Development of a dissolution method for analyzing the elemental composition of fuel debris using sodium peroxide fusion technique

Nakamura, Satoshi; Ishii, Sho*; Kato, Hitoshi*; Ban, Yasutoshi; Hiruta, Kenta; Yoshida, Takuya; Uehara, Hiroyuki; Obata, Hiroki; Kimura, Yasuhiko; Takano, Masahide

Journal of Nuclear Science and Technology, 62(1), p.56 - 64, 2025/01

https://doi.org/10.1080/00223131.2024.2381553

A dissolution method for analyzing the elemental composition of fuel debris using the sodium peroxide (NaO) fusion technique has been developed. Herein, two different types of simulated debris materials (such as solid solution of (Zr,RE)O and molten core-concrete interaction products (MCCI)) were taken. At various temperatures, these debris materials were subsequently fused with NaO in crucibles, which are made of different materials, such as Ni, AlO, Fe, and Zr. Then, the fused samples are dissolved in nitric acid. Furthermore, the effects of the experimental conditions on the elemental composition analysis were evaluated using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), which suggested the use of a Ni crucible at 923 K as an optimum testing condition. The optimum testing condition was then applied to the demonstration tests with Three Mile Island unit-2 (TMI-2) debris in a shielded concrete cell, thereby achieving complete dissolution of the debris. The elemental composition of TMI-2 debris revealed by the proposed dissolution method has good reproducibility and has an insignificant contradiction in the mass balance of the sample. Therefore, this newly developed reproducible dissolution method can be effectively utilized in practical applications by dissolving fuel debris and estimating its elemental composition.

Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

https://shop.elsevier.com/books/sodium-cooled-fast-reactors/morishita/978-0-12-824076-2

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.

Depth profile and inventory of Cl in soil near the Fukushima Dai-ichi Nuclear Power Plant

Ota, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Honda, Maki*; Hosoya, Seiji*; Takano, Kenta*; et al.

JAEA-Conf 2018-002, p.99 - 102, 2019/02

https://doi.org/10.11484/jaea-conf-2018-002

no abstracts in English

Fabrication of Mach-Zehnder polimer waveguides by a direct-drawing technique using a focused proton beam

Miura, Kenta*; Sato, Takahiro; Ishii, Yasuyuki; Kiryu, Hiromu*; Ozawa, Yusuke*; Koka, Masashi; Takano, Katsuyoshi*; Okubo, Takeru; Yamazaki, Akiyoshi; Kada, Wataru; et al.

Key Engineering Materials, 534, p.158 - 161, 2013/00

https://doi.org/10.4028/www.scientific.net/KEM.534.158

Fabrication of polymer optical waveguides for the 1.5-m band using focused proton beam

Miura, Kenta*; Machida, Yuki*; Uehara, Masato*; Kiryu, Hiromu*; Ozawa, Yusuke*; Sasaki, Tomoyuki*; Hanaizumi, Osamu*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; et al.

Key Engineering Materials, 497, p.147 - 150, 2012/00

https://doi.org/10.4028/www.scientific.net/KEM.497.147

Development of oxygen-to-metal ratio of MOX pellet adjustment technology for the simplified MOX pellet fabrication method in the FaCT project

Takano, Tatsuo; Sudo, Katsuo; Takeuchi, Kentaro; Kihara, Yoshiyuki; Kato, Masato

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 7 Pages, 2011/12

Development of high burn-up fuels is essential to improve economy of the fast reactor fuel cycle. Increase of fuel burn-up is known to cause fuel-cladding chemical interaction (FCCI) and it mainly determines a lifetime of fuel pin. In order to extend a lifetime of fuel pin by mitigating FCCI, development of low oxygen-to-metal (O/M) MOX fuel has been carried out in plutonium fuel development center of JAEA. MOX fuel needs adjustment of the O/M ratio to less than 1.97 for high burn-up of 150 GWd/t. Therefore, O/M adjustment technology is one of the main subjects in development of a simplified MOX pellet fabrication method which has been advanced in the FaCT (Fast reactor Cycle Technology development) project. In previous work, changes in O/M ratio of MOX pellet during heat treatment were calculated from measurement results of oxygen potentials. On the basis of above calculation, heating tests were carried out to prepare low O/M ratio MOX pellets on a laboratory scale. The O/M ratios obtained in the heating tests were well consistent with calculation results. In the present study, a kilogram MOX scale furnace to adjust O/M ratio of MOX pellets for targeted value has been developed as next step.

Development of pressing machine with a die wall lubrication system for the simplified MOX pellet fabrication method in the FaCT project

Sudo, Katsuo; Takano, Tatsuo; Takeuchi, Kentaro; Kihara, Yoshiyuki; Kato, Masato

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12

Japan Atomic Energy Agency has been contracted to advance the Fast Reactor Cycle Technology Development project. As one part of the project, a simplified MOX pellet fabrication method has been developed for fast reactor fuels. In previous reports, feasibility of a simplified MOX pellet fabrication method was confirmed through hot and cold laboratory-scale experiments. The die wall lubrication pressing technology was one of the important technologies included in the development of the simplified MOX pellet fabrication method. In the work described here, a pressing machine with a die wall lubrication system was developed, and MOX pellet fabrication experiments were carried out on the kilogram MOX scale.

Hydrogen incorporation and gasochromic coloration of tungsten oxide films

Nagata, Shinji*; Inoue, Aichi; Yamamoto, Shunya; Tsuchiya, Bun*; Takano, Katsuyoshi; To, Kentaro*; Shikama, Tatsuo*

Journal of Alloys and Compounds, 446-447, p.558 - 561, 2007/10

https://doi.org/10.1016/j.jallcom.2007.01.039

The effect of the composition of non-stoichiometric WO films on the gasochromic coloration are investigated. The films are prepared by a reactive RF magnetron sputtering with varying oxygen partial pressure. To determine the quantitative composition of deposited films, Rutherford backscattering spectroscopy (RBS) and Elastic recoil detection (ERD) are employed. Gasochromic coloration of the films coated with Pd catalyst is examined by optical transmission in hydrogen gas. O/W atomic ratio of the films increases from 0.25 to 3.0 with increasing the oxygen partial pressure in the sputtering gas. H/W ratio increases up to 0.7 with increasing the O/W ration. As regards gasochromic coloration, the film with O/W atomic ratio of 3.0 shows superior coloration performance comparing with that of less than 3.0. Therefore, it is assumed that the good gasochromic coloration of tungsten oxide films is realized by near-stoichiometric WO. In addition, gasochromic coloration state, increasing of hydrogen concentration in WO films is observed. It indicates that gasochromic coloration of WO is relate to formation of HWO structure.

Interrelation between speckle images in X-ray diffraction spots of YBaCuO and its superconductive phase transition

Suzuki, Takuya*; Takano, Hidekazu*; Takeuchi, Akihisa*; Uesugi, Kentaro*; Asaoka, Hidehito; Suzuki, Yoshio*

Advances in X-Ray Chemical Analysis, Japan, 36, p.249 - 257, 2005/03

no abstracts in English

Fundamental study of fabrication of a light waveguide using proton beam writing

Miura, Kenta*; Sato, Takahiro; Koka, Masashi; Ishii, Yasuyuki; Takano, Katsuyoshi; Kada, Wataru; Yamazaki, Akiyoshi; Yokoyama, Akihito; Kamiya, Tomihiro; Uehara, Masato*; et al.

no journal, , 

no abstracts in English