Plutonium chemical properties in NaCl–KCl and CaCl2 at 1073K

Lambertin, David; Ched'Homme, S.; Bourges, Gilles; Sanchez, Sylvie; Picard, Gauthier

doi:10.1016/j.jnucmat.2005.01.010

Cited by 19 publications

(24 citation statements)

References 13 publications

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“…In most of the studies, measurements have been made simply by visual determination of the immersion depth, 4,14,17,[22][23][24][25][26][27][28]32,33,39,42,[49][50][51][52][53]58 which has an error associated with capillary effects and wetting between the electrode and the salt at different temperatures. Several studies used wires encased in alumina or other insulating material tubes with a known apparent surface area.…”

Section: Resultsmentioning

confidence: 99%

Method Development for Quantitative Analysis of Actinides in Molten Salts

Tylka

Willit

Prakash

et al. 2015

J. Electrochem. Soc.

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This paper describes how electrochemical techniques have been used to develop a method for high-precision, real-time quantitative measurements of the concentration of actinides, present in in molten salts as actinide chlorides, for pyrochemical process monitoring applications. Possible reasons for discrepancies between reported measurements obtained with electrochemical techniques have been investigated and a combination of methods to improve their precision has been established. The combination of methods consists of selecting a suitable electroanalytical measurement technique, experimentally verifying assumptions used in its theoretical analysis, ensuring reproducible conditions at the electrode/electrolyte interface, and using an improved method to eliminate the need to know the electrode surface area. By following the developed procedures and refining both experimental techniques and data analysis methods, precise and reproducible measurements were obtained for U and Pu in LiCl/KCl eutectic at 773 K. Preliminary results showed that cyclic voltammetry, along with a method of standard area addition, are very promising tools for in situ quantitative measurements with a degree of precision comparable to destructive analysis techniques. Electrorefining is the main step in pyrochemical reprocessing. During this process, actinides are separated from the bulk of the fission product elements by electrochemical dissolution and electrotransport onto a solid or liquid cathode. The goal of the process is to maximize the separation and recovery of actinides from chlorinated fission products so that minimal amounts of actinides are lost to the process waste stream. [1][2][3][4][5] In addition to efficient actinide recovery, there is a need to address the safeguarding the recycle system. 5 Highprecision, real-time concentration measurements of actinides, present as actinide chlorides, in molten salts are required for process monitoring and control and could be used to support traditional material control and accountability techniques. Development of these measurements is essential to implement and operate a commercial fuel reprocessing facility. [6][7][8][9][10] Electrochemical techniques are well suited for in situ monitoring because they allow rapid, real-time measurements, are compatible with remote handling operations, and do not require the use of standards. Also, the equipment is not affected by the high radiation field present in a fuel processing operation.9,10 Unlike offline destructive analysis techniques, in situ methods do not require representative sample collection and preparation, and therefore avoid problems with sample contamination and degradation. In addition, analytical results can be received in a relatively short period (for example, less than 2 minutes).In an electrochemical cell, the measured potential (E), current (i), or charge (Q) is related to the quantity of the analyte in the solution; therefore, it can serve as an analytical signal for concentration measurements. 11,12 Depending on the applied...

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Section: Resultsmentioning

confidence: 99%

Method Development for Quantitative Analysis of Actinides in Molten Salts

Tylka

Willit

Prakash

et al. 2015

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…So, the cathodic peaks Ic and IIc are attributed respectively to the reduction of Pu(III) into Pu and the reduction of Na + into Na. The cathodic limit of equimolar NaCl-KCl solvent salt was previously determined and corresponds to E Na(I)/Na = −3.28 V (versus Cl 2 , 1 atm/Cl − ) [7,8]. The reduction potential of Na + (peak IIc) is more positive with Pu(III).…”

Section: Electrochemical Studies Of Plutonium In Eutectics Nacl-kcl-bmentioning

confidence: 99%

“…Another hypothesis is the presence of a complex anion in the melt, e.g. PuCl 6 3− that may change the acidity of the melt and probably the activity of NaCl at the interface. This potential increase results in plutonium sodium co-reduction at low Pu(III) activity.…”

Section: Electrochemical Studies Of Plutonium In Eutectics Nacl-kcl-bmentioning

confidence: 99%

“…The equilibrium potential, E eq , was approximated from the zero current intercepts of the reverse scans of the cyclic voltammetry [6,13] and led to the determination of the formal potential E * Pu(III)/Pu value by using the expression (1).…”

Section: Electrochemical Studies Of Plutonium In Eutectics Nacl-kcl-bmentioning

confidence: 99%

“…In the early studies, Pu(III)/Pu electrochemical system was investigated in the ternary NaCl-KCl-BaCl 2 [5] eutectic mixture by potentiometry. Later, Pu(III)/Pu system was studied in equimolar NaCl-KCl eutectic mixture and in pure CaCl 2 [6] by cyclic voltammetry. As solvent metal such as gallium could have potentialities for the recovery of plutonium from metallic scraps, the activity coefficient of plutonium dissolved in gallium was determined [7] using cyclic voltammetry and chronoamperometry.…”

Section: Introductionmentioning

confidence: 99%

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