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A novel approach for preferential recovery of Sr from (Sr, Th)O<sub>2</sub>
Vyas, C.K.,Joshirao, P.M.,Shukla, R.,Tyagi, A.K.,Manchanda, V.K. Elsevier Scientific Pub. Co 2012 Journal of hazardous materials Vol.241 No.-
Quantitative leaching of Sr from homogeneous and calcined (Th,Sr) O<SUB>2</SUB> in dilute perchloric acid medium suggests the possibility of reducing the hazardousness of discharged nuclear fuel by separation of <SUP>90</SUP>Sr, a prominent fission product at dissolution stage itself rather than the conventional approach of its recovery from high level nuclear waste. Apart from mitigating the radiotoxicity of the nuclear waste, recovered <SUP>90</SUP>Sr can be employed as a compact heat source and as parent radionuclide for <SUP>90</SUP>Y (used in therapy radiopharmaceuticals), provided it can be made available at desired high purity. Leaching behavior of few other fission products was also investigated to quantify their contamination in leached Sr. Feasibility of employing extraction chromatography using Sr selective resin was explored in perchloric acid medium. In this context, the distribution coefficients of <SUP>85</SUP>Sr(II), Th (IV), Zr(IV), Y(III), Pd(II) as well as <SUP>152</SUP>Eu(III) and <SUP>137</SUP>Cs (I) were determined under varying nitric acid/perchloric acid concentration and under varying loading conditions of metal ions. Perchloric acid medium appears better than nitric acid medium for preferential leaching of Sr from (Th,Sr)O<SUB>2</SUB> as well as for uptake of Sr by Sr selective chromatographic resin.
Kulkarni, A,Ha, S,Joshirao, P,Manchanda, V,Bak, M S,Kim, T American Institute of Physics 2015 Review of scientific instruments Vol.86 No.6
<P>A sensitive radioactive aerosols sensor has been designed and developed. Its design guidance is based on the need for a low operational cost and reliable measurements to provide daily aerosol monitoring. The exposure of diethylene-glycol bis (allylcarbonate) to radiation causes modification of its physico-chemical properties like surface roughness and reflectance. In the present study, optical sensor based on the reflectance measurement has been developed with an aim to monitor real time presence of alpha radioactive aerosols emitted from thorium nitrate hydrate. The results shows that the fabricated sensor can detect 0.0157 kBq to 0.1572 kBq of radio activity by radioactive aerosols generated from (Th(NO3)4 ??? 5H2O) at 0.1 ml/min flow rate. The proposed instrument will be helpful to monitor radioactive aerosols in/around a nuclear facility, building construction sites, mines, and granite polishing factories.</P>
A 2D DNA Lattice as an Ultrasensitive Detector for Beta Radiations
Dugasani, Sreekantha Reddy,Kim, Jang Ah,Kim, Byeonghoon,Joshirao, Pranav,Gnapareddy, Bramaramba,Vyas, Chirag,Kim, Taesung,Park, Sung Ha,Manchanda, Vijay American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.4
<P>There is growing demand for the development of efficient ultrasensitive radiation detectors to monitor the doses administered to individuals during therapeutic nuclear medicine which is often based on radiopharmaceuticals, especially those involving beta emitters. Recently biological materials are used in sensors in the nanobio disciplines due to their abilities to detect specific target materials or sites. Artificially designed two-dimensional (2D) DNA lattices grown on a substrate were analyzed after exposure to pure beta emitters, <SUP>90</SUP>Sr-<SUP>90</SUP>Y. We studied the Raman spectra and reflected intensities of DNA lattices at various distances from the source with different exposure times. Although beta particles have very low linear energy transfer values, the significant physical and chemical changes observed throughout the extremely thin, ∼0.6 nm, DNA lattices suggested the feasibility of using them to develop ultrasensitive detectors of beta radiations.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-4/am4055723/production/images/medium/am-2013-055723_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am4055723'>ACS Electronic Supporting Info</A></P>
Vyas, Chirag K.,Brahmmananda Rao, C. V. S.,Jayalakshmi, S.,Joshirao, Pranav M.,Manchanda, Vijay K. Walter de Gruyter GmbH 2015 RADIOCHIMICA ACTA Vol.103 No.4
<B>Abstract</B><P>The present work investigates the role of increase in the basicity of organophosphorus extractant (dialkylalkyl phosphonates) on the uptake of actinides and fission products vis-à-vis tributyl phosphate (TBP), currently employed as a universal extractant. Two dialkylalkyl phosphonates viz. dibutylpropyl phosphonate (DBPrP) and dibutylpentyl phosphonate (DBPeP) were synthesized, characterized and evaluated for their solvent extraction behavior towards U(VI), Th(IV), Eu(III) and Tc(VII) in nitric acid medium ranging from 0.01–6 M. It was observed that increasing the basicity of the phosphoryl oxygen enhanced the uptake of the actinides and the distribution coefficient values were significantly larger as compared to TBP. The limiting organic concentration (LOC) value was estimated for Th(IV) for these extractants and compared with the TBP system. The separation factors of actinides with phosphonates over Tc(VII) are distinctly better than that with TBP.</P>