The concentration of nonradioactive europium was determined by radioactivation analysis. No difference could be observed between the behavior of radioactive and of nonradioactive europium. The effects of the europium concentration and of other electrolytes have also been studied. Radioactivity does not seem to play an essential role in the radiocolloid formation of europium.
TL;DR: In this paper, the possibility of using macroreticular ion exchange resins A-26 and A-29 for cleaning the used purex process solvent has been investigated, and the distribution co-efficients for Ru-Rh and Zr-Nb have been determined using the solution under three different conditions, i.e., active solution of pu ~ 0.5 as supplied, active solution washed with 1 M Na2C03 accompanied by rise in pu to 5.0; Washed solution equilibrated with IN. HN03 thus bringing down the pa to
Abstract: The possibility of using macroreticular ion-exchange resin A-26 and A-29 for cleaning the used purex process solvent has been investigated. The distribution co-efficients for Ru-Rh and Zr-Nb have been determined using the solution under three different conditions—active solution of pu ~ 0.5 as supplied, active solution washed with 1 M Na2C03 accompanied by rise in pu to — 5.0; Washed solution equilibrated with IN. HN03 thus bringing down the pa to ~0.5. The effects of temperature and particle size of the resins, on the distribution values have been evaluated. There is indication that distribution is preceded at least partly by decomposition of Ru-complex at higher pn and elevated temperature. Use of two different Purex process solutions revealed that distribution ratios are also dependent on the background history of the used solvents.
TL;DR: In this paper, a radio-analytical separation scheme has been devised to isolate radioyttrium from other spallation products and the bulk target material, and Y can thus be recovered quantitatively and in the carrier-free state.
Abstract: Y is of value for neutron applications as the active component of the Y-Be photoneutron source. This isotope is produced at LAMPF by the spallation of Mo targets with mediumenergy protons, and a radioanalytical separation scheme has been devised to isolate radioyttrium from other spallation products and the bulk target material. Y can thus be recovered quantitatively and in the carrier-free state.
TL;DR: Isotope exchange rates have been measured in the U(S04)2-U02S04-H2S04 system as a function of U(IV) concentration, temperature and pa using U( IV) as a tracer.
Abstract: Isotope exchange rates have been measured in the U(S04)2— U02S04—H2S04 system as a function of U(IV) concentration, temperature and pa using U(IV) as a tracer. The order of reaction, reaction rates, and the temperature coefficients have been determined. To explain the observation requires the existence of a basic U ± polymer which does not directly take part in the isotope's exchange process. There are significant differences as compared with the reaction mechanism found in chloride solutions.
TL;DR: The eifect of alcohol on the adsorption of the mentioned elements was found to vary from one element to another, as well as in mixtures of HCl with different alcohols.
Abstract: The present work is an investigation of the adsorption behaviour of thorium, protactinium, uranium, neptunium and plutonium on zirconium phosphate from NH4CI, HCl and HCl-alcohol media. In mixtures of HCl with different alcohols, distribution coefficients were found to depend on both, the alcohol content and the acid concentration. The eifect of alcohol on the adsorption of the mentioned elements was found to Vary from one element to another. Results are discussed and conditions for interseparation of the mentioned elements were given.
TL;DR: In this paper, the Einfluß von Methanol-, Äthanolund Acetonzusätzen auf die Extraktion des Uran(IV) aus salpetersauren Lösungen wurde untersucht.
Abstract: Zusammenfassung Der Einfluß von Methanol-, Äthanolund Acetonzusätzen auf die Extraktion des Uran(IV) aus salpetersauren Lösungen wurde untersucht. Das Extraktion^ verhalten wird unter Berücksichtigung der Lage des Uran(IV)-KomplexgIeichgewichtes und der Verteilung der Säure, des Wassers und des organischen Lösungsmittelzusatzes zwischen den beiden Phasen diskutiert. Am meisten wird das Extraktionsverhalten des Uran(IV) durch die vom organischen Lösungsmittelzusatz (Methanol < Äthanol < Aceton) verursachte Verschiebung der Lage des Komplexgleichgewichtes und der vermehrten Säureextraktion beeinflußt.
TL;DR: In this paper, the separation of lanthanum from mixed fission products is performed by elution through a Dowex 50W-X8 cation exchange column using 0.45 M 2-methyl lactic acid as the eluting agent.
Abstract: The separation of lanthanum is found to be easily performed by elution through a Dowex 50W-X8 cation exchange column using 0.45 M 2-methyl lactic acid as the eluting agent. The elution is preceded by the precipitation of lanthanum and contaminating rare earths aa fluorides and hydroxides. The separation requires about 2 hrs with decontamination factors of 10 calculated for the separation of lanthanum from mixed fission products. Chemical yields were found to range between 40-50%.
TL;DR: The hot atom chemistry of carbon has been extensively studied and general mechanisms for its reaction with hydrocarbons have been proposed [2,3,4,5,6] as discussed by the authors.
Abstract: The hot atom chemistry of carbon has been extensively studied and general mechanisms for its reaction with hydrocarbons have been proposed [2,3]. One of the major products formed following the generation of carbon11 atoms via nuclear processes, such as C(p,pn)C, N(p,a)C, C(n,2n)C, and others, in hydrocarbons is carbon-11 labeled ethylene [4—7], Recently these authors [8] presented additional evidence which further supported the methyne insertion mechanism [2—7,10—14] into methyl groups leading to ethylene-C formation:
TL;DR: In this article, the effect of thermal annealing on the retention of recoil Mn as permanganate in crystalline KMn04 irradiated with fast neutrons at liquid nitrogen temperature has been studied.
Abstract: The effect of thermal annealing on the retention of recoil Mn as permanganate in crystalline KMn04 irradiated with fast neutrons at liquid nitrogen temperature has been studied. The retention after 4 hrs of annealing increases from about 8 % at 196 ° to a maximum of 6 1 % at 180 then decreases at higher temperatures. A single activation energy 0.01 eV) applies to the thermal anneajing process between 196 ° and 40 Extrapolation of the data suggests that below 229 0 no thermal annealing would occur.
TL;DR: In this article, the retention probability of a carbon-14 atom in an organic molecule after beta-decay was shown to be independent of the electronic and steric characteristics of the molecules.
Abstract: After beta-decay of a carbon-14 atom in an organic molecule there is a certain probability that the molecular entity is preserved. This probability denoted as the retention is shown to be independent of the electronic and steric characteristics of the molecules. The investigated compounds included doubly labeled acetylene, propane, cyclopropane, cyclohexane and benzene. The retention was determined by measurement of the activity of the grown-in daughter products. The conclusion from our experimental results is in accordance with theoretical predictions.
TL;DR: In this article, thermal and radiation annealing studies in neutron irradiated ammonium Chromate and ammonium dichromate were made by measuring the Cr distribution among Cr(VI), Cr(III)monomer and Cr( III)-dimer +polymer species following dissolution.
Abstract: Thermal and radiation annealing studies in neutron irradiated ammonium Chromate and ammonium dichromate were made by measuring the Cr distribution among Cr(VI), Cr(III)monomer and Cr(III)-dimer +polymer species following dissolution. The effect of radiation annealing in Cr(III)-doped ammonium dichromate was also investigated. In both neutron irradiated and Cr-doped Chromate salts gamma radiation was found to produce conversion of 'Cr(III)-monomer forming species to Cr(III)-dimer + polymer forming species.