An Empirical model for the corrosion of stainless steel in BWR primary coolant

Uchida, Shunsuke*; Hanawa, Satoshi; Naito, Masanori*; Okada, Hidetoshi*; Lister, D. H.*

Corrosion Engineering, Science and Technology, 52(8), p.587 - 595, 2017/10

https://doi.org/10.1080/1478422X.2017.1357960

Based on the relationship among ECP, metal surface conditions, exposure time and other environmental conditions, a model to evaluate the ECP and corrosion rate of steel was developed by coupling a static electrochemical analysis and a dynamic oxide layer growth analysis. Major conclusion obtained on the model are as follows. The effect of HO and O concentrations on ECP were successfully explained as the effects of oxide layer growth. Hysteresis of ECP under changes in water chemistry conditions were successfully explained with the model. Decreases in ECP due to neutron exposure were explained well by radiation-induced diffusion in the oxide layers.

Electrochemical and spectroelectrochemical behaviour of Np(VI) ions in nitric acid solutions

Kim, S.-Y.; Asakura, Toshihide; Morita, Yasuji

Radiochimica Acta, 93(12), p.767 - 770, 2005/12

https://doi.org/10.1524/ract.2005.93.12.767

Electrochemical and spectroelectrochemical has been used to investigate the behaviour of Neptunium (VI) in concentration 1-8 M HNO solutions. The electrochemical reactions of Np(VI) ions were found to occur quasi-reversibly. The formal redox potentials (E) for Np(VI)/Np(V) couples were determined to be +0.906, +0.908, +0.909, +0.902, +0.896, +0.895, +0.888, and +0.884 V (vs. Ag/AgCl) for Np(VI) ions in 1, 2, 3, 4, 5, 6, 7, 8 M HNO solutions, respectively. The reduction processes of Np(VI) ions were followed spectroelectrochemically by using an optical transparent thin layer electrode cell. It was found that the absorption spectra measured at the applied potentials from +1.10 to +0.60 V versus Ag/AgCl reference electrode redox couple for Np(VI) in HNO solution have clear isosbestic points. These results indicate that the reduction product of Np(VI) is Np(V), which is considerably stable in HNO solution.

Electrochemical behavior and some thermodynamic properties of UCl and UCl dissolved in a LiCl-KCl eutectic melt

Kuznetsov, S. A.*; Hayashi, Hirokazu; Minato, Kazuo; Gaune-Escard, M.*

Journal of the Electrochemical Society, 152(4), p.C203 - C212, 2005/04

https://doi.org/10.1149/1.1864532

The electrochemical behavior of UCl and UCl dissolved in LiCl-KCl eutectic melt was studied at 723-823 K. Electroreduction of U(IV) in LiCl-KCl melt occurs via two successive steps involving transfer of one and three electrons. The diffusion coefficients of U(IV) and U(III) ions were determined by linear sweep voltammetry, chronopotentiometry, and chronoamperometry. The formal standard potential of EU(IV)/U(III), EU(IV)/U, and EU(III)/U were determined and some thermodynamic properties of UCl and UCl dissolved in LiCl-KCl eutectic melt were calculated. Influence of oxide ions on electrochemical behavior was also studied.

Electrochemical and spectroelectrochemical properties of neptunium(VI) ions in nitric acid solution

Kim, S.-Y.; Asakura, Toshihide; Morita, Yasuji; Uchiyama, Gunzo*; Ikeda, Yasuhisa*

Journal of Radioanalytical and Nuclear Chemistry, 262(2), p.311 - 315, 2004/11

https://doi.org/10.1023/B:JRNC.0000046758.48775.a0

no abstracts in English

Proceedings of the Workshop on Molten Salts Technology and Computer Simulation

Hayashi, Hirokazu; Minato, Kazuo

JAERI-Conf 2001-016, 181 Pages, 2001/12

JAERI-Conf-2001-016.pdf:11.72MB

Applications of molten salts technology to separations and syntheses of materials have been studied eagerly, which would develop new fields of materials science. Research Group for Actinides Science, Department of Materials Science, Japan Atomic Energy Research Institute (JAERI), together with Reprocessing and Recycle Technology Division, Atomic Energy Society of Japan, organized the Workshop on Molten Salts Technology and Computer Simulation at Tokai Research Establishment, JAERI on September 18, 2001. In the workshop eleven lectures were made and lively discussions were there on the bases and applications of the molten salts technology that covered the structure and basic properties of molten salts, the pyrochemical reprocessing technology and the relevant computer simulation.

Electrochemical behavior of neptunium in NaCl-2CsCl melt

Hayashi, Hirokazu; Minato, Kazuo*

no journal, , 

For a basis of the future nuclear fuel cycle, understanding the behavior of transuranium elements (TRU: Np, Pu, Am, Cm) is important. Experimental study on pyrochemical reprocessing of the fuels containing TRU is one of the important topics. But limited data are available on the behavior of TRU in some molten salts including NaCl-2CsCl melt which is considered to be used for pyrochemical reprocessing of MOX fuels in RIAR process. Only the electrochemical behavior of NpNp redox couple has been reported for Np ions in NaCl-2CsCl melt. In the present study, behavior of Np ions including the reduction of Np in NaCl-2CsCl melt was investigated. A typical cyclic voltammogram shows 2 groups of the signals corresponding to Np species. They were assigned to the redox reactions of Np/Np and NpNp, respectively by comparing with those observed in LiCl-KCl melt. The redox potentials and the diffusion coefficients obtained by various transient electrochemical techniques will be presented.