Volume 108, Issue 7

Integral cross sections of the reactions 24 Mg(n,p) 24 Na, 27 Al(n,p) 27 Mg, 27 Al(n,α) 24 Na, 58 Ni(n,d + np) 57 Co and 60 Ni(n,p) 60 Co were measured for the first time using the fast neutron spectrum of a TRIGA reactor extending from 0.5 to 20 MeV. The values obtained in this work were comparable with the recommended values for a pure 235 U prompt fission spectrum. The measured integral value was utilized for integral test of excitation function of each reaction given in some data libraries, namely ENDF/B-VIII.0, TENDL-2017, IRDFF-1.05 and ROSFOND-2010. The integral measurements are generally consistent with the integrated values within 5 %, except for a few cases, e. g. the reaction 60 Ni(n,p) 60 Co, where the data libraries appear to need improvement.

We theoretically investigated the selective back-extraction towards Am(III) over Eu(III) and Cm(III) with two water-soluble 2,9-bis-triazolyl-1,10-phenanthroline derivatives BTrzPhen1 (with two ethanol side chains) and BTrz-Phen2 (with two 1,2-butanediol side chains) by density functional theory (DFT). The molecular geometries and formation reactions of the metal-ligand complexes were modeled by using M(BTrzPhen)(NO 3 ) 3 and [M(BTrzPhen) 2 (NO 3 )] 2+ . Am(III) selectivity over Eu(III) and Cm(III) with BTrzPhen2 was successfully reproduced by back-extraction reaction free energy analysis. Moreover, bonding properties between the metal cations and coordinated ligands (model complexes) were studied in terms of Mayer bond order and quantum theory of atoms in molecule (QTAIM). The difference in covalency between An–N and Eu–N bonds were found to be the key factors for Am(III)/Eu(III) separation, while the Am(III) selectivity over Cm(III) of BTrzPhen2 might be attributed to the competition of donor atoms for cation binding preference toward Am(III) and Cm(III).

To investigate the extraction of uranium(VI) in HCl media by Aliquat ® 336 in 1:99 (v:v) 1-decanol: n -dodecane mixture, our objective is to identify the complexe(s) in the organic phase by time-resolved laser-induced luminescence spectroscopy (TRLS). The extraction mechanism is supposed to involve the formation of [UO2Cl42−⋅(R4N+)2]$[U{O_2}Cl_4^{2 - } \cdot {({R_4}{N^ + })_2}]$ in the organic phase. The occurrence of such a species leads to the presence of the UO2Cl42−${\rm{U}}{{\rm{O}}_2}{\rm{Cl}}_4^{2 - }$ species in the organic solution, which luminescence shows particular features. The luminescence spectra and decay time evolutions are obtained in the organic phase as a function of HCl concentration in the aqueous phase (0.5–6 M). The extraction of UO2Cl42−${\rm{U}}{{\rm{O}}_2}{\rm{Cl}}_4^{2 - }$ is confirmed by the particular spectrum of uranium(VI) in the organic phase, and the typical splitting of the luminescence bands, due to the crystal field effect, is clearly evidenced. The stoichiometry is verified using luminescence intensity variation as a function of the activity of Cl − , and extraction constants are calculated both using the specific interaction theory and Pitzer model. A decomposition of the spectrum of the extracted complex in the organic phase is also proposed. The decay time variation as a function of temperature allows estimating the activation energy of the luminescence process of the extracted complex.

Gaseous volume oxidation (voloxidation) of uranium mononitride (UN) and uranium monocarbide (UC) was investigated in the “NO x -air” atmosphere in the temperature range 298–673 K. It was shown that UN can be converted into uranium water-soluble compounds using an alternative oxidation atmosphere based on NO X -gases. UO 3 and uranyl nitrates are the main products of the reaction. Maximum degree of the UN conversion to water-soluble compounds equal to 80 % was observed at the temperature 565 K. Products of the UC conversion are uranium oxides and oxihydroxides. The observed degree of the UC conversion into water-soluble compounds was less then 20 %.

A metallic alloy of uranium–zirconium and uranium–plutonium–zirconium has been proposed as a fuel for fast reactors, owing to the possibility of achieving high breeding ratio in a short span of time. About 6–10 wt.% of zirconium has been added to these actinide fuels to increase the melting temperature and thermal-mechanical stability. Aqueous reprocessing of the spent metallic fuel generates the high-level liquid waste (HLLW) that contains about 60 % of the total zirconium from the fuel. In view of this, the extraction behavior of a trivalent representative ion, Nd(III) in the presence of Zr(IV) was studied from nitric acid medium using the candidate ligands proposed for trivalent actinide separation from HLLW, such as N , N , N ′ N ′-tetraoctyldiglycolamide (TODGA), and N , N -di-octyl-2-hydroxyacetamide (DOHyA). The extraction was studied as a function of nitric acid concentration, zirconium and neodymium concentration and Nd(III) to Zr(IV) ratio. The findings of dynamic light scattering (DLS) and ATR-FTIR spectral techniques were used for understanding the complex chemistry of Zr(IV) extraction under different conditions. Poor extraction of nitric acid, smaller aggregate size, no third phase formation during the extraction of Zr(IV) and Nd(III) and other unique solvent properties favor the DOHyA molecule in n -dodecane as a solvent for partitioning of trivalent actinides from HLLW generated from metallic fuel reprocessing.

DATA (6-Amino-1,4-diazapine-triacetate) and AAZTA (6-Amino-1,4-diazapine-tetracetate) chelators represent a novel approach representing hybrid-chelates: possessing significant cyclic and acyclic character. It is believed that flexibility of the acyclic part facilitates rapid complexation, whilst the preorganized cyclic part minimizes the energy barrier to complexation and inhibits decomplexation processes. So far, these chelators have been used exclusively with 44 Sc and 68 Ga only. Recent results with nat Cu predict high stabilities for Cu-AAZTA, yet no radioactive labeling of AAZTA or DATA with 64 Cu or any additional radioactive isotope has been reported. We present the one pot synthesis of the bifunctional derivatives AAZTA 5 OMe and DATA 5m OMe and their labeling with 64 Cu. In addition, in vitro stability of the respective complexes are presented.

Background Quantum dots (QDs)-based theranostics offer exciting new approaches to diagnose and therapy of cancer. To take advantage of the unique properties of these fluorescent QDs for different biomedical applications, their structures, size and/or surface chemistry need to be optimized, allowing their stability and functionalities to be tailored for different biomedical applications. Methodology Cadmium telluride/Cadmium sulfide QDs (CdTe/CdS QDs) were synthesized and their structure, size, photostability and functionalities as a bioprobe for detection of Fibrosarcoma tumors were studied and compared with Cadmium telluride (CdTe) QDs. Hence, CdTe/CdS QDs were labeled with 68 Ga radionuclide for fast in vivo biological nuclear imaging. Using gamma paper chromatography (γ-PC), the physicochemical properties of the prepared labeled QDs were assessed. In vivo biodistribution and positron emission tomography (PET) imaging of the 68 Ga@ CdTe/CdS QDs nanocrystals were investigated in Sprague Dawley ® rats bearing Fibrosarcoma tumor. Results CdS shell on the surface of CdTe core increases the size and photostability against high energy radiations; therefore, CdTe/CdS QDs show prolonged fluorescence as compared to CdTe QDs. Conclusion Excellent accumulation in tumor was observed for core/shell quantum dots, but this study showed that small changes in the size of the QDs (+1 nm), after adding the CdS shell around CdTe core, greatly change their biodistribution (especially the liver uptake).

In this study, content of natural radionuclides ( 226 Ra , 232 Th and 40 K) and radon emanating power and radon mass exhalation rate of surface soil samples collected around industrial province Karabük in which the first iron steel plant was built in 1937 were determined by high-resolution γ-ray spectrometry with a high purity germanium detector. The average activity concentration of 226 Ra, 232 Th and 40 K in soil samples were measured as 30 ± 2, 28 ± 2 and 251 ± 20 Bq kg −1 , respectively. The average value of radon emanating power and mass exhalation rate of soil samples were found as 31 % and 19 μBq kg −l s −l , respectively. Assessment of possible radiation hazards to the people due to external exposure was done by estimating the outdoor absorbed gamma dose rate in the air at 1 m above the soil, the corresponding annual effective dose, and the excess lifetime cancer risk. The average outdoor gamma dose rate, annual effective dose, and lifetime cancer risk were estimated as 41 nGy h −1 , 51 μSv y −1 and 2.0 × 10 −4 , respectively. A comparison of the activity and radiological results obtained for the studied samples with the corresponding worldwide average values indicates that the results are below the world average values.

The effect of gamma radiation on the physico-mechanical properties of ethylene propylene diene monomer rubber/styrene butadiene rubber/waste high density polyethylene blend EPDM/SBR/wHDPE (50/50/30) blend reinforced with different types of fillers 10 phr (part per 100 part of rubber, by weight) of HAF-carbon black, Hisil, and prepared modified organo-montmorillonite (OMMT) clay was investigated. The results obtained showed that the organo-montmorillonite (OMMT) clay is the most effective filler for enhancing the physico-mechanical properties of EPDM/SBR/wHDPE vulcanized composites. Scanning electron microscopy and thermogravimetric analysis characteristics were also, studied.