Formation of MPd (M = Gd, Np) by the reaction of MN with Pd and chlorination of MPd using cadmium chloride

Hayashi, Hirokazu; Shibata, Hiroki; Sato, Takumi; Otobe, Haruyoshi

Journal of Radioanalytical and Nuclear Chemistry, 332(2), p.503 - 510, 2023/02

https://doi.org/10.1007/s10967-023-08760-4

The formation of MPd (M = Gd, Np) by the reaction of MN with Pd at 1323 K in Ar gas flow was observed. Cubic AuCu-type GdPd ( = 0.4081 0.0001 nm) and NpPd ( = 0.4081 0.0001 nm) were identified, respectively. The product obtained from the reaction of NpN with Pd contained additional phases including the hexagonal TiNi-type NpPd. Chlorination of the MPd (M = Gd, Np) samples was accomplished by the solid-state reaction using cadmium chloride at 673 K in a dynamic vacuum. Pd-rich solid solution phase saturated with Cd and an intermetallic compound PdCd were obtained as by-products of MCl formation.

A Simulation of radiolysis of chloride solutions containing ferrous ion

Hata, Kuniki; Inoue, Hiroyuki*

Journal of Nuclear Science and Technology, 56(9-10), p.842 - 850, 2019/09

https://doi.org/10.1080/00223131.2019.1585986

To investigate the effect of dissolved species from steels on the radiolysis processes of Cl, radiolysis simulations of solutions containing both Cl and Fe were carried out. The results showed that the generation of radiolytic products (HO, O and H) increased mainly by the addition of Fe, and a drop in the pH was caused by the hydrolysis of Fe. This pH drop enhanced the reactivity of Cl with OH, which induced additional generation of HO and O. These results show that low concentrations of Cl (1 10 mol/dm = 35ppm) in the presence of Fe could influence the generation of HO and O during water radiolysis. However, it is considered that these effects of Fe and low concentration of Cl on water radiolysis are less important for corrosion of steels due to the low concentrations of HO and O generated. The other process, such as dissolution of iron enhanced by FeOOH, might predominantly induce corrosion under the conditions of solutions with low concentrations of HO and O.

Formation and thermochemical properties of oxychlorides of niobium (Nb) and tantalum (Ta); Towards the gas-phase investigation of dubnium (Db) oxychloride

Chiera, N. M.; Sato, Tetsuya; Tomitsuka, Tomohiro; Asai, Masato; Suzuki, Hayato*; Tokoi, Katsuyuki; Toyoshima, Atsushi; Tsukada, Kazuaki; Nagame, Yuichiro

Inorganica Chimica Acta, 486, p.361 - 366, 2019/02

https://doi.org/10.1016/j.ica.2018.10.032

The formation of NbOCl and TaOCl and their adsorption behavior on quartz surfaces was explored by applying an isothermal gas-chromatographic method. Trace amounts of short-lived Nb and Ta isotopes were used. Adsorption enthalpy values () at zero surface coverage of -(NbOCl) = 102 4 kJ/mol and -(TaOCl) = 128 5 kJ/mol were determined by analyzing the chromatographic behavior of the Nb andTa complexes with a Monte-Carlo simulation method based on an adsorption-desorption kinetic model.By applying an empirical correlation, the experimental values were successively related to the macroscopic standard sublimation enthalpy, , as a measure of the volatility of each substance. The inferred sublimation enthalpies are in agreement with tabulated thermochemical values. Thus, the linear empirical correlation between and for metal-oxychlorides was updated with the inclusion of the present data. According to the predicted (DbOCl), a (DbOCl) value of 135 2 kJ/mol was extrapolated. The future accomplishment of comparative studies with DbOCl under the same experimental conditions will provide valuable information on the volatility trend in Group-5 elements, together with an indication on the magnitude of relativistic effects on the electronic structure of dubnium.

Effect of chloride concentration on corrosion behavior of carbon steel under -ray irradiation

Motooka, Takafumi; Ueno, Fumiyoshi

Zairyo To Kankyo, 64(6), p.220 - 223, 2015/06

http://doi.org/10.3323/jcorr.64.220

Corrosion behavior of carbon steel in chloride aqueous solutions under a low dose rate was investigated by corrosion test using chloride aqueous solutions with different chloride concentration at a dose rate of 500 Gy/h. The corrosion rate of carbon steel increased by the irradiation, and the corrosion rate had the maximum value at a certain chloride concentration. The oxidants produced by radiolysis of chloride aqueous solution enhanced the corrosion of carbon steel. The main oxidants were oxygen and hydrogen peroxide, and the diffusion process of oxidants controlled the corrosion of carbon steel under irradiation. There was a positive correlation between the dependence of corrosion rate and chloride concentration and the dependence of oxidant concentration and chloride concentration.

Molecular to ionic transition of BiCl in LiCl-KCl eutectic melt

Okamoto, Yoshihiro; Yaita, Tsuyoshi; Minato, Kazuo

Journal of Molecular Structure, 749(1-3), p.70 - 73, 2005/07

https://doi.org/10.1016/j.molstruc.2004.09.019

The local structures of molten BiCl and its mixtures in LiCl-KCl eutectic melt were investigated by X-ray absorption fine structure (XAFS) technique. The 1st Bi-Cl correlation in molten pure BiCl shows covalent nature, since the distance was almost the same as sum of covalent radii of Bi and Cl and the coordination number was almost 3. The similar property was observed also in the mixture of 75% BiCl with LiCl-KCl eutectic melt. Drastic change was detected in 25% BiCl mixture melt. The 1st Bi-Cl distance was sum of ionic radii in molten 25% BiCl melt. The results suggest that BiCl changes from molecular liquid to ionic by mixing with alkali chlorides.

Local structure of molten CdCl systems

Okamoto, Yoshihiro; Shiwaku, Hideaki; Yaita, Tsuyoshi; Suzuki, Shinichi; Minato, Kazuo; Tanida, Hajime*

Zeitschrift fr Naturforschung, A, 59a(11), p.819 - 824, 2004/11

The local structure of molten CdCl and CdCl-KCl mixture was investigated by high-temperature XAFS technique. The nearest Cd-Cl distance decreases by melting. Similarly, the coordination number decreases from 6 to 4. It suggests that there is (CdCl) tetrahedral complex ion in the melt. It is concluded that the local structure is kept also in the mixture melt, since the same XAFS result as the pure melt was obtained.

Density of molten terbium chloride

Sato, Tadashi; Okamoto, Yoshihiro

Zeitschrift fr Naturforschung, A, 58a(2-3), p.183 - 185, 2003/02

Density of molten terbium chloride is first measured by gamma-ray attenuation method as a function of temnperature ranging from 993 to 1213K. Empirical equation for the density of the melt is found to be .

X-ray absorption study of molten uranium chloride system

Okamoto, Yoshihiro; Akabori, Mitsuo; Ito, Akinori; Ogawa, Toru

Journal of Nuclear Science and Technology, 39(Suppl.3), p.638 - 641, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875549

We report local structural features of molten UCl with LiCl-KCl eutectic probed by the U L-edge XAFS(X-ray absorption fine structure). The XAFS measurements were performed in a transmission mode at the BL27B station of the Photon Factory(High Energy Accelerator Organization, Tsukuba, JAPAN). Sample prepared by chlorination of uranium hydride and then reduction with zinc powder was sealed in a quartz cell under reduced pressure. The nearest U-Cl distance and the coordination number of Cl around U ion were obtained by a curve fitting of the 1st shell XAFS function k(k). The pair potential in the U-Cl correlation was evaluated from XAFS simulation by combinational use of the MD and the FEFF8. In addition, valence state of uranium in the melt was evaluated by XANES(X-ray absorption near edge structure) spectra.

Structure of actinide compounds in solution and molten salt by utilizing XAFS and X-ray diffraction methods

Yaita, Tsuyoshi; Okamoto, Yoshihiro

Hoshako, 14(1), p.42 - 51, 2001/02

http://ci.nii.ac.jp/naid/10006656103

no abstracts in English

Investigation of molten salt fast breeder reactor

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JNC TN9400 2000-066, 52 Pages, 2000/06

JNC-TN9400-2000-066.pdf:1.82MB

Phase I of feasibility studies on commercialized fast reactor system is being peformed for two years from Japanese Fiscal Year 1999. In this report, results of the study on fluid fuel reactors (especialiy a molten salt fast breeder reactor concept) are described from the viewpoint of technical and economical concerns of the plant system design. ln JFY1999, we have started to investigate the fluid fuel reactors as alternative concepts of sodium cooled FBR systems with MOX fuel, and selected the unique concept of a molten chloride fast, breeder reactor, whose U-Pu fuel cycle can be related to both light water reactors and fast breeder reactors on the basis of present technical data and design experiences. We selected a preliminary composition of molten fuel and conceptual plant design through evaluation of technical and economical issues essential for the molten salt reactors and then compared them with reference design concepts of sodium cooled FBR systems under limited information on the molten chloride fast breeder reactors. The following results were obtained. (1)The molten chloride fast breeder reactors have inherent safety features in the core and plant performances, ad the fluid fuel is quite promising for cost reduction of the fuel fabrication and reprocessing. (2)On the other hand, the inventory of the molten chloride fuel becomes high and thermal conductivity of the coolant is inferior compared to those of sodium cooled FBR systems, then, the size of main components such as lHX's becomes larger and the amount of construction materials is seems to be increased. (3)Furthermore economical vessel and piping materials which contact with the molten chloride salts are required to be developed. From the results, it is concluded that further steps to investigate the molten chloride fast breeder reactor concepts are too early to be conducted.