Volume 108, Issue 1

Excitation functions were measured by the activation method using the stacked-foil technique for the nat Mo(p,x) 93(m+g),94m,g,95m,g,96(m+g),99m Tc, 92m,95 Nb reactions up to 18 MeV. The experimental results were compared with literature data and theoretical results from EMPIRE-3.2.2 code and TENDL. Special attention was paid to the 100 Mo(p,2n) 99m Tc reaction which is very promising for the production of 99m Tc at a cyclotron. In order to optimize the production conditions of some medically important Tc isotopes, the integral yields were estimated based on the measured cross sections.

One of the methods used to treat different cancer diseases is the employment of therapeutic radioisotopes. Therefore, many clinical, theoretical and experimental studies are being carried out on those radioisotopes. In this study, the effects of level density models and gamma ray strength functions on the theoretical production cross-section calculations for the therapeutic radioisotopes 90 Y, 153 Sm, 169 Er, 177 Lu and 186 Re in the (n,γ) route have been investigated. TALYS 1.9 code has been used by employing different level density models and gamma ray strength functions. The theoretically obtained data were compared with the experimental data taken from the literature. The results are presented graphically for better interpretation.

Highly radioactive 238 Pu-doped and non-radioactive samples of borosilicate glass with chemical compositions and synthesis routine similar to SON68 glass were studied under static saturated leaching conditions in distilled water at 90 °C. Dramatic differences in behavior of the radioactive and model glasses were observed. On time scale of 4 months the radioactive glass is fully covered by mechanically unstable alteration layer, possibly consisting of aluminum hydroxides with small fraction of a separate secondary Pu bearing phase. The model glass remains virtually pristine. Addition of Eu 3+ into the glass allowed examination of the glass radio- and photoluminescence and to assess changes or REE 3+ impurity local environment during self-irradiation and leaching. Photoluminescence spectra suggest more ordered local environment of europium ions in the alteration “gel” than in the bulk glass. Peculiar behavior of the photoluminescence spectra excited at different laser power is observed for the alteration layer and is ascribed to optical bleaching of color centers.

In the present study, surface morphological differences of mixtures of triuranium octoxide (U 3 O 8 ), synthesized from uranyl peroxide (UO 4 ) and ammonium diuranate (ADU), were investigated. The purity of each sample was verified using powder X-ray diffractometry (p-XRD), and scanning electron microscopy (SEM) images were collected to identify unique morphological features. The U 3 O 8 from ADU and UO 4 was found to be unique. Qualitatively, both particles have similar features being primarily circular in shape. Using the morphological analysis of materials (MAMA) software, particle shape and size were quantified. UO 4 was found to produce U 3 O 8 particles three times the area of those produced from ADU. With the starting morphologies quantified, U 3 O 8 samples from ADU and UO 4 were physically mixed in known quantities. SEM images were collected of the mixed samples, and the MAMA software was used to quantify particle attributes. As U 3 O 8 particles from ADU were unique from UO 4 , the composition of the mixtures could be quantified using SEM imaging coupled with particle analysis. This provides a novel means of quantifying processing histories of mixtures of uranium oxides. Machine learning was also used to help further quantify characteristics in the image database through direct classification and particle segmentation using deep learning techniques based on Convolutional Neural Networks (CNN). It demonstrates that these techniques can distinguish the mixtures with high accuracy as well as showing significant differences in morphology between the mixtures. Results from this study demonstrate the power of quantitative morphological analysis for determining the processing history of nuclear materials.

Bis-amidoxime-based claw-like-functionalized marine fungus material (ZZF51-GPTS-DCDA-AM) was prepared for study to absorb the low concentration uranium (VI) from aqueous solution. A series of characterization methods such as SEM, TGA and FT-IR were applied for the functionalized materials before and after modification and adsorption. The experimental results suggested that the amidoxime groups were successfully grafted onto the surface of mycelium powder and provided the special binding sites for the absorption of uranium (VI). In the absorption research, uranium (VI) initial concentration, pH and equilibrium time were optimized as 40 mg L −1 , 6.0, and 110 min by L 4 3 orthogonal experiment, respectively, and the maximum absorption capacity of the prepared material was 370.85 mg g −1 under the optimum batch conditions. After five cycling process, the desorption rate and regeneration efficiency of the modified mycelium were found to be 80.29 % and 94.51 %, respectively, which indicated that the material had an adequately high reusability property as a cleanup tool. The well known Langmuir and Freundlich isotherm adsorption model fitting found that the modified materials had both monolayer and bilayer adsorption to uranium (VI) ions. Simultaneously, the pseudo-second-order model was better to illustrated the adsorption kinetics process. The enhanced adsorption capacity of uranium (VI) by the modified fungus materials over raw biomass was mainly owing to the strong chelation of amidoxime groups and uranium (VI) ions.

The objective of the study is multi elemental analysis of four indigenous Ethiopian tuber crops using instrumental neutron activation analysis (INAA) technique in order to get scientific evidences about the status of essential, trace and non-essential elemental compositions. The samples were collected from Southern and South-western parts of Ethiopia. The irradiation and measurement were performed by using irradiation and counting facilities of the Nigeria Nuclear Reactor-1 (NIRR-1) and a HPGe detector setup at the Centre for Energy Research and Training (CERT), Ahmadu Bello University (ABU), Zaria, Nigeria. A total of 17 elements were determined at various concentration levels. The highest concentrations of K, Mg, Mn and Zn were found in Colocasia esculenta (L.) Schott, whereas; the concentrations of essential and trace elements; Ca, K, Mg, Na, Cl, Mn, and Zn were found to be high in the native Coccinia abyssinica (Lam.) Cogn tuber. The estimated daily intake values of the constituent elements from the consumption of these crops are below upper tolerable limits set by international organizations such as WHO and FAO.

The aim of the present study was to introduction of hydroxyapatite/chitosan nanocomposite as a new radiosynovectomy agent with excellent properties. In this work, the nanocomposite was prepared through a reliable method and characterized using different techniques to elucidate its chemical structure and physiochemical properties. The prepared nanocomposite was successfully radiolabeled with 153 Sm under optimal conditions and with high radiolabelling yield (99 %). The radiochemical purity of the prepared radiopharmaceutical was found to be >99 % as determined by ITLC technique. In vitro stability studies in saline solution and in human serum showed that the radiolabeled nanocomposite retained its stability for at least 6 days. The biodistribution and imaging studies in wild-type rats revealed high retention of the agent into the synovial joints of the knee even at 96 h post-injection, thereby indicating excellent in vivo stability of 153 Sm labeled hydroxyapatite-chitosan nanocomposite. Therefore, the prepared radiopharmaceutical would be a potential therapeutic agent for use in radiosynovectomy procedure.

A valuable tool for external quality control that provides opportunity to improve analytical skills and techniques in the field of radioactivity measurements is participation in proficiency tests (PTs). In this work obtained results from the gamma spectrometry intercomparison for 15 laboratories conducted in May 1986 immediately after the Chernobyl accident for the lucerne sample contaminated with fission products: 140 Ba, 141 Ce, 144 Ce, 134 Cs, 137 Cs, 131 I, 103 Ru, 106 Ru, 95 Zr, are evaluated following the recommendations of the international standard ISO 13528:2005. Environmental radioactivity proficiency tests organized by International Atomic Energy Agency (IAEA) are designed to identify analytical problems, to help members states to maintain their accreditation and to provide knowledge and technology transfer in this area. The Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA) is a world-wide network of analytical laboratories capable to analyzed radioactivity contents, coordinated by IAEA. Institute for the Application of Nuclear Energy (INEP), University of Belgrade, is an official member since 2013. Annual PTs are organized by ALMERA for the network laboratories using sets of different samples. Based on the PT proposition each result should pass accuracy and precision test to be awarded the status ‘Accepted’, otherwise it lies on the status ‘Warning’ or ‘Not Accepted’. INEP was participated in three worldwide open (in 2006, 2007 and 2011) and six (in a period 2012–2016) PTs organized by IAEA and ALMERA. Radionuclide activity concentrations in different environmental matrices were measured using gamma-ray spectrometer with high purity germanium (HPGe) detector. In IAEA worldwide open PTs among 61 results, 74 % were ‘Accepted’ and 26 % were ‘Not Accepted’. In ALMERA network PTs among 70 results, 84.3 % were ‘Accepted’, 4.3 % were ‘Warning’, 11.4 % were ‘Not Accepted’. PT exercises are the best way to identify gaps and problems areas where further development is needed.

Lignite coal is a major and an essential domestic energy source in Turkey. Many environmental problems and human health hazards may arise during lignite coal exploitation, combustion, and waste (fly and bottom ash and slag) disposal. In addition, lignite-burning power plants can be significant contributors to deposition of radiotoxic elements and/or toxic heavy metals on soil and water. The concentrations of thorium (Th) and uranium (U) in a 140 agricultural soil samples collected from the vicinity of a lignite-burning thermal power plant (LBTPP), located in Kangal district of Sivas province in the Central Anatolia region of Turkey, were determined using energy dispersive X-ray fluorescence spectroscopy. The concentrations of Th and U varied from 2.9 to 12.7 μg g −1 with an average value of 5.8 μg g −1 and 0.3–12.3 μg g −1 with an average value of 1.5 μg g −1 , respectively. The radiotoxic elements pollution in agricultural soils was evaluated using pollution indices such as geo-accumulation index ( I geo ), enrichment factors ( E F ), pollution index ( P I ) and Nemerow integrated pollution index ( NIP I ). The average value of I geo , E F and P I estimated for Th and U were found as −1.8, 1.2 and 0.44 and −1.7, 1.7 and 0.58, respectively. The results indicated that the soils around Kangal LBTPP were practically unpolluted to low polluted with Th and U. The NIP I values varied from 0.3 to 4.0 with an average value of 0.6. The evaluation result of NIP I revealed that 86 % of total soil samples were non-polluted.