Marking actinides for separation; Resonance-enhanced multiphoton charge transfer in actinide complexes

Matsuda, Shohei; Yokoyama, Keiichi; Yaita, Tsuyoshi; Kobayashi, Toru; Kaneta, Yui; Simonnet, M.; Sekiguchi, Tetsuhiro; Honda, Mitsunori; Shimojo, Kojiro; Doi, Reisuke; et al.

Science Advances (Internet), 8(20), p.eabn1991_1 - eabn1991_11, 2022/05

https://doi.org/10.1126/sciadv.abn1991

no abstracts in English

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 redox reactions of uranium(VI) complexes with multidentate ligands in dimethyl sulfoxide

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

Radiochimica Acta, 93(2), p.75 - 81, 2005/02

https://doi.org/10.1524/ract.93.2.75.59417

no abstracts in English

Neutron crystallographic study on rubredoxin from by BIX-3, a single-crystal diffractometer for biomacromolecules

Kurihara, Kazuo; Tanaka, Ichiro*; Chatake, Toshiyuki*; Adams, M. W. W.*; Jenney, F. E. Jr.*; Moiseeva, N.*; Bau, R.*; Niimura, Nobuo

Proceedings of the National Academy of Sciences of the United States of America, 101(31), p.11215 - 11220, 2004/08

https://doi.org/10.1073/pnas.0403807101

The structure of a rubredoxin (Rd) from , an organism that grows optimally at 100 C, was determined using the neutron single-crystal diffractometer for biological macromolecules (BIX-3) at the JRR-3 reactor of JAERI. Data were collected at room temperature up to a resolution of 1.5 , and the completeness of the data set was 81.9 %. The model contains 306 H atoms and 50 D atoms. A total of 37 hydration water molecules were identified. The model has been refined to final agreement factors of = 18.6 % and = 21.7 %. Several orientations of the O-D bonds of side chains, whose assignments from X-ray data were previously ambiguous, were clearly visible in the neutron structure. While most backbone N-H bonds had undergone some degree of H/D exchange throughout the molecule, five H atom positions still had distinctly negative (H) peaks. The neutron Fourier maps clearly showed the details of an extensive set of H bonds involving the ND terminus that may contribute to the unusual thermostability of this molecule.

Study on the stress corrosion cracking of zirconium in nuclear fuel reprocessing environment

Kato, Chiaki

JAERI-Research 2003-013, 143 Pages, 2003/08

JAERI-Research-2003-013.pdf:22.12MB

This study is investigation about stress corrosion cracking (SCC) of zirconium in nuclear fuel reprocessing. Chapter 1 is described background. Chapter 2 is explained experimental apparates. Chapter 3 is described the increased oxidization potential on the heat-transfer surface and suggested the initiation of SCC on a boiling heat-transfer surface. Chapter 4 is described that the SCC susceptibility increased with increasing nitric acid concentration and solution temperature on notched specimen by SSRT. In addition, the SCC susceptibility effected by the crystal anisotropy by the hot rolling direction and increased on a parallel face to the rolling direction. Chapter 5 is described that the SCC susceptibility increased in HAZ/base metal boundary in order to the preferential orientation of cleavage plane (0002). Chapter 6 is described that the increased oxidization potential on the heat-transfer surface is attributed to the reduction of nitrous acid concentration by the thermal decomposition on the surface and the removal of the decomposition product from solution by boiling bubbles.

Effect of neptunium ions on corrosion of stainless steel in nitric acid solution

Motooka, Takafumi; Kiuchi, Kiyoshi

Journal of Nuclear Science and Technology, 39(Suppl.3), p.367 - 370, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875485

A corrosion of a stainless steel in nitric acid solution containing Np has been studied. Using SUS304L stainless steel, corrosion tests in boiling neptunium nitrate solution were conducted under immersion and heat-transfer condition. By the weight loss measurement of stainless steel and the quantitative analysis of metallic ions dissolved in solution, the corrosion rates were obtained. The surface morphology was observed by scanning electron microscopy. The acceleration mechanism was investigated by electrochemistry and spectrophotometry. The corrosion rate was accelerated by addition of neptunium in nitric acid. Preferential intergranular corrosion was observed. The corrosion was enhanced under heat-transfer condition compared to immersion condition. In polarization measurements, the cathodic over-voltage was decreased; the cathodic current was increased by addition of Np. Spectrophotometric measurements showed that Np(V) oxidized to Np(VI) in boiling nitric acid. The corrosion acceleration mechanism in nitric acid solution containing Np suggested the re-oxidation of Np(V).

Neutron diffraction study on the structure of rubredoxin from it Pyrococcus furiosus

Kurihara, Kazuo; Tanaka, Ichiro; Adams, M. W. W.*; Jenney, F. E. Jr.*; Moiseeva, N.*; Bau, R.*; Niimura, Nobuo

Journal of the Physical Society of Japan, Vol.70, Supplement A, p.400 - 402, 2001/05

With the new single-crystal diffractometer BIX-3 at the JRR-3M reactor of JAERI, a single-crystal neutron diffraction analysis of the structure of the small protein rubredoxin from the hyperthermophile Pyrococcus furiosus is currently under way. Data were collected at room temperature up to a resolution of 1.5 intervals in and exposure times ranging from 60 to 77 minutes per frame. The completeness factor of the 1.5-. Included in the refinement are 301 hydrogen atoms and 40 deuterium atoms, and 29 water molecules were also identified. In the present model, the current value for R and R are 24.0 and 26.3 , respectively.

Modeling for migration of a redox-sensitive radionuclide in engineered barriers

*;

Nuclear Technology, 97, p.323 - 335, 1992/03

https://doi.org/10.13182/NT92-A34640

no abstracts in English

Neptunium migration involving oxidation-reduction reactions in engineered barriers

J.Ahn*;

Proc. of the 3rd Int. Symp. on Advanced Nuclear Energy Research; Global Environment and Nuclear Energy, 10 Pages, 1991/00

no abstracts in English

Development of chemical decontamination process for surface contaminated metal wastes using sulfuric acid-cerium(IV) Solution

Suwa, Takeshi; ; *

Dekomisshoningu Giho, (2), p.29 - 40, 1990/00

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_02.pdf

no abstracts in English