Solid formation in simulated high level liquid waste of relatively low nitric acid concentration

1994 ◽  
Vol 177 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Y. Kondo ◽  
M. Matsumura ◽  
M. Kubota
Keyword(s):  
Nitric Acid ◽  
Acid Concentration ◽  
Nitric Acid Concentration ◽  
Liquid Waste ◽  
High Level Liquid Waste ◽  
High Level

Extraction behaviour of Am(III) and Eu(III) from nitric acid medium in TEHDGA-HDEHP impregnated resins

2016 ◽  
Vol 104 (11) ◽  
Author(s):  
G. Saipriya ◽  
R. Kumaresan ◽  
P. K. Nayak ◽  
K. A. Venkatesan ◽  
T. Kumar ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Distribution Coefficient ◽  
Acid Medium ◽  
Acid Concentration ◽  
Nitric Acid Concentration ◽  
Liquid Waste ◽  
Nitric Acid Medium ◽  
High Level Liquid Waste ◽  
Extraction Behaviour ◽  
Impregnated Resin

AbstractThe extraction behaviour of Am(III) and Eu(III) from nitric acid medium was studied in the solvent impregnated resins containing extractants such as tetra-bis(2-ethylhexyl)diglycolamide (TEHDGA) or bis-(2-ethylhexyl)phosphoric acid (HDEHP) or mixture of TEHDGA+HDEHP. The rate of extraction of Am(III) and Eu(III) from 1 M nitric acid and the effect of various parameters, such as the concentration of nitric acid in aqueous phase and concentration of TEHDGA and HDEHP in resin phase, on the distribution coefficient of Am(III) and Eu(III) was studied. The distribution coefficient of Am(III) and Eu(III) in HDEHP-impregnated resin decreased and that in TEHDGA-impregnated resin increased, with increase in the concentration of nitric acid. However, in (TEHDGA+HDEHP) – impregnated resin, synergic extraction was observed at lower nitric acid concentration and antagonism at higher nitric acid concentration. The mechanism of Am(III) and Eu(III) extraction in the combined resin was investigated by slope analysis method. The extraction of various metal ions present in the fast reactor simulated high-level liquid waste was studied. The separation factor of Am(III) over Eu(III) was studied using citrate-buffered diethylenetriaminepentaacetic acid (DTPA) solution.

Interference of Zr(IV) during the extraction of trivalent Nd(III) from the aqueous waste generated from metallic fuel reprocessing

2020 ◽  
Vol 108 (7) ◽  
pp. 543-554
Author(s):  
T. Prathibha ◽  
K. Rama Swami ◽  
S. Sriram ◽  
K. A. Venkatesan
Keyword(s):  
Nitric Acid ◽  
Mechanical Stability ◽  
Nitric Acid Concentration ◽  
Liquid Waste ◽  
Aggregate Size ◽  
Metallic Fuel ◽  
High Level Liquid Waste ◽  
Spectral Techniques ◽  
Extraction Behavior ◽  
Fuel Reprocessing

AbstractA 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.

scholarly journals The extraction of SR2+ with dicyclohexano-18-crown-6 in conventional organic solvent and ionic liquid diluents

2020 ◽  
Vol 85 (7) ◽  
pp. 909-922 ◽  
Author(s):  
Zheng Wei ◽  
Yang Gao ◽  
Yu Zhou ◽  
Caishan Jiao ◽  
Meng Zhang ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Nitric Acid ◽  
Distribution Ratio ◽  
Nitric Acid Concentration ◽  
Liquid Waste ◽  
Fission Products ◽  
Carbon Chain ◽  
Radioactive Liquid Waste ◽  
Solvent Systems ◽  
High Level

90Sr (t1/2 = 28.8 a), one of the most significant fission products in high-level radioactive liquid waste (HLLW), contributes to a large part of the heat load and radiation. Removal of 90Sr from the HLLW is beneficial for the final treatment of nuclear waste. In this paper, the extraction of Sr2+ was carried out using dicyclohexano-18-crown-6 (DCH18C6) in a variety of diluents including conventional organic solvents and novel ionic liquid solvents. The effect of several factors, such as nitric acid concentration, crown ether concentration and initial strontium concentration on the extraction of Sr2+ have been studied comprehensively. The higher distribution ratio and the stripping efficiency of Sr2+ were obtained with the binary diluents consisted of n-octanol and acetylene tetrachloride, which were compared with that using pure n-octanol as diluent. As for the CnmimNTf2 (n = 2, 4, 6) ionic liquid solvent systems, the distribution ratio of Sr2+ was much higher in the nitric acid medium with low concentration than in the traditional solvent systems. The results showed that DC2mimNTf2 > DC4mimNTf2 > DC6mimNTf2, which indicated that shorter carbon chain benefits the extraction of Sr2+.

The Application Research of Concentration & Denitration Technology in Advanced Reprocessing Process

2012 ◽  
Vol 560-561 ◽  
pp. 637-643
Author(s):  
Yong Li ◽  
Xue Gang Liu ◽  
Jin Chen
Keyword(s):  
Nitric Acid ◽  
Nuclear Power ◽  
Liquid Waste ◽  
Fission Products ◽  
Extraction Process ◽  
Purex Process ◽  
Current Status ◽  
Spent Fuel ◽  
High Level Liquid Waste ◽  
High Level

The proper management of spent fuel arising from nuclear power production is a key issue for the sustainable development of nuclear energy. While conventional reprocessing process, PUREX process, was successful to recover uranium and plutonium, in recent years some countries have turned to focus on advanced reprocessing process, which features of partitioning of minor actinides (MA) and long-lived fission products(LLFP). Most advanced reprocessing processes under development involve new extractants and additional extraction cycles. In China, TRPO extraction process has been developed to partition MA/LLFP from high-level liquid waste(HLLW) since early 1980’s. In parallel to R&D work on separation technologies, studies on concentration & denitration process have been evolved to prepare feed solutions to suit qualifications of extraction. Industrially, concentration & denitration is the internationally recognized standard to treat HLLW released from PUREX before vitrification. It enables to minimize the volume of interim storage, to restrain the corrosion of storage tank, to recover nitric acid in HLLW and to reduce the required evaporation duty of the vitrification process. Generally, the constitution of concentrated HLLW has little impact on the following vitrification process. But when concentration & denitration acts as pretreatment process of partitioning, the composition of actinides, fission products, and nitric acid in concentrated HLLW solution plays significant role in extraction process. A series of technical issues relevant to the connection between concentration ﹠denitration and extractions should be solved. This paper describes current status of concentration & denitration technology utilized in industry and under reprocessing plants. The specific separation requirements in advanced reprocessing process and challenges to apply concentration & denitration process are addressed. Besides, concentration & denitration process was tested in laboratory to adjust feed solutions for TRPO and Cyanex301 partitioning. Results demonstrate its promising prospect in advanced reprocessing process.

Effect of pKa on the extraction behavior of Am(III) in organo phosphorus acid and diglycolamide solvent system

2018 ◽  
Vol 106 (2) ◽  
pp. 107-118 ◽  
Author(s):  
K. Rama Swami ◽  
R. Kumaresan ◽  
P. K. Nayak ◽  
K. A. Venkatesan ◽  
M. P. Antony
Keyword(s):  
Nitric Acid ◽  
Metal Ions ◽  
Phosphinic Acid ◽  
Liquid Waste ◽  
High Level Liquid Waste ◽  
Single Cycle ◽  
Cyanex 272 ◽  
Extraction Behavior ◽  
Trivalent Actinides ◽  
High Level

AbstractA combination of neutral and acidic extractant has been proposed for the single-cycle separation of trivalent actinides from high-level liquid waste (HLLW). The nature of acidic extractant in the combined solvent formulation plays a profound role in deciding the extraction and stripping of trivalent actinides. Therefore, the extraction behavior of Am(III) in a solution of tetra-bis(2-ethylhexyl)-diglycolamide (TEHDGA) and acidic extractant (HA) was studied from nitric acid medium. The acidic extractants chosen were bis(2-ethylhexyl)phosphoric acid (HDEHP), bis(2-ethylhexyl)phosphonic acid (PC88A) and bis(2,4,4-trimethylpentyl)phosphinic acid (CYANEX-272) whose pKavalues were 3.24, 4.51 and 6.37, respectively. The distribution ratio of Am(III) was measured as a function of various parameters such as concentration of nitric acid, TEHDGA, HA etc. The data were compared with those obtained in individual solvent systems namely 0.1 M TEHDGA/n-DD and HA/n-DD. Slope analysis of the extraction data indicated the synergic participation of both TEHDGA and HDEHP in the extraction of Am(III) at all acidities. However, antagonistic effect was observed at lower acidity when TEHDGA was mixed to PC88A or CYANEX-272 present inn-DD. Accordingly, a suitable mechanism has been proposed for the extraction of Am(III) at all acidities using these combined solvent formulation. Studies with fast reactor simulated high level liquid waste indicated that extraction of Am(III) was accompanied by co-extraction of lanthanides and unwanted metal ions such as Zr(IV), Mo(VI), Y(III) and Pd(II). However, addition of trans-1,2-diaminocyclohexane-N,N,N,N′-tetraaceticacid (CyDTA) reduced the extraction of unwanted metal ions. Batch extraction and stripping studies indicated the possibility of using 0.1 M TEHDGA+0.25 M HDEHP inn-dodecane for the single cycle separation of Am(III) from FR-SHLLW.

Electrolytic extraction of palladium from nitric acid and simulated high-level liquid waste

2009 ◽  
Vol 12 (1-3) ◽  
pp. 34-39 ◽  
Author(s):  
M. Jayakumar ◽  
K.A. Venkatesan ◽  
T.G. Srinivasan ◽  
P.R. Vasudeva Rao
Keyword(s):  
Nitric Acid ◽  
Liquid Waste ◽  
High Level Liquid Waste ◽  
Electrolytic Extraction ◽  
High Level
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