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March 29, 2024
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Selective removal of 99 TcO₄ − from radioactive wastewater is a challenging but significant task, which benefits spent fuel reprocessing and radioactive-waste leakage treatment. This work introduces the performance of adsorption ReO 4 − using a series of novel anion exchange resins, namely MAPE-1, MAPE-2, MAPE-3, and MAGD-1, impregnated with functionalized ionic liquids as active sites. They exhibit a high selectivity towards TcO₄ − /ReO₄ − , in a wide pH range of pH 5–11 for ReO₄ − /TcO₄ − adsorption. Among these resins, MAPE-1 has the best adsorption performance for ReO 4 − , with a maximum adsorption capacity of 202.4 mg/g and a high distribution ratio K d of 6.2 × 10⁶ mL/g at pH 7. The adsorption mechanism involves anion exchange between functionalized ionic liquids and TcO₄ − /ReO₄ − , which is supported by X-ray energy dispersive spectroscopy (EDS) and Fourier Transform Infrared spectroscopy (FT-IR) analyses. In addition, X-ray photoelectron spectroscopy (XPS) further illustrates the interaction between the resin and perrhenate.
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March 20, 2024
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Boron isotopic ratio measurement is very important in the nuclear industry because it is used as neutron poison (in the form of boric acid or a B 4 C pellet) and control rod material (B 4 C pellet) in nuclear power plants. Since 10 B has a higher neutron absorption cross-section, enriched 10 B is used in the nuclear industry and the extent of enrichment varies from 50–90 %. Therefore, it is essential to determine the 10 B/ 11 B ratio in boric acid and B 4 C. The prime purpose of the present study is to utilize LA-ICPMS for evaluating 10 B/ 11 B ratio both in solution (boric acid) and solid (B 4 C pellet) without any pre-treatment so that the difficulty in dissolution or powdering process of B 4 C (one of the hardest materials) can be avoided and the B 4 C pellet can be reused. The results obtained from LA-ICPMS for the B 4 C pellet are discussed and compared with the solution ICPMS, TIMS, and LIMS. The solutions of boric acid (natural abundance) and dissolved B 4 C (natural & ∼67 % enriched isotopic composition) were analyzed by LA-ICPMS and validated by liquid sampling ICPMS data.
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March 18, 2024
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With the rapid development of the atomic energy industry, the demand for nuclear fuel has risen, while the limited resources of uranium mines make it difficult to meet the needs of the future development of nuclear energy. Expanding sources of uranium acquisition is necessary, and the enrichment and recovery of precious uranium from uranium-containing wastewater is invaluable. By synthesizing alginate supported potassium manganese ferrocyanide nanocomposites with magnetic response (KMnFC/MA/Fe 3 O 4 ), the high efficiency adsorption and separation of uranium in acidic uranium-containing wastewater can be realized conveniently and quickly. The magnetic composite was characterized by a variety of technical means, and the adsorption behavior of the magnetic material on uranium was studied by static adsorption experiments under different environmental conditions. The adsorption kinetics and isotherm of uranium by KMnFC/MA/Fe 3 O 4 were studied by using some common linear adsorption models. The results show that the adsorption rate of KMnFC/MA/Fe 3 O 4 on uranium is fast, and the adsorption equilibrium can be reached within 90 min. The adsorption process conforms to a pseudo-secondary kinetic model and is dominated by chemisorption. The adsorption of uranium by KMnFC/MA/Fe 3 O 4 magnetic material is single molecular layer adsorption, and the maximum adsorption capacity is 425.5 mg g −1 at 35 °C. KMnFC/MA/Fe 3 O 4 is a promising adsorbent in the field of acidic low-concentration uranium wastewater treatment because of its good effect on the treatment of low concentration uranium wastewater, the concentration of uranium in the wastewater reaches the emission standard after treatment and it is easy to be separated magnetically after adsorption.
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March 18, 2024
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Xanthomicrol (4′,5-dihydroxy-6,7,8-trimethoxyflavone) is the main active component of Dracocephalum kotschyi Boiss leaf extract. It has showed selective cytotoxic activity against some cancer cell lines and little effect on human fetal foreskin fibroblast cells used as nonmalignant control. This study aimed to develop 99m Tc-labeled xanthomicrol and to evaluate its efficiency as a new tumor imaging agent. l , l -Ethylene dicysteine (EC) chelator was conjugated to xanthomicrol. EC-Xanthomicrol was labeled with technetium-99m by using tin chloride as a reducing agent and incubating at room temperature. Radiochemical purity and in vitro stability were analyzed by thin layer chromatography and high-performance liquid chromatography. In vitro cellular uptake and binding profile of radio-conjugate was determined on C6 glioma cells. In vivo bioevaluation and imaging studies of [ 99m Tc]Tc-EC-Xanthomicrol were performed in C6 glioma tumor induced rat at different time points after injection of radio-conjugate. The high radiochemical yield (>95 %) was achieved for [ 99m Tc]Tc-EC-Xanthomicrol which was stable up to 6 h. The radio-conjugate indicated high cell uptake (35.12 % at 2 h) which demonstrated to be specific. Tumor uptake was seen for [ 99m Tc]Tc-EC-Xanthomicrol (1.23 ± 0.14 %ID/g) at 1 h post injection. Scintigraphy confirmed that tumors could be visualized clearly with [ 99m Tc]Tc-EC-Xanthomicrol. The results indicated that [ 99m Tc]Tc-EC-Xanthomicrol has potential to be considered as a new radiotracer in glioma tumor imaging.
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March 15, 2024
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March 12, 2024
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The manuscript reports the synthesis of Dy 3+ incorporated lithium magnesium borate glass by melt quenching technique. FTIR study revealed the presence of both BO 3 as well as tetrahedral BO 4 units through their characteristic frequencies. Photoluminescence (PL) study of unirradiated samples confirmed the presence of Dy dopant in the ‘+3’ oxidation states from the characteristic emissions at 482, 578, 666 and 716 nm corresponding to 4 F 9/2 → 6 H 15/2 , 4 F 9/2 → 6 H 13/2 and 4 F 9/2 → 6 H 11/2 , 4 F 9/2 → 6 H 9/2 transitions, respectively. Thermal neutron and gamma irradiated PL emission and lifetime characteristics were discussed in details based on the different defect centers. Thermal neutron irradiated TL study showed that the material has a broad and single dosimetry glow peak at about 450 K which showed high fading due to low temperature peak. TL based neutron sensitivity of LMB: Dy 3+ was found to be about 37.4 times less than that of standard TLD-100 (LiF: Mg, Ti) powder. The net TL response from about 3 to 83 mSv of neutron dose was found to be linear (Adj. R 2 = 0.9994) which is one of the most desirable properties for dosimetry applications. In addition, the TL trap parameters were evaluated using both deconvolution of TL glow curve and peak shape method as suggested by Chen which were found to be matching with each other.
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March 7, 2024
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In this study, preclinical evaluation and dosimetric estimation of [ 64 Cu]Cu-BPAMD, as a new bone-seeking agent for PET imaging, was studied. [ 64 Cu]Cu-BPAMD was produced with a specific activity of 8.7 GBq/µmol and radiochemical purity (R.P.) of >98 %. The HA binding results showed the binding of nearly all [ 64 Cu]Cu-BPAMD complex to HA at about 15 mg. Biodistribution studies in the male Syrian rats indicated considerable accumulation in the bone with negligible uptake in the other organs. The bone surface and the bone marrow receiving 0.199 and 0.092 mGy/MBq, respectively, are the organs with the most absorbed dose. This study confirms the production of [ 64 Cu]Cu-BPAMD with high R.P. showing high potential for PET-imaging of bone metastases. The lower absorbed dose of mainly human organs compared to 68 Ga-BPAMD can be considered one of the advantages of this new radiolabeled compound.
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March 6, 2024
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February 26, 2024
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The assessment of the migratory and environmental behavior of radioactive nuclides escaping from waste treatment facilities heavily relies on the use of numerical models capable of simulating and characterizing all significant processes of nuclides in complex geological environments. Adsorption models typically encompass the chemical properties of the nuclides themselves and their chemical reactions with the surrounding environment, as well as processes such as ion exchange or physical adsorption. These processes must be taken into consideration in the long-term safety assessment of radioactive waste repositories. The redox-sensitive nuclide 238 Pu, a critical member among transuranic elements, exhibits a diverse range of aqueous forms, and concurrently, it possesses high toxicity. The chemical behavior of 238 Pu shows strong spatial variability with changes in environmental conditions. In this study, we constructed a theoretical model for the migration of nuclides in soil and groundwater environments through indoor static batch experiments and hydrogeochemical simulations. Experimental methods were employed to dissect the micro-scale, irreversible adsorption reaction processes of nuclides and identify their primary existing forms. According to field measurements, the pH of groundwater was recorded as 7.48, with an Eh of 125.7 mV. Introducing a solid-to-liquid ratio of 1:10 g/mL in centrifuge tubes, we measured the radioactive nuclide concentration after achieving adsorption and desorption equilibrium, obtaining adsorption and desorption isotherms. The PHREEQC software was employed to investigate the changes in 238 Pu forms under varying conditions of pH and redox potential. Field measurements provided groundwater pH and Eh values. The activity concentration of the nuclide was measured after reaching adsorption and desorption equilibrium. The results show that the adsorption isotherms of 238 Pu differ from its desorption isotherms, indicating an irreversible adsorption-desorption process. Ion exchange and surface complexation were identified as the main modes of adsorption. PHREEQC simulations revealed that 238 Pu primarily existed in forms such as tetravalent Pu(OH) 4 and trivalent Pu(SO 4 ) 2 − , PuSO 4 + . Pu(OH) 4 accounted for the largest proportion (97%) in the groundwater solution system, while a minimal amount of pentavalent PuO 2 + was present. Environmental factors, such as pH and the presence of ions like SO 4 2− and HCO 3 − , influenced the forms of 238 Pu.
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February 23, 2024
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In this experimental work, guar gum powder was exposed to gamma radiation from a 60 Co source at absorbed doses of 0, 10, 30, 50, 80, 100, 150 kGy at dose rate of 1.62 Gy/s. Raman spectroscopy was applied to measure the intensity of the samples ranging from of 500–4600 cm −1 . The intensity versus Raman shift was evaluated at 3800–4000 cm −1 . Then the curve was fitted linearly. The slope of the lines was determined in each absorbed dose. Results indicated that the absolute values of the slope of each line were enhanced with increasing the absorbed dose. This trend was linear within the absorbed dose ranging from of 0–50 kGy, in which was saturated after 80 kGy. Results showed that guar gum can be applied as a passive dosimeter at radiation processing level.
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February 16, 2024
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Antimicrobial resistance (AMR) as one of the world’s most pressing public health problems needs immediate attention, because it has the ability to affect the human healthcare, agriculture, and veterinary industries. Despite warnings about overuse and their implications, antimicrobials are overprescribed worldwide for humans and animals, which leads to the promotion of resistant microorganisms such as bacteria. Food is a medium for exposure to or transfer of residues of the drugs and can contribute to the burden of the pharmaceuticals associated with development of AMR. Studying on residues of veterinary drugs in foods is essential in the fight against AMR. Herein, we introduce a new method for visualizing the residues of a veterinary drug in animal matrices using radionuclides, called “Depletion Imaging”. Amoxicillin was chosen to be the first antimicrobial for this study. The drug was labeled with [ 62 Zn/ 65 Zn] ZnCl 2 . Radiolabelled amoxicillin and non-labeled amoxicillin were administrated to rainbow trout fish simultaneously. To enable visualization of the remaining residues of amoxicillin in fish, In-vivo positron emission tomography (PET) imaging was done at different intervals from 30 min to 21 days after administration. Evaluation of the amount of radiolabelled amoxicillin in fish was done using a high purity germanium (HPGe) nuclear detector, and enzyme linked immunosorbent assay (ELISA) technique was used for the non-labeled drug. In this study, a comprehensive method for in-house production of zinc radioisotopes was also included. The results showed that depletion imaging and biodistribution study based on gamma spectroscopy of radionuclides in tissues, is a precise method for accurate understanding of the drug’s distribution, metabolic and excretory profile.
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February 14, 2024
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Gamma-ray spectrometry-based isotopic composition analysis is a prerequisite for absolute non-destructive assay of Pu by neutron counting or calorimetry. However, gamma-ray spectrometry can be complicated in samples that are heavily shielded or have a high 241 Am fraction. Herein, for the absolute non-destructive assay of Pu, a simple yet potent empirical methodology combining neutron multiplicity counting and calorimetry is proposed, which obviates the need for gamma-ray spectrometry-based isotopic composition analysis. The approach includes stepwise correlation between the parameters obtained from neutron multiplicity counting, i.e., α (( α , n ) neutron to spontaneous fission neutron ratio), effective mass of 240 Pu, and D (doubles neutron rate) with the thermal power output ( W Pu ) due to radioactive decay (measured by calorimetry). Because D and W Pu both are governed by the Pu isotopic composition, their correlation should be sensitive to the isotopic information in a given sample. Mandatory correction for the 241 Am contribution in W Pu was done using the linear plot between its weight fraction and the corresponding α . The proposed methodology was validated by analyzing several PuO 2 standards containing high 241 Am fraction (0.02–0.09). The measured Pu amounts were within 8 % of the actual values with measurement uncertainties between 8 and 10 %, which shows the potential of the proposed methodology for the assay of samples having high 241 Am content or for the quantification of Pu in heavily shielded samples.
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February 14, 2024
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Synthesis of PSMA-617, a peptide based ligand used in the preparation of nuclear medicine, 177 Lu-PSMA-617, for the treatment of prostate cancer, is demonstrated in 6 steps, starting from appropriately protected amino acid building blocks. A solution phase Boc-strategy was adopted for the synthesis of peptide, wherein deprotection of carbamate group using HCl (g), was employed as the key step. The synthesis furnished PSMA-617 in purity >99.5 % as confirmed by HPLC analysis. ESI-MS and NMR analysis supported the structural integrity of the compound. The synthesized ligand was radiolabelled using 177 Lu to generate the desired radiopharmaceutical, 177 Lu-PSMA-617, in radiochemical purity >98 %, as revealed by radio HPLC and TLC analysis. This establishes its potential as a nuclear medicine for therapeutic application.
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February 14, 2024
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Excitation functions of alpha-particle induced nuclear reactions on nat Sn have been presented in the 11–40 MeV energy range. In the present study, the stacked-foil activation technique followed by offline gamma-ray spectrometry was used to measure the production of 119 Te, 121 Te, 122 Sb and 126 Sb from alpha-particle induced reactions on nat Sn. The TALYS nuclear code was used to calculate the theoretical predictions of the excitation functions of nat Sn( α ,x) nuclear reactions. The measured data of the above-mentioned nuclear reactions were compared with the theoretical predictions and the experimental results available from EXFOR. In this study, covariance analysis was performed to calculate the uncertainty propagation in the measured cross sections.
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February 14, 2024
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Increasing population, food demands and climatic stressors pose an imminent threat to groundwater sustainability in regional aquifer systems globally. Limited availability of surface water and erratic/uncertain rainfall necessitates preservation of groundwater resources, which form reliable fresh water reserves in most of the arid regions. Bhuj Sandstone aquifer is one such fresh groundwater systems in Western India catering the domestic/irrigational needs for over 2 million population. Rapid groundwater depletion in this area warranted a mandatory conservation of groundwater resources for future sustainability. Nuclear techniques using 3 H and 14 C provide estimates of groundwater age that help in planning sustainable groundwater management. In this study, sustainability of deep groundwater was assessed using environmental radioactive isotopes ( 3 H, 14 C). Results indicate that 14 C activity of the groundwater samples varies from 26 to 73.6 pMC (percent modern carbon). Considering the various biases and uncertainties present, multiple correction models were applied to obtain representative groundwater ages by incorporating stable ( 13 C) isotope and hydrogeochemical data. The corrected and representative ages are found to range from 5.8 to 8.6 ka BP (thousand years before present). From the study it can be inferred that central Bhuj aquifer hosts paleo-groundwater while the western part is recently recharged. Therefore, over-exploitation of deep groundwater in central Bhuj aquifer may further lower the water levels and this would have long-term impact on the socio-economic development of Kutch region.
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February 14, 2024
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Glomerular filtration rate (GFR) could be determined more accurately using renal positron emission tomography (PET) than conventional gamma imaging. Copper-64 [ T ½ = 12.7 h, E β+ (max) = 653 keV, β + branching ratio = 17.8 %, 1346 keV γ-photon (0.54 %), EC (43.8 %), β − emission (38.4 %)] in the form of its hydrophilic complex with 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) is proposed as a potent formulation for renal PET imaging. A lyophilized kit was developed for formulation of ∼370 MBq dose of [ 64 Cu]Cu–NOTA complex in a facile single step process using 64 Cu produced by thermal neutron activation in a research reactor. The complex could be synthesized with >99 % yield and retained its integrity even when challenged by apoferritin. The rapid accumulation of [ 64 Cu]Cu–NOTA in the kidney and clearance through urinary path was demonstrated using PET/CT imaging and ex vivo biodistribution study carried out in healthy Wistar rats to elucidate its effectiveness as a renal PET-imaging agent.
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February 14, 2024
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The present paper discusses about the method developed for complete chemical characterization of Zirconium Washed and Dried Frit (WDF) and Reactor Grade ZrO 2 powder which includes nonmetallic element sulphur using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Studies have been carried-out on several important aspects of method development such as effect of matrix on determination of analytes, removal of matrix using different solvents, selection of interference free & sensitive wavelengths, calibration strategies like internal standard & standard addition, optimization of several instrumental parameters which includes RF power, plasma gas flow, nebulizer gas flow, nitrogen purging etc., and are discussed. A % RSD of less than 1 % for Zr and up to 3 % for other elements has been achieved in this method. The developed method has been validated using standard recovery of spiked real time samples with known amount of reference materials. Integrated approach adopted in the development of this method has resulted in reduction of analytical waste generated and also enabled to give quick analytical feedback to production plant for downstream processing.
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February 14, 2024
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Cerium hydroxide, Ce(OH) 4 (Ce), has been synthesised and assessed as a Ru-selective adsorbent for treating alkaline radioactive liquid waste. Infrared spectroscopy, thermal analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy investigations confirmed the successful formation of nanocrystalline Ce from Ce(NO 3 ) 3 ·6H 2 O. Selective removal of 106 Ru from the ion-exchange effluent of intermediate-level liquid waste (ILW) by Ce was assessed using a high-pure germanium (HPGe) gamma-ray spectrometer. The calculated average distribution coefficient ( k D ) was ∼200 mL/g. The percentage removal of 106 Ru using Ce by varying time, [ 106 Ru] and [Ce] was calculated. The adsorption of 106 Ru on Ce follows pseudo-second-order and Freundlich isotherms. The calculated Q max was 93,584 Bq/g. Accelerated leaching studies of the Ru-laden Ce cement product were carried out and found suitable for transport and disposal. Further, Ce-Polyether sulphone (Ce-PES) and Ce-Chitosan (CeC) composites were prepared and assessed for their Ru-uptake capacity for engineering scale application.
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February 14, 2024
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97 Ru is a key radionuclide sought for diagnostic imaging due to its low-energy and intense γ-rays of 215.7 keV and 324.5 keV. New reaction routes to produce this radionuclide are constantly being investigated. A crucial step in carrying out such reactions is a reliable beforehand estimate of the production cross section of radionuclide and optimization conditions through robust theoretical frameworks. Existing literature on α + 95 Mo reaction has been freshly examined to understand the excitation function of 97 Ru. The data have been compared to other reactions of different projectiles on medium-mass targets. The reaction codes pace 4, empire -3.2.2, and talys -1.96 have been employed to decipher the reaction mechanism and check the predictive ability of underlying theoretical models. The yield of 97 Ru at different projectile energies and thick target yield in the optimum energy range has also been determined from the theoretical modeling.
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February 14, 2024
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Plutonium oxalate supernatant requires a treatment step for further recovery of the residual Pu. As the oxalate ion present in the solution poses problems during the recovery of Pu, it needs to be destroyed. In the present work, Mn 2+ based catalytic destruction of oxalate ion was studied in detail, as it could minimize the generation of secondary radioactive waste compared to the conventional process. The effect of various parameters, namely concentrations of HNO 3 , catalyst, oxalic acid and effect of the metal ion has been studied. Moreover, the robustness of the catalytic destruction method along with the kinetics of oxalate destruction reaction has been investigated. The process was also demonstrated with Pu supernatant generated from CORAL at 1 L scale.
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February 14, 2024
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Metal fuels are considered as the promising candidates for future fast breeder reactors. Pyro-chemical reprocessing is the ideal method for reprocessing spent metallic fuels due to the inherent process advantages. Electrorefining run was demonstrated in a hot cell facility with irradiated U-6 wt% Zr alloy at 500 °C using LiCl–KCl eutectic melt. In order to understand the behavior of the actinides and various fission products during high-temperature electrolysis, various process streams, viz., irradiated metal alloy fuel, the eutectic salt, and the cathode deposit were analyzed for the uranium, plutonium, and other fission product contents. Various methods employed for characterizing the process streams and the behaviors of some of the fission products during the electrolysis process are highlighted. The major gamma emitting radionuclides present in the irradiated fuel were 106 Ru, 125 Sb, 134 Cs, 137 Cs, 144 Ce, and 154 Eu. During electrorefining, cesium, cerium and europium were oxidized and dissolved in the molten media, whereas ruthenium and antimony remained in the anode basket. A minor contamination of zirconium was found in the cathode deposit.
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February 14, 2024
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Gallium-68 [ t 1/2 : 67.7 min, β + (89 %)] has application in PET imaging mainly for prostate cancer and neuroendocrine tumours. Gallium-68 is generally obtained from a 68 Ge/ 68 Ga generator. It is therefore an important task to prepare 68 Ge ( t 1/2 = 271 days) radiochemical for the manufacture of 68 Ge/ 68 Ga generator to cater for the needs of various nuclear medicine centres. Germanium-68 has been produced successfully after irradiation of indigenously developed Ga–Ni targets in a 30 MeV cyclotron and chemical processing of the irradiated targets using an indigenous semi-automated module. The Ga–Ni targets were prepared by an electroplating method. The 68 Ge has been radiochemically separated from irradiated Ga–Ni targets using Sephadex G-25 column chromatography. The chemical separation yield and radionuclidic purity of 68 Ge were about 70 % ( n = 3) and about 98.3 % ( n = 3), respectively.
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February 13, 2024
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The handling and analysis of gaseous tritium is of interest for hydrogen isotope separation experiments. In this work, we present an easy-to-handle setup for catalytic oxidation to HTO, recovering all of the initially dosed gaseous tritium as determined by LSC, using CuO as a catalyst at a reaction temperature of 900 °C. Aiming to reduce cocktail waste, the LSC determination was downscaled to a microfluidic setup. The performance was evaluated based on the counting efficiency, which was shown to decrease significantly, as the sample volume was reduced to µl amounts, while no changes were observed over a wide range of sample-to-cocktail ratios.
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February 13, 2024
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The present paper describes a simple method for the determination of uranium in uranium process stream solutions by reversed-phase liquid chromatographic method using C18 column, mixture of α-hydroxy isobutyric acid and methanol as eluent and flow-through spectrophotometer detector. This method has an advantage that interfering elements like rare-earth elements do not retain on the column and elute near the solvent peak thereby not interfering with uranium elution peak. Different eluents and parameters like pH, concentration of eluent are studied for the purpose. The spiking standard recovery was found to be more than 90 %. The developed method has been compared with other techniques and found to be in agreement.
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February 13, 2024
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Detecting nuclear radiation presents a distinctive challenge, particularly with neutrons, which are neutral particles. The method of direct detection involves the utilization of a converter material, acting as an intermediary. Boron plays a pivotal role in this process, reacting with thermal neutrons to generate alpha particles and lithium, with a notable energy release of 2.314 MeV during the 10 B (n,α) 7 Li reaction. This facilitates effective identification and measurement of neutrons in radiation detection systems. The paths of the particles α (for E = 1.474 MeV) and Li (for E Li = 0.842 MeV). The active medium of the nuclear detector, typically a gas, undergoes ionization by these highly charged particles, or they form ion pairs that are subsequently collected by electrodes to produce the signal at the detector’s output. Various deposit methods can be used for this purpose, electrophoresis offers a distinct advantage in terms of both simplicity and precision. This study details the utilization of the electrophoresis technique for the deposition of boron on the tube walls of prototype detectors developed within our laboratory.
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February 6, 2024
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In this study, alpha spectrometry and neutron activation analysis were applied to assess the mass accumulation rate, contamination history, and ecological risk of the Sundarban mangrove sediments. The mass accumulation rates of sediments using 210 Pb dating determined for the first time in this area ranged from 0.068 to 3.20 kg m −2 y −1 , with an average of 0.61 kg m −2 y −1 . The contamination history of 11 metal(loid)s (Al, Ca, V, Cr, Fe, Ni, Cu, Zn, As, Hg, and Pb) was assessed. Different environmental contamination indices suggested that Sundarban mangrove sediments were contaminated by As. Considering different sediment quality guidelines, it was observed that Cr, Ni, and As posed occasional adverse biological effects on marine organisms. Multivariate statistical approaches were applied to elucidate the origin and transport behavior of the studied metal(loid)s in the mangrove ecosystem which suggested that sources of metal(loid) pollution were both anthropogenic and geogenic. The results from this study should improve the knowledge of metal contamination and ecological risk to biota to develop new strategies and enlarge management practices to save sensitive mangrove ecosystems.
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April 7, 2016
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In this study the sorption of cesium was investigated on four different minerals; quartz, plagioclase, potassium feldspar and biotite as well as granodiorite obtained from the Grimsel test site in Switzerland. The experiments were conducted in the presence of the weakly saline Grimsel groundwater simulant by determining the distribution coefficients using batch sorption experiments and PHREEQC-modelling across a large concentration range. In addition, the purity of the minerals was measured by XRD and the specific surface areas by BET method using krypton. The distribution coefficients of cesium were largest on biotite (0.304 ± 0.005 m 3 /kg in 10 – 8 M). Furthermore, the sorption of cesium on quartz was found to be negligibly small in all investigated concentrations and the sorption of cesium on potassium feldspar and plagioclase showed similar behavior against a concentration isotherm with distribution coefficients of 0.0368 ± 0.0004 m 3 /kg and 0.18 ± 0.04 m 3 /kg in 10 – 8 M. Finally, cesium sorption behavior on crushed granodiorite followed the trend of one of its most abundant mineral, plagioclase with distribution coefficient values of 0.107 ± 0.003 m 3 /kg in 10 – 8 M. At low concentrations (< 1.0 · 10 – 6 M) cesium was sorbed on the frayed edge sites of biotite and once these sites are fully occupied cesium sorbs additionally to the Type II and Planar sites. As a consequence, the sorption of cesium on biotite is decreased at concentrations > 1.0 · 10 – 6 M. Secondly cesium sorption on potassium feldspar and plagioclase showed similar non-linear behavior with varying concentration. The results were used to assist the interpretation of cesium diffusion process in the 2.5 year in-situ experiment carried out in the underground laboratory at Grimsel test site in Switzerland (2007–2009).