Authors:P. Sivakumar, S. Meenakshi, S. Mohan, R. Subba Rao, and M. Venkataraman
The spent fuel from Fast Breeder Test Reactor of various burnups from 25 to 155 GWd/te is being reprocessed in CORAL (COmpact
Reprocessing of Advanced fuels in Lead shielded cell) using a modified PUREX (Plutonium Uranium Recovery by EXtraction) process.
Total plutonium (Pu238, 239, 240, 241 & 242) concentration in the sample is analysed by HTTA (Thenoyl Trifluoro Acetone) extraction method wherever interference from
other alpha emitting nuclides (Raffinate) and bulk natural uranium (uranium products) are present "as reported by Milyukov
et al. (Analytical chemistry of plutonium, <cite>1967</cite>) and Natarajan and Subba Rao (BARC, pp. 38–43, <cite>2007</cite>)". This method requires the addition of corrosive reagents such as NH2OH.HCl which is a problem in waste disposal for reduction. A salt-free reagent such as Hydroxyurea is studied as a reducing
agent which has the ability to reduce both Pu(VI) and Pu(IV) to Pu(III) "as reported by Zhaowu (260(3):601–606, <cite>2004</cite>) and Zhaowu (262(3):707–711, <cite>2004</cite>)". Pu(III) thus formed can be easily oxidised to Pu(IV) by NaNO2 for the extraction of Pu by HTTA.
The chemical species of carrier-free technetium, which were extractable into a TTA-benzene solution on reduction of96TcO
either with NaBH4 or concentrated HCl, were studied by means of silica gel chromatography. Elution peaks ascribed to the formation of Tc/tta/4 and Tc/tta/3 type complexes were observed. The latter complex was also synthesized by recoil effect of Ru/, p/Tc reactions in -irradiated Ru/tta/3.
The solvent extraction behaviour of tracer zirconium in the TTA-xylene system has been studied. By studying the effect of
TTA concentration, extraction time, and acid concentration for HNO3 and HCl, optimum conditions of zirconium extraction are determined. It is found that zirconium is 98% extracted in one minute
of extraction with 0.5M TTA in xylene from an 8M HNO3 solution. A plot of 1g D versus 1g [TTA] gives a straight line with a slope of 2. This suggests that the zirconium ion is
hydrolyzed and is present as ZrO2+, zirconyl ion, in aqueous solutions.
The chemical behaviour of the95Nb atoms formed by the beta decay of the95Zr-Alizarin S and95Zr-TTA (2-thenoyltrifluoracetone) complexes were investigated. The retention values of95Nb which not complexed with organic reagents at working pH were determined. The values observed were 100% and 80%, respectively. The results are discussed and interpreted to explain the different behaviour on the basis of internal energy values and solvent effects.
Isotopic dilution mass spectrometry has been applied to assess the plutonium concentration in samples such as those obtained
from the dissolution of irradiated uranium fuels in a reprocessing plant. Prior to the analysis, plutonium is taken through
a redox cycle and is separated from uranium and fission products by extraction into TTA-xylene. The extraction procedure,
the standardization of the spike solution and the mass assay of the plutonium are described; typical results under plant conditions
are given. The overall precision of a single measurement of the plutonium concentration is 0.6%, expressed as relative standard
deviation, including the plant sampling error, dilution error and analytical error.
Authors:Pedro Forster, Ademar Lugao, Hermi Brito, and Duclerc Parra
Polymers doped with rare earth complexes are advantaged in film production for many applications in the luminescent field.
In this luminescent polycarbonate (PC) films doped with diaquatris(thenoyltrifluoroacetonate)europium(III) complex [Eu(TTA)3(H2O)2] were prepared and their calorimetric and luminescent properties in the solid state are reported. The thermal behavior was
investigated by utilization of differential scanning calorimetry (DSC) and thermogravimetry (TG). Due of the addition of rare
earth [Eu(TTA)3(H2O)2] into PC matrix, changes were observed in the thermal behavior concerning the glass transition and thermal stability. Characteristic
broadened narrow bands arising from the 5D0 → 7FJ transitions (J = 4−0) of Eu3+ ion indicate the incorporation of the Eu3+ ions in the polymer. The luminescent films show enhancement emission intensity with an increase of rare earth concentration
in polymeric matrix accompanied by decrease in thermal stability.
Authors:S. Mojumdar, M. Sain, R. Prasad, L. Sun, and J. Venart
There are many thermoanalytical techniques but only several of them such as thermogravimetric analysis (TG), high resolution
thermogravimetric analysis (Hi-Res™ TG), derivative thermogravimetry (DTG), differential thermal analysis (DTA), calorimetry,
differential scanning calorimetry (DSC), modulated differential scanning calorimetry (MDSC), evolved gas analysis (EGA), transient
thermal analysis (TTA) and thermal conductivity (k) have selected to be discussed in this paper. Simultaneous thermal analysis (STA) is ideal for investigating issues such
as the glass transition of modified glasses, binder burnout, dehydration of ceramic materials or decomposition behaviour of
inorganic building materials, also with gas analysis. Selected applications of various thermoanalytical techniques from medicine
to construction have also been discussed in this paper.
Authors:Ankita Rao, Pradeep Kumar, and K. Ramakumar
Uranium from different uranium oxide matrices was extracted with tri-n-butyl phosphate–nitric acid (TBP–HNO3) adduct using supercritical carbon dioxide (SC CO2). While 30 min dissolution time at 323 K was sufficient for U3O8 and UO2 powder, UO2 granule (at 333 K) and crushed green pellet (at 353 K) required 40 min. Crushed sintered pellet required 60 min at 353 K
for complete dissolution. Influence of various experimental parameters such as temperature, pressure, volume of TBP–HNO3 adduct, acidity of nitric acid used for preparing TBP–HNO3 adduct and extraction time on uranium extraction efficiency was also investigated. For UO2 powder, temperature of 323 K, pressure of 15.2 MPa, 1 mL TBP–HNO3 adduct, 10 M nitric acid and 30 min extraction time was found to be optimum. ~70% uranium extraction efficiency was obtained
on extraction with SC CO2 alone which increased to 90% with the addition of 2.5% TBP in SC CO2 stream. Extraction efficiency was found to vary linearly with TBP percentage and nearly complete uranium extraction (~99%)
was observed with 20% TBP. Nearly complete extraction was also achieved with addition of 2.5% thenoyltrifluoroacetylacetone
(TTA) in methanol. The optimized procedure was extended to remove uranium from simulated tissue paper waste matrix smeared
with uranium oxide solids.
Authors:Saša Koprivec, Marko Novak, Stanislav Bernik, Metka Voga, Luka Mohorič, and Gregor Majdič
stifle joint ( Cook, 2010 ). Several surgical techniques may be used to treat the damage to the CrCL. The most common are tibial plateau levelling osteotomy (TPLO) and tibial tuberosity advancement (TTA). Both alter the geometry of the tibia in relation
Authors:H. Aly, M. Raieh, S. Mohamed, and A. Abdel-Rassoul
The solvent extraction of divalent iron, cobalt, copper and zinc from perchlorate medium of constant ionic strength (0.1 H+, NaClO4) into a mixture of thenoyltrifluoroacetone (HTTA) and dibenzylamine (DBA) in chloroform has been studied. The extraction
of the different cations were found to increase by more than 103 order of magnitude in presence of DBA. Slope analysis of the extraction results assumed a general formula of M(TTA)2·DBA for the extractable adduct. A stability order of Fe(TTA)2·DBA>Co(TTA)2 ·DBA>Zn(TTA)2·DBA>Cu(TTA)2·DBA has been decumented.