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1.
V. Gopalakrishnan P. S. Dhami A. Ramanujam M. V. Balarama Krishna M. S. Murali J. N. Mathur R. H. Iyer A. K. Bauri A. Banerji 《Journal of Radioanalytical and Nuclear Chemistry》1995,191(2):279-289
Bench-Scale studies on the partitioning and recovery of minoractinides from the actual and synthetic sulphate-bearing high level waste (SBHLW) solutions have been carried out by giving two contacts with 30% TBP to deplete uranium content followed by four contacts with 0.2M CMPO+1.2M TBP in dodecane. The acidity of the SBHLW solutions was about 0.3M. In the case of actual SBHLW, the final raffinate contained about 0.4% -activity originally present in the HLW, whereas with synthetic SBHLW the -activity was reduced to the background level.144Ce is extracted almost quantitative in the CMPO phase,106Ru about 12% and137Cs is practically not extracted at all. The extraction chromatographic column studies with synthetic SBHLW (aftertwo TBP contacts) has shown that large volume of waste solutions could be passed through the column without break-through of actinide metal ions. Using 0.04M HNO3>99% Am(III) and rare earths could be eluted/stripped. Similarly >99% Pu(IV) and U(VI) could be eluted.stripped using 0.01M oxalic acid and 0.25M sodium carbonate, respectively. In the presence of 0.16M SO
4
2–
(in the SBHLW) the complex ions AmSO
4
+
, UO2SO4, PuSO
4
2+
and Pu(SO4)2 were formed in the aqueous phase but the species extracted into the organic phase (CMPO+TBP) were only the nitrato complexes Am(NO3)3·3CMPO, UO2(NO3)2·2CMPO and Pu(NO3)4·2CMPO. A scheme for the recovery of minor actinides from SBHLW solution with two contacts of 30% TBP followed by either solvent extraction or extraction chromatographic techniques has been proposed. 相似文献
2.
P. W. Naik P. S. Dhami S. K. Misra U. Jambunathan J. N. Mathur 《Journal of Radioanalytical and Nuclear Chemistry》2003,257(2):327-332
Silica-gel has been used as an inert support for the extraction chromatographic separation of actinides and lanthanides from HNO3 and synthetic high level waste (HLW) solutions. Silica-gel was impregnated with tri-butyl phosphate (TBP), to yield STBP; 2-ethylhexyl phosphonic acid, mono 2-ethylhexyl ester (KSM-17, equivalent to PC-88A), SKSM; octyl(phenyl)-N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO), SCMPO; and trialkylphosphine oxide (Cyanex-923), SCYN and sorption of Pu(IV), Am(III) and Eu(III) from HNO3 solutions was studied batchwise. Several parameters, like time of equilibration, HNO3 and Pu(IV) concentrations were varied. The uptake of Pu(IV) from 3.0M HNO3 followed the order SCMPO>SCYN>SKSM>STBP. With increasing HNO3 concentration, D
Pu increased up to 3.0M of HNO3 for STBP, SKSM and SCMPO and then decreased. In the case of Am and Eu with SCMPO, the D values initially increased between 0.5 to 1.0M of HNO3, remained constant up to 5.0M and then slightly decreased at 7.5M. Also, the effects of NaNO3, Nd(III) and U(VI) concentrations on the uptake of Am(III) from HNO3 solutions were evaluated. With increasing NaNO3 concentration up to 3.0M, D
Am remained almost constant while it was observed that it decreases drastically by adding Nd(III) or U(VI). The uptake of Pu and Am from synthetic pressurized heavy water reactor high level waste (PHWR-HLW) in presence of high concentrations of uranium and after depleting the uranium content, and finally extraction chromatographic column separation of Pu and Am from U-depleted synthetic PHWR-HLW have been carried out. Using SCMPO, high sorption of Pu, Am and U was obtained from the U-depleted HLW solution. These metal ions were subsequently eluted using various reagents. The sorption results of the metal ions on silica-gel impregnated with several phosphorus based extractants have been compared. The uptake of Am, Pu and rare earths by SCMPO has been compared with those where CMPO was sorbed on Chromosorb-102, Amberchrom CG-71 and styrene divinylbenzene copolymer immobilized in porous silica particles. 相似文献
3.
R. R. Chitnis P. K. Wattal A. Ramanujam P. S. Dhami V. gopalakrishnan A. K. Bauri A. Banerji 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(3):727-730
The sorption and migration of radiostrontium in a calcareous soil from Yu Zhong county of Gansu province (China) was studied
using batch and column experiments. Sorption isotherms, breakthrough curves and concentration profiles for the untreated soil
and the soil treated to remove CaCO3 were determined, respectively. It was found that radiostrontium is a relatively mobile nuclide in calcareous soil and removal
of CaCO3 from the soil slightly increases the retention ability for radiostrontium. The breakthrough curves were fitted to the analytical
solution of a one-dimensional convection-dispersion transport model that assumes a reversible linear isotherm. Good agreement
was obtained between the measured and predicted concentration profiles. 相似文献
4.
R. R. Chitnis P. K. Wattal A. Ramanujam P. S. Dhami V. Gopalakrishanan A. K. Bauri A. Banerji 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):721-726
This work deals with the batch studies on stripping of actinides extracted by a mixture octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine
oxide (CMPO) and tri-n-butyl phosphate (TBP) in n-dodecane (Truex solvent) from simulated high level waste (HLW) solution.
The stripping of americium and plutonium from acid-bearing CMPO-TBP mixture is carried out using a mixture of weak acid, weak
base and complexing agent as strippant. A mixture of formic acid, hydrazine hydrate and citric acid appeared to be best suited
for efficient stripping of americium and plutonium. With appropriate modifications in the concentration of individual constitutents,
this strippant can be used for the recovery of actinides from loaded Truex solvent with any acid content. 相似文献
5.
N. Shinohara Y. Hatsukawa K. Hata N. Kohno M. Andoh H. H. Saleh W. S. Charlton T. A. Parish S. Raman 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(3):631-638
For nuclear transmutation of minor actinides, delayed neutron emission measurement for241Am was carried out in thermal neutron irradiation location. The neutron capture cross sections of241Am were also measured radiochemically. The transmutation process of241Am in reactor is discussed by calculating the yields of minor actinides with the nuclear data measured in this study and the
evaluated values. The accelerator driven transmutation of minor actinides by high-flux neutrons from spallation reactions
is also presented. 相似文献
6.
The estimation of low level alpha activity is difficult in waste samples containing large concentration of salts and beta–gamma
activity. In the present study, the feasibility of gross alpha-activity measurement for simulated high level waste (SHLW)
in solution medium by alpha-track registration technique has been attempted. The results showed that it is possible to use
this technique for gross alpha-activity estimation of ~200 Bq/mL in solution medium with a precision and accuracy of ~30%.
The importance of measuring 200 Bq/mL alpha activity in SHLW solutions is that this value corresponds to about 4,000 Bq/g
activity in the solid medium which is the safe disposable limit. The advantage of this method over other methods is that it
is not sensitive to beta–gamma emitters and salts and is very simple and inexpensive. 相似文献
7.
8.
J. P. Shukla V. G. Katarni R. K. Singh 《Journal of Radioanalytical and Nuclear Chemistry》1995,191(2):291-303
The uptake behavior of U(VI), Pu(IV), Am(III) and a few long-lived fission products from nitric acid media by bis(2-ethylhexyl) sulfoxide (BESO) adsorbed on Chromosorb has been studied U(VI), Pu(IV) and Zr(IV) are taken up appreciably as compared to trivalent actinides/lanthanides including some coexisting fission product contaminants which are weakly sorbed on the column. Chromosorb could be loaded with (1.12±0.03) g of BESO per g of the support. Maximum sorption is observed around 4–5 mol·dm–3 HNO3 for both U(VI) and Pu(IV), which are sorbed as their disolvates. The elution of (U(VI) and Pu(IV) from the metal loaded sorbent has also been optimized. Desorption of U(VI) is easily accomplished with dilute nitric acid (ca. 0.01 mol·dm–3)while Pu(IV) is reductively stripped with 0.1 mol·dm–3 NH2OH·HCl. Effective sequential separation of U(VI), Pu(IV) and Am(III) from their several admixtures could be readily achieved from real medium and low level active acidic process raffinates. 相似文献
9.
Dean R. Peterman Leigh R. Martin John R. Klaehn Mason K. Harrup Mitchell R. Greenhalgh Thomas A. Luther 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(2):527-531
A new extractant for the separation of actinide(III) and lanthanide(III) cations, bis(o-trifluoromethylphenyl) phosphinic acid (2) was synthesized. The synthetic route employed mirrors one that was employed to produce the sulfur containing analog bis(o-trifluoromethylphenyl) dithiophosphinic acid (1). Classic radiochemical methods and absorbance spectroscopy were used to study the coordination chemistry of the Am-dithiophosphinic
acid and Am-phosphinic acid complexes. 相似文献
10.
To separate MA(Am,Cm) and some fission product elements(FPs) such as Tc,Pd,Cs and Sr from high level liquid waste(HLLW) systematically,we have been studying an advanced aqueous partitioning process,which uses selective adsorption as the separation method.For this process,we prepared several novel adsorbents which were immobilized in a porous silica/polymer composite support(SiO 2-P).Adsorption and separation behavior of various elements was studied experimentally in detail.Small scale separation tests using simulated HLLW solutions were carried out.Pd(II) was strongly adsorbed by the AR-01 anion exchanger and effectively eluted off by using thiourea.Successful separation of Pd(II) from simulated HLLW was achieved.Tc(VII) also exhibited strong adsorption on AR-01 and could be eluted off by using U(IV) as a reductive eluent.Am(III) presented significantly high adsorbability and selectivity onto R-BTP/SiO 2-P adsorbents over various FPs including Ln(III).The R-BTP adsorbents were fairly stable in 3 M HNO 3,but instable against-irradiation-3M HNO 3.An advanced partitioning process consisting of three separation columns for the target elements separation from HLLW was proposed and the obtained experiment results indicated that the proposed process is essentially feasible. 相似文献
11.
Thorat Vidya Soudamini N. Sengupta Arijit Mishra R. K. Kumar Amar Kaushik C. P. 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(3):627-631
Journal of Radioanalytical and Nuclear Chemistry - A simple, simultaneously multi-elemental, ICP-AES based method was optimized to characterize nuclear high level waste solutions from different... 相似文献
12.
A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are split between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3 h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6 h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically greater than 90%, in contrast to other reported methods using flow injection separation techniques for urine samples where plutonium yields were 70-80%. This method allows measurement of both long-lived and short-lived actinide isotopes. 239Pu, 242Pu, 237Np, 243Am, 234U, 235U and 238U were measured by ICP-MS, while 236Pu, 238Pu, 239Pu, 241Am, 243Am and 244Cm were measured by alpha spectrometry. The method can also be adapted so that the separation of uranium isotopes for assay is not required, if uranium assay by direct dilution of the urine sample is preferred instead. Multiple vacuum box locations may be set-up to supply several ICP-MS units with purified sample fractions such that a high sample throughput may be achieved, while still allowing for rapid measurement of short-lived actinides by alpha spectrometry. 相似文献
13.
Selective separation behavior of silica gel for zirconium in simulated high level radioactive liquid waste 总被引:1,自引:0,他引:1
Y. Q. Zhang R. S. Wang C. Sh. Lin X. Y. Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2001,247(1):205-208
Zirconium in simulated high level radioactive liquid waste (HLLW) was selectively adsorbed and separated by self-made high adsorption activity silica gel. The selective adsorption mechanism was analyzed according to the structure character of self-made silica gel and performance of zirconium in acid simulated HLLW. The results show that the adsorption selectivity of self-made silica gel for zirconium is strong, because zirconium has higher positive charge and zirconium ion hydrolyzes easily. Distribution coefficient of self-made silica gels for zirconium is 53.5 ml/g. There are 6.5 (OH)/nm2 on the surface on self-made silica gels which provide more adsorption activity places, thus self-made silica gels have higher adsorption capacity for zirconium (31.4 mg/g). The elution rate of the adsorption of zirconium on self-made silica gel by 0.2 mol/l H2C2O4 is more than 99%. The solubility of the self-made silica gel in nitric acid is low, the chemical stability of self-made silica gel is very strong. 相似文献
14.
Y. Kondo 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):505-513
The heat and off-gas generation behavior was experimentally examined during a safe chemical denitration, pre- and mild-denitration,
of simulated HLLW with a nitric acid concentration of 2 to 7.5 M. The maximum heat and off-gas generation were no more than
100 cal/s·1 and about 0.8 l/min, respectively. The solution temperature does not reach boiling temperature and no solution
was squirted out from the denitration vessel. The pre-and mild-denitration technique could be considered as one of safe methods
for removing nitric acid from the HLLW with various nitric acid concentrations. The pre- and mild-denitration also has an
advantage to improve the filtration characteristics of precipitates produced by the denitration of simulated HLLW. The denitration
of HLLW with 7.5M nitric acid concentration induced formation of “very easy-to-filter” solid. Moreover, a good filter cake
washing is possible. 相似文献
15.
16.
A. Kumar J. V. Sonawane N. S. Rathore H. N. Kapur A. K. Venugopalan D. D. Bajpai 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(3):469-478
Partitioning of minor alpha-emitting actinides, especially U, Pu and Am from medium active alkaline waste is possible from intermediate level liquid wastes (ILLW) produced during spent fuel reprocessing following Purex process. This paper deals with the efficient removal of alpha-activity from ILLW by solvent extraction process. Counter current batch extraction with O/A ratio 2:1 as well as multistage mixer settler has demonstrated that most of the alpha-activity was removed from the alkaline effluents using 20% Versatic-10 (V-10) in dodecane after giving 3 to 4 contacts, thus converting alkaline waste as non-alpha waste. Under the optimum conditions (pH 9.0-9.5 and VA-10), both Pu(IV) and Am(III) are highly extractable whereas U(VI) is relatively poorly extracted. To assess the applicability of this process for regular treatment of the waste, a feasibility study on pilot plant scale using six stage mixer settler was operated to treat the ILLW. The results indicated that almost >99.90% alpha-emitting actinides are removed. Dilute nitric acid (0.5M HNO3) served as the most efficient strippant for all these actinides. This facilitate an easy regeneration of the extractant which can be recycled. This method is useful in obtaining alpha-free wastes and had positive impact on ease and safety aspects during subsequent waste treatment and long term storage. 相似文献
17.
18.
Nicolas Guérin Kenny Nadeau Sabrina Potvin Jean-Michel Hardy Dominic Larivière 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):1803-1811
This article describes a novel separation scheme developed for an automated system to efficiently separate actinides in individual fractions. The automated pressurized injection (PI) system developed allows precise collection of high-purity actinide fractions (≥99 %) at elevated flow rates (15–30 mL min?1) using two extraction chromatographic TEVA and DGA resins. This system is sufficiently robust to enable the use of highly viscous acid media, limit acid corrosion, and tolerate large amount of gases generated by redox reactions by some of the reagents. The PI system was successfully applied to the separation of actinides in individual fractions (recovery yield ≥97 % for Th, U, Np, Pu, and Am) and shows the absence of cross contamination even with highly concentrated actinide solutions. The methodology was also applied to the measurement of actinides in large spiked soil samples. 相似文献
19.
A method is described for pyrolyzing organic films on surfaces for using chemical ionization to produce mass spectra. Changes in the fingerprints of the organic film after exposure for 1 and 4 days are demonstrated. The chemical composition of the adsorbed organics is markedly different from those of the ambient water. 相似文献