REDOX state analysis of platinoid elements in simulated high-level radioactive waste glass by synchrotron radiation based EXAFS

Okamoto, Yoshihiro; Shiwaku, Hideaki; Nakada, Masami; Komamine, Satoshi*; Ochi, Eiji*; Akabori, Mitsuo

Journal of Nuclear Materials, 471, p.110 - 115, 2016/02

https://doi.org/10.1016/j.jnucmat.2016.01.008

Extended X-ray Absorption Fine Structure (EXAFS) analyses were performed to evaluate REDOX (REDuction and OXidation) state of platinoid elements in simulated high-level nuclear waste glass samples prepared under different conditions of temperature and atmosphere. At first, EXAFS functions were compared with those of standard materials such as RuO. Then structural parameters were obtained from a curve fitting analysis. In addition, a fitting analysis used a linear combination of the two standard EXAFS functions of a given elements metal and oxide was applied to determine ratio of metal/oxide in the simulated glass. The redox state of Ru was successfully evaluated from the linear combination fitting results of EXAFS functions. The ratio of metal increased at more reducing atmosphere and at higher temperatures. Chemical form of rhodium oxide in the simulated glass samples was RhO unlike expected RhO. It can be estimated rhodium behaves according with ruthenium when the chemical form is oxide.

High-temperature X-ray imaging study of simulated high-level waste glass melt

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 81(7), p.543 - 546, 2013/07

https://doi.org/10.5796/electrochemistry.81.543

The molten state of simulated high-level waste glass and the behavior of ruthenium element in the melt were investigated by using synchrotron radiation based X-ray imaging technique. Melting, generating and moving of bubbles, condensation and sedimentation of ruthenium element were observed dynamically in continuous 12-bit gray-scale images from the CCD camera. X-ray intensity was obtained easily by digitizing gray-scale values in the image. The existence of ruthenium element is emphasized as a black color in the CCD image at X-ray energy higher than the Ru K-absorption edge. Position sensitive imaging X-ray absorption fine structure (XAFS) measurement was also performed to clarify the chemical state of ruthenium element in the melt.

Synchrotron radiation-based X-ray imaging study of ruthenium in simulated high-level waste glass

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Shiwaku, Hideaki; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(2), p.127 - 132, 2012/06

https://doi.org/10.3327/taesj.J11.031

Distribution and the chemical state of Ru element in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. In this technique, a direct X-ray CCD camera is used in place of an ion chamber. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the X-ray CCD camera. At first, we measured a test sample containing RuO and Ru metal powder. We successfully obtained information on the Ru distribution in the sample. In addition, the chemical state (oxide or metal ?) of each small Ru-rich spot was evaluated by the corresponding position sensitive XAFS spectrum. The imaging XAFS technique was applied to some simulated high-level waste glass samples. The Ru distribution of the glass sample and their chemical state were confirmed by image analyses. It can be seen that Ru element scattered in the glass sample exists as oxide RuO.

Evaluation of HLW glass dissolution/alteration kinetics by using micro-channel flow-through test method; Initial glass dissolution rate as a function of pH and temperature

Inagaki, Yaohiro*; Sakatani, Keiichi*; Yamamura, Yuki*; Mitsui, Seiichiro; Noshita, Kenji*; Miura, Yoshiyuki*; Kanehira, Norio*; Ochi, Eiji*; Mukunoki, Atsushi*; Chiba, Tamotsu*

Dai-7-Kai Saishori, Risaikuru Bukai Semina Tekisuto, p.136 - 137, 2011/01

Conventional static test methods are not appropriate to evaluate glass dissolution behavior at an arbitrarily-fixed condition due to compositional change of the solution with glass dissolution. In this study, we applied a newly-devised micro-channel flow-through test method to measurement of the initial dissolution rates of Japanese simulated waste glasses, JAEA-P0798 and JNFL-KMOC, at arbitrarily-fixed conditions and we evaluated temperature and pH dependence of glass dissolution. The results showed that the initial dissolution rate increased with temperature and had "V-shaped" pH dependence at each temperature.

None

; ; Ochi, Eiji*

PNC TJ4125 86-002, 107 Pages, 1986/11

PNC-TJ4125-86-002.pdf:10.81MB

None

Study on the noble metals sedimentation behavior in the melted glass

Morikawa, Yo; Miyauchi, Atsushi; Nakajima, Masayoshi; Oyama, Koichi; Yamashita, Teruo; Komamine, Satoshi*; Ochi, Eiji*

no journal, , 

no abstracts in English

Study on the sedimentation behavior of the noble metal particles in molten borosilicate glass

Oyama, Koichi; Morikawa, Yo; Miyauchi, Atsushi; Nakajima, Masayoshi; Yamashita, Teruo; Komamine, Satoshi*; Ochi, Eiji*

no journal, , 

no abstracts in English

Properties and behavior of Insoluble Residue in the fused glass, 5; Chemical analysis by XAFS technique

Nagayama, Sachiko; Okamoto, Yoshihiro; Shiwaku, Hideaki; Nakada, Masami; Akabori, Mitsuo; Kawashima, Hidenori*; Komamine, Satoshi*; Ochi, Eiji*

no journal, , 

no abstracts in English

Properties of insoluble residue generated at Rokkasho Reprocessing Plant, 1; Introduction

Minato, Kazuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Yoshioka, Masahiro*

no journal, , 

Characteristics of the fine produced during the reprocessing of the spent fuel in the Rokkasho Reprocessing Plant are inevitable data to understand the behavior of the fine in the glass melter. It is also necessary to obtain the characteristic data of the fine to judge the validity of vitrification tests with simulated fine in KMOC facility. The property measurements and chemical reaction tests with simulated fine are valuable to obtain fundamental data that is necessary for the development of a new type of glass melter. With these objectives, the fine was transported from the Rokkasho Reprocessing Plant to the Tokai Research Center of the Japan Atomic Energy Agency and the fine and simulated fine were characterized.

Influence of long-term melting on the noble metals shape and glass viscosity, 2

Oyama, Koichi; Morikawa, Yo; Miyauchi, Atsushi; Nakajima, Masayoshi; Yamashita, Teruo; Komamine, Satoshi*; Ochi, Eiji*

no journal, , 

no abstracts in English