Adsorption of anionic chloro complexes of 59Fe and 195Au on non-ionic resins of macro-reticular type

Adsorption behavior of 59Fe and 195Au on the non-ionic macro-reticular resin, Amberlite XAD-7 is studied. Distribution coefficients (Kd) for both nuclides in hydrochloric acid or lithium chloride solutions above 6M are particularly high. In nitric acid solution below 2M, 195Au is highly adsorbed on the resin but 59Fe is negligible over any concentrations. This resin did not adsorb other important radionuclides such as 54Mn, 60Co, 65Zn, 90Sr, 106Ru, 137Cs and 144Ce at all. Based on such peculiar adsorption behavior, application to selective separation and determination of radio and stable iron in sea water was also studied.     

Radiochemical uses of a non-ionic resinous adsorbent of macro-reticular type

Recently, a new type of resinous adsorbent has been developed as an effective adsorbent for a number of organic materials. The adsorbent has macro-reticular structure and no ion-exchange capacity. This paper deals with the adsorption of typical fission products and induced radionuclides on Amberlite XAD-2, with 8-hydroxyquinoline (oxine) as the organic reagent. It was found that⁶⁰Co,⁵⁹Fe,¹⁴⁴Ce,⁹⁵Zr, and¹⁰⁶Ru were transferred to the adsorbent phase from various solutions, when oxinates of the nuclides were formed in the solutions. Without oxine, most of the nuclides were not adsorbed on the adsorbent.¹³⁷Cs and⁸⁵Sr were not adsorbed on XAD-2 with or without oxine.     

Separation of rare-earth fission product elements from106Ru and137Cs by chloride sublimation

The possibility has been investigated of separating rare-earth fission fragment elements from¹⁰⁶Ru and¹³⁷Cs by high-temperature sublimation (950°C) of chlorides, with their subsequent gas adsorption separation in a quartz tube under a temperature gradient in a flow of the carrier-gas Ar+SOCl₂. The temperature corresponding to the maxima of the element precipitation zones are: 630–660°C (¹⁴⁴Ce), 770–780°C (0.7–6 μg¹⁴⁰La+La), 920°C (1.5 mg Ce or La), 420–450°C (¹⁰⁶Ru), 280–300°C (¹³⁷Cs). The coefficients of element separation have been calculated. For the separation of indicator amounts of rare-earth elements and¹⁰⁶Ru and¹³⁷Cs, fractional sublimation of the chlorides of the latter at 650°C has been used. Rate constants and effective activation energies of the overall processes of chlorination-sublimation of the elements have been determined.     

Versuche zur Trennung von Radionukliden durch Zonen anorganischer Ionenaustauscher auf Filterpapierstreifen

Zusammenfassung An zahlreichen anorganischen Ionenaustauschern, die in Form schmaler Zonen auf Papierstreifen präpariert worden waren, wurde in verschiedenen wäßrigen Medien nach Art der aufsteigenden Papier-Chromatographie das Austauschverhalten einiger Radioisotope untersucht. Aus vielen Einzelresultaten ergaben sich Trennmöglichkeiten für Nuklidgemische mit Hilfe einer, zweier oder dreier Austauscherzonen. Weiterhin konnte ein qualitatives Trennschema für das Spaltproduktgemisch ¹³⁷Cs/^137mBa, ⁹⁰Sr/⁹⁰Y, ¹⁰⁶Ru/¹⁰⁶Rh, ¹⁴⁴Ce/¹⁴⁴Pr und ⁹⁵Zr/⁹⁵Nb ausgearbeitet werden.

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Separation of radionuclides by zones of inorganic ion exchangers on filter-paper strips

A number of various inorganic ion exchangers has been prepared in the form of narrow zones on paper strips. Their exchange behaviour against some radioisotopes has been studied in different aqueous solutions using a technique similar to ascending paper chromatography. From the many results of these experiments possibilities for separating mixtures of nuclides have been derived with the aid of one, two or three zones of exchangers on the paper strips. Finally, a qualitative scheme could be worked out for separating the mixture of the fission products ¹³⁷Cs/^137mBa, ⁹⁰Sr/⁹⁰Y, ¹⁰⁶Ru/¹⁰⁶Rh, ¹⁴⁴Ce/¹⁴⁴Pr and ⁹⁵Zr/⁹⁵Nb.

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Herrn Prof. Dr. Georg Brauer zum 60. Geburtstag freundlichst gewidmet.

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Herrn Prof. Dr. W. Seelmann-Eggebert, dem Direktor des Instituts für Radiochemie im Kernforschungszentrum Karlsruhe, sei an dieser Stelle für die Überlassung von Radionuklidlösungen bestens gedankt.     

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.     

Some aspects of radioactive contamination after Chernobyl accident in Romania

After the Chernobyl disaster, the radioactive cloud passage over Romania beginning with the April 30th, 1986 caused fall-out of different intensities in different regions.. The principal contributors to the radioactive exposure during the month of May and rest of 1986 were the short and medium half-live radionuclides: ¹³²Te+¹³²I, ¹³¹I, ¹⁴⁰Ba+¹⁴⁰La, ¹⁰³Ru+¹⁰³Rh, ¹⁰⁶Ru+¹⁰⁶Rh, ⁹⁵Zr+⁹⁵Nb, ¹³⁶Cs, ¹³⁴Cs, ¹⁴¹Ce, ¹⁴⁴Ce and ¹²⁵Sb. After four-five years only ¹³⁷Cs and ⁹⁰Sr remained significant radioactive contaminants. During May 1986 the grass was the mostly affected component of the environment and it contaminated rapidly the majority of foods. Measurements made on the daily gathered pollen samples and eggs during May 1986 clearly indicated that these samples can be used as bioindicators of radioactive contamination of the atmospheric air and, respectively, for soil and grass. Regarding soil contamination, the higher ^134+137Cs deposits in Romania following the northeast-southwest direction were measured, some of these being above 80 kBq/m². This direction is the same with the cloud passage over Romania during the first week of May 1986 and it was confirmed by measurements in the former Yugoslavia, Albania, Greece, and south of Italy.     

Radionuclide partitioning coefficients in the Sava River ecosystem

The radionuclides⁵⁴Mn,⁶⁰Co,⁹⁰Sr,⁹⁵Nb,⁹⁵Zr,¹⁰³Ru,¹⁰⁶Ru,¹²⁵Sb,¹³¹I,¹³⁴Cs,¹³⁷Cs,¹⁴⁰Ba,¹⁴⁴Ce,²²⁶Ra and²²⁸Ac have been studied in the Sava River environment since the Chernobyl accident in 1986. The measured periphyton concentration ratios (CR) for each radionuclide were correlated with the measured sediment distribution coefficients (K_d) for that radionuclide. The K_d-CR relationships obtained were defined by the equation ln K_d=–0.5 ln CR +7.4. These K_d-CR relationships were assumed to be referable to the Sava River ecosystem and were used to predict the missing soil K_d values and/or the missing CR values for the wide range of radionuclides, respectively. Moreover, the K_d-CR relationship characteristic for the Sava River ecosystem was compared with the K_d-CR relationship proposed by Baes¹ and by Shepard². The characterization of the partition coefficients in the Sava River environment and understanding of the mechanisms affecting radionuclide retardation and bioaccumulation are required for the planning of radioactive waste depositories in the area.     

Electrophilic Substitution Ni(II)→M(II) in Ni2[Fe(CN)6] Gelatin-immobilized Matrix Materials

The electrophilic substitution reactions Ni(II)M(II) (M = Co, Cu, Zn, Cd) occurring in nickel(II) hexacyanoferrate(II) gelatin-immobilized matrix materials on their contact with aqueous solutions of corresponding chlorides MCl2 were studied. During contact, Ni(II) is partly substituted by the other metal to form heteronuclear hexacyanoferrates(II) of nickel(II) and corresponding double-charged ions, and none of the studied reactions involves complete substitution of Ni(II) until the mononuclear hexacyanoferrate(II) M₂[Fe(CN)₆] has formed.     

Chromatographic isolation of144Ce and144Pr from the wastes of irradiated uranium treatment

A two-step chromatographic technique was elaborated to isolate¹⁴⁴Ce,¹⁴⁴Pr from a solution of uranium fission products in 6M HNO₃. The oxidation to Ce(III) by bromate and selective adsorption of¹⁴⁴Ce(IV) on anion exchange column were used to concentrate and purify¹⁴⁴Ce. Some impurities of uranium,⁹⁵Zr,⁹⁵Nb,¹⁰⁶Ru remain in¹⁴⁴Ce solution after the first step of its isolation. The final purification is achieved by passing the 6M HNO₃ solution of¹⁴⁴Ce(IV) through the HDEHP-coated teflon column. The decontamination factors of¹⁴⁴Ce from main fission products are given. 7.2 mCi of (¹⁴⁴Ce+¹⁴⁴Pr) are recovered from each gram of irradiated uranium trioxide with the yield greater than 99%. An improvement of known generator was carried out to elute a purer¹⁴⁴Pr from maternal¹⁴⁴Ce(IV) adsorbed on the anion exchange column.     

Gamma-spectrometric determination of106Ru,134Cs,137Cs and144Ce in the fuel from the Czechoslovak atomic power station A-1

Determination of¹⁰⁶Ru,¹³⁴Cs,¹³⁷Cs and¹⁴⁴Ce in samples of irradiated fuel from the Czechoslovak atomic power station Al is described. The determination is based on gamma-spectrum analysis. The analysis was performed using a Ge(Li) semiconductor detector; for the determination of the isotope mentioned the lines in the energy interval from 400 to 1300 keV were used. The analyses of both dissolved and non-dissolved samples of the fuel were performed. The results of the determinations and their comparison are given in detail.     

Sequential estimation of106Ru,137Cs,and90Sr in urine

A sequential method has been developed for the estimation of¹⁰⁶Ru,¹³⁷Cs, and⁹⁰Sr in urine using beta counting. After completely destroying the organic matter in urine,¹⁰⁶Ru is oxidized to volatile ruthenium tetroxide and allowed to reactin-situ with polyethylene powder;¹³⁷Cs is concentrated on ammonium phosphomolybdate and estimated as tetraphenylborate;⁹⁰Sr is coprecipitated as strontium sulphate and converted to carbonate. The recoveries have been found to be better than 83% for all of the radionuclides. The minimum detection limits are 0.16, 0.85, and 0.14 Bq/dm³ for¹⁰⁶Ru,¹³⁷Cs, and⁹⁰Sr, respectively. Yttrium-90 fraction of⁹⁰Sr is also estimated using sodium nitroprusside as reagent, after allowing it to grow for 14 days.This work forms part of the doctoral work of SRIM.V.R. PRASAD to be submitted to the University of Madras, under the supervision of DR. O.M. SREEDHARAN.     

Chernobyl-derived radiocesium in mosses in the Black Sea area

Radiocesium (¹³⁴Cs and¹³⁷Cs) activity levels in mosses from the Black Sea area, northern Turkey, are reported following the Chernobyl accident during the period of 1989–1991. The cesium radionuclides were detected and measured in all the samples but other longlived radionuclides such as¹⁴⁴Ce and¹⁰⁶Ru were measured in only one sample. The present data support the fact that radioactivity monitoring in mosses can be useful to determine the lasting effect of radioactive contamination.     

Competitive transport of toxic metal ions by polymer inclusion membranes

The paper gives a short overview of application of polymer inclusion membranes (PIMs) for separation and removal of metal ions. Investigation of the selective removal of toxic metal ions, i.e. Cr(VI), Cd(II), Zn(II) from acidic chloride aqueous solutions, as well as trace radionuclides, i.e., ¹³⁷Cs, ⁹⁰Sr and ⁶⁰Co from wastewaters using transport across polymer inclusion membranes was studied. The carriers, i.e., tri-n-octylamine for anionic metal species, as well as dibenzo-21-crown-7, tertbutyl-dibenzo-21-crown-7, and dinonylnaphtalenesulfonic acid for metal cations were incorporated into polymer inclusion membranes composed of cellulose triacetate as a support and o-nitrophenyl pentyl ether as a plasticizer. Selective transport of chromium(VI) over zinc(II) and cadmium(II) chloride complexes through PIMs was observed. Competitive transport of trace radionuclide ions, i.e., ¹³⁷Cs, ⁹⁰Sr, and ⁶⁰Co from NaNO₃ aqueous solutions across polymer inclusion membranes containing a mixture of dinonylnaphtalenesulfonic acid, and dibenzo-21-crown-7 as the carrier provide the selectivity order Cs(I)>Sr(II)>Co(II).     

Wide-area aquatic sampling and analysis for the detection of nuclear proliferation

Nuclear proliferation signature radionuclides can be delivered to the aquatic environs via direct liquid discharges or atmospheric routes. The candidate radionuclides for detection are ³H, ⁹⁰Sr, ⁹⁵Nb, ⁹⁵Zr, ⁹⁹Tc, ¹⁰⁶Ru, ¹²⁵Sb, ¹²⁹I, ¹³⁴Cs, ¹³⁷Cs, ¹⁴⁴Ce, ¹⁴⁷Pm, ^NatU, ²³⁸U, ²³⁵U, ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, and ²⁴¹Pu. The criteria for detection are the limits of radionuclide analysis, the nature and variability of background oncentrations, and the transport characteristics between the source and sample site. The type of sample to be taken is determined by the signature radionuclides sorption on/in the media sampled. Non-sorbing radionuclides such as ³H, ⁹⁹Tc, and ¹²⁹I are in the water, whereas the Pu radionuclides are in the transported sediments. Results are discussed for monthly releases of radionuclides such as ⁹⁰Sr, ¹³⁷Cs, and ²³⁹Pu for variable flow-rate conditions with typical backgrounds and typical detection limits.     

Separation of182Ta from biological material by precipitating it as tantalum phosphate

The method of the separation of¹⁸²Ta from urine and stool by precipitating as tantalum phosphate was elaborated. The conditions of Ta phosphate precipitation as well as coprecipitation of⁴⁵Ca,¹⁰⁶Ru,¹⁴⁴Ce,¹⁴⁷Pm,¹⁵²Eu,⁶⁰Co,⁹⁰Sr,⁹⁰Y,⁹⁵ Zr,⁹⁵Nb and U were studied. The results show that tantalum can be separated from all macrocomponents of the mineralized biological material and from the great number of radionuclides which can be present in the sample.     

Tri-iso-amyl phosphate (TAP): An alternative extractant to tri-butyl phosphate (TBP) for reactor fuel reprocessing

Tri-iso-amyl phosphate (TAP), an indigenously prepared extractant was utilized for reactor fuel reprocessing and compared with tri-butyl phosphate (TBP) and tri-n-hexyl phosphate (THP). The potential of these extractants was found to be in the order TAP>THP>TBP by calculating the acid uptake value (K _H). The effect of various parameters such as solvent degradation due to acid hydrolysis, radiation effect, decontamination factor and phase separation were investigated and it was found that TAP was always a better extractant in comparison to THP and TBP. In addition to this, the extraction of fission product contaminants such as ¹⁴⁴Ce, ¹³⁷Cs, ¹⁰⁶Ru, ⁹⁵Zr was almost negligible, even at very high nitric acid concentrations in the aqueous phase, indicating the potential application of TAP in actinide partitioning. Sodium carbonate solution or acidified distilled water was a good strippant for U(VI), similarly, uranium(IV) nitrate stripped Pu(IV) from the organic phase.     

Performance of immobilized Saccharomyces cerevisiae in the removal of long lived radionuclides from aqueous nitrate solutions

The efficiency of tailor made immobilized Saccharomyces cerevisiae(biomatrix) for the sorption of radionuclides ²³³U, ²³⁹Pu, ²⁴¹Am, ¹³⁷Ce, ¹⁴⁴Cs, ^103,106Ru and ⁹⁰Sr from aqueous nitrate solutions at different pH was studied. Effect of ionic strength, anionic components, initial metal concentration and particle size of the biomatrix on the sorption of metal ions were investigated. At pH in the range of 1 to 2 more than 95% sorption of U, Pu, Am and Ce could be accomplished, while that of Ru was 65%. Sorption of Cs and Sr were negligible under similar conditions. The metal ion-biomatrix system for Pu, Am and Ce reached equilibrium within 60 minutes. In the case of U, equilibrium attained in 100 minutes. The presence of anionic components, Cl^-, C₂O₄ ^2-, CH₃COO^-, NO₃ ^- and SO₄ ^2- (up to 0.5 mol^.dm^-3 of their individual concentration) in the aqueous solutions has no effect on the sorption of Pu by the biomatrix. Sorption of U, Pu, Am were observed in the presence of several cationic impurities such as Al, Be, Cd, Cr, Fe, Mn, Pb, Ce, Dy, Eu, Gd and Sm. Metal sorbed on the biomatrix could be leached out using 5 mol^.dm^-3 nitric acid. The I.R spectra of U bearing biomatrix suggest chemical interaction of uranyl ion with the biomatrix.     

A spectrophotometric method for the determination of thorium with acid alizarin black Sn

Acid alizarin black SN reacts with thorium at pH 4.2 to give a highly sensitive colour reaction with thorium, ε₆₀₀ mμ = 28,000. There is no interference from Ba, Ca, Cd, Ce(III), Gd, Hg, La, Mg, Mn, Pb, Pr. Sm, Sr, Zn, Zr, Cl(su-), CN(-), I(su-), NO(3-), SO₄^2-. The interferences of Al, Bi, Co, Cu, Fe, Ni, Mo, Sb, Sn, Ti and W may be overcome by addition of masking agents. Only U(VI) and V(V) still interfere and these can be determined sequentially with the thorium. The nature of the complex is studied and the mode of its formation.     

A group separation scheme for radiochemical neutron activation analysis for 24 trace elements in rocks and minerals

A group separation scheme has been developed for radiochemical neutron activation analysis for Ca, Cu, Zn, Ga, Rb, Sr, Zr, Sb, Cs, Ba, La, Nd, Sm, Eu, Gd, Tb, Ho, Tm, Yb, Lu, Hf, Ta, W and Th in a wide variety of silicate rocks and minerals, especially ultrabasic rocks and mafic minerals. The samples are decomposed in a hydrofluoric acid-nitric acid mixture in a PTFE-lined bomb. The soluble fluorides (Cu, Zn, Ga, Rb, Zr, Sb, Cs, Ht, Ta, W and Pa) are separated into three groups of elements by sequential elution from a cationexchange resin. The insoluble fluorides (Ca, Rb, Sr, Cs, Ba and REE) are dissolved and purified from interfering iron and scandium activities by extraction with tri-n-butyl phosphate. If necessary, the four main groups can be purified further from interfering activities such as ⁵⁹Fe, ⁵¹Cr and ⁶⁰Co. The accuracy and reproducibility of the procedure were tested by repeated analysis of U.S. Geological Survey standard granite G-2, andesite AGV-1 and dunite DTS-1.