[en] The present talk will focus on the role of mass spectrometry in NFS in general; besides that, the various chromatographic methods developed towards separation of actinides and lanthanide fission products and characterization of dissolver solutions of nuclear reactor fuels using TIMS and some applications of using ICP-MS as well

[en] An on-line gamma monitor, based on a well-type NaI(Tl) crystal, was set up to detect gamma-active species eluting from the column in a high performance liquid chromatograph (HPCL). The radionuclides, ⁶⁰Co and ⁵⁴Mn were separated using a dynamic ion exchange mode. The sensitivity of detection was compared with that of the post column derivatization followed by photometric detection method. (author). 1 fig

[en] Dynamic ion-exchange based chromatographic techniques were developed and demonstrated at CG, IGCAR for the rapid separation of individual lanthanides, some actinides (Th, U, Pu and Am) and transition metal ions. A rapid separation procedure for the isolation of individual lanthanides on a monolithic C₁₈ column using camphor-10-sulfonic acid (CSA) as the ion-pairing reagent with α-HIBA as the complexing reagent has been developed and demonstrated in less than 2.8 minutes, the fastest LC technique reported till date in literature. This technique was demonstrated for the assay of uranium, plutonium and lanthanides present in the dissolver solution of a fast reactor fuel discharged at about 155 GWd/ton. The technique was demonstrated at the laboratory for measuring the concentrations of fission product lanthanides such as La, Ce, Pr, Nd and Sm in the dissolver solution of thermal as well as fast reactor fuel

[en] Earlier studies carried out in our laboratory indicated that Tri-sec-butyl phosphate (TsBP) is a potential extractant for U/Th separation. Also, the third phase formation tendency of TsBP is lower compared to its isomers, Tri-n-butyl-phosphate (TBP) and Tri-iso-butyl phosphate (TiBP). In this context, the extraction and third phase formation behaviour of 1.1 M solutions of TiBP and TsBP in n-dodecane in the extraction of Th(IV) from 1 M HNO_3 at 303 K over a wide range of Th concentrations were investigated in the present study and the results are compared with the literature data on TBP system. Concentrations of Th(IV) and HNO_3 loaded in the organic phase before third phase formation (biphasic region) as well as in third phase and diluent-rich phase after third phase formation (triphasic region) were measured as a function of equilibrium aqueous phase Th(IV) concentration. The density of loaded organic phase was also measured at various Th(IV) concentrations. The extraction profiles in the biphasic region indicated that extraction of Th(IV) by TBP is higher than that of TiBP which in turn is higher than that of TsBP. Extractant concentration in the diluent-rich phase and third phase was measured for the triphasic region.

[en] The separation efficiency of individual lanthanides depends on the stability constant of the metal-ligand complex. Therefore, stability constant data of lanthanide complexes is important in the development of high performance separation procedures. The dynamic ion exchange HPLC technique was employed at our laboratory to estimate the stability constant of lanthanides with various complexing agents. In these studies, the retention times as well as capacity factors of lanthanides and some actinides were measured as a function of CSA, complexing agent concentrations and mobile phase pH. From these studies, a correlation has been established between capacity factor of a metal ion, concentrations of ion-pairing reagent and complexing agent with the stability constant of lanthanide complex

[en] Spent fuel of uranium-plutonium mixed oxide (MOX) from sodium cooled Fast Breeder Test Reactor (FBTR) was analyzed for at.% burn-up by preferential evaporation method. A sequential pattern of analysis of fission monitor Nd and heavy elements, U and Pu provided an un-interfered isotopic composition. Concentrations of individual elements were determined by isotopic dilution mass spectrometry. The proposed method provides at.% burn-up with an uncertainty of about 4% (compared to ASTM method), is less time consuming, does not involve any chemical separation, reduction in radioactive waste and substantial reduction in the radiation exposure to analyst. (author)

[en] Extraction behavior of tris(2-methylbutyl) phosphate (T2MBP), a higher homologue of tri-n-butyl phosphate (TBP), in the extraction of U(VI) and Pu(IV) from nitric acid media has been evaluated in the present study. Distribution ratios for the extraction of these metal ions by T2MBP were measured as a function of equilibrium aqueous phase nitric acid concentration, extractant concentration and temperature to understand the temperature effects on extraction. Enthalpies of extraction of T2MBP/n-dodecane-U(VI)-HNO₃ and T2MBP/n-dodecane-Pu(IV)-HNO₃ systems were calculated from the distribution ratio data using ''second law'' method. The data reveal that the extraction of U(VI) by T2MBP is exothermic in nature, whereas that of Pu(IV) is endothermic.

[en] This paper presents the results on the use of short columns (3-5 cm long) with small particle size (1.8 μm) for high performance liquid chromatographic separation of individual lanthanides and uranium from plutonium as well as uranium from thorium to achieve rapid separations i.e. separation time as short as 3.6 min for individual lanthanides, 1 min for thorium-uranium and 4.2 min for uranium from plutonium. These advantages can be exploited to significantly reduce analysis time, liquid waste generation as well as dose to operator when radioactive samples are analysed e.g. burn-up determination. In the present work, a dynamic ion-exchange chromatographic separation technique was employed using camphor-10-sulfonic acid (CSA) as the ion-pairing reagent and α-hydroxy isobutyric acid (α-HIBA) as the complexing reagent for the isolation of individual lanthanides as well as the separation of uranium from thorium. Uranium was separated from Pu(III) as well as Pu(IV) by reverse phase HPLC technique. The reverse phase HPLC was also investigated for the isolation and quantitative determination of uranium from thorium as well as lanthanide group from uranium. The dynamic ion-exchange technique using small particle support was demonstrated for measuring the concentrations of lanthanide fission products such as La, Ce, Pr, Nd and Sm in the dissolver solution of fast reactor fuel. Similarly, the assay of uranium in the dissolver solution of fast reactor was carried out using reverse phase HPLC technique. The rapid separation technique using reverse phase HPLC was also demonstrated for separation of lanthanides as a group from uranium matrix; samples of LiCl-KCl eutectic salt containing chlorides of lanthanides in uranium matrix (typically 1: 2000) were analysed. (orig.)

[en] Dissolution of metallic alloys, U-Zr and U-Pu-Zr has been investigated in HNO_3 media. An electro oxidative dissolution technique was also examined. Explosive nature of metallic alloys during dissolution in nitric acid has been investigated. A method has been developed for the determination of zirconium in the presence of uranium and plutonium using a spectrophotometric technique. The influence of HNO_3, uranium and plutonium during the estimation of Zr has been studied. Plutonium interferes in the estimation of Zr and it can be avoided by employing ascorbic acid. The method was employed for the estimation of Zr in samples generated during dissolution of Zr containing alloy fuels. (author)

[en] Dissolution studies with U-Zr as well as U-Pu-Zr based metal alloy samples indicated that complete dissolution of uranium/ plutonium in HNO₃ medium and only partial dissolution of Zr with formation of black residue. It was also observed that there is no enhancement in the dissolution of Zr using EODT. Under various experimental conditions, no explosion was observed during the dissolution of U-Zr based metal alloy fuels in nitric acid medium. A modified spectrophotometric method was developed for the determination of zirconium in a large excess of uranium and plutonium. This method can be applied for the analysis of Zr in U-Zr and U-Pu-Zr alloy samples. The dissolution behaviour of oxidised U-Zr was investigated in HNO₃ or HNO₃-HF medium. U-6 wt% Zr was heated under various experimental conditions e.g. air oxidation, CO₂ oxidation, moist argon. The dissolution of U is found to be complete, whereas dissolution of Zr was about 60-70% in 12M HNO₃. The dissolution of Zr increases with increase in fluoride ion concentration, e.g. about 80-90% in the presence of 0.05M HF in 12 M HNO₃. In case of U-19% Pu-6 wt% Zr, the oxidation was carried out in 30% O₂ in Ar and subsequent dissolution in 12 M HNO₃ showed complete dissolution for U and Pu; but only about 55% for Zr