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.

Ferroaxial transitions in glaserite-type NaBa(PO) ( = Mg, Mn, Co, and Ni)

Kajita, Yoichi*; Nagai, Takayuki*; Yamagishi, Shigetada*; Kimura, Kenta*; Hagihara, Masato; Kimura, Tsuyoshi*

Chemistry of Materials, 36(15), p.7451 - 7458, 2024/08

https://doi.org/10.1021/acs.chemmater.4c01406

Ferroelectricity induced by a combination of crystallographic chirality and axial vector

Nagai, Takayuki*; Hagihara, Masato; Yokoi, Rie*; Moriwake, Hiroki*; Kimura, Tsuyoshi*

Journal of the American Chemical Society, 146(33), p.23348 - 23355, 2024/08

https://doi.org/10.1021/jacs.4c06283

High-temperature atomic diffusion and specific heat in quasicrystals

Nagai, Yuki; Iwasaki, Yutaka*; Kitahara, Koichi*; Takagiwa, Yoshiki*; Kimura, Kaoru*; Shiga, Motoyuki

Physical Review Letters, 132(19), p.196301_1 - 196301_6, 2024/05

https://doi.org/10.1103/PhysRevLett.132.196301

A quasicrystal is an ordered but non-periodic structure understood as a projection from a higher dimensional periodic structure. An anomalous increase in heat capacity at high temperatures has been discussed for over two decades as a manifestation of a hidden high dimensionality of quasicrystals. A theoretical study of the heat capacity of realistic quasicrystals or their approximants has yet to be conducted because of the huge computational complexity. To bridge this gap between experiment and theory, we show experiments and cutting-edge machine-learning molecular simulations on the same material, an Al-Pd-Ru quasicrystal, and its approximants. We show that at high temperatures, aluminum atoms diffuse with discontinuous-like jumps, and the diffusion paths of the aluminum can be understood in terms of jumps corresponding to hyperatomic fluctuations in six-dimensional space.

Measurements of the neutron total and capture cross sections and derivation of the resonance parameters of Ta

Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Rovira Leveroni, G.; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto

Nuclear Science and Engineering, 198(4), p.786 - 803, 2024/04

https://doi.org/10.1080/00295639.2023.2227826

Conceptual study of Post Irradiation Examination (PIE) Facility at J-PARC

Saito, Shigeru; Meigo, Shinichiro; Makimura, Shunsuke*; Hirano, Yukinori*; Tsutsumi, Kazuyoshi*; Maekawa, Fujio

JAEA-Technology 2023-025, 48 Pages, 2024/03

JAEA-Technology-2023-025.pdf:3.11MB

JAEA has been developing Accelerator-Driven Systems (ADS) for research and development of nuclear transmutation using accelerators in order to reduce the volume and hazardousness of high-level radioactive waste generated by nuclear power plants. In order to prepare the material irradiation database necessary for the design of ADS and to study the irradiation effects in Lead-Bismuth Eutectic (LBE) alloys, a proton irradiation facility is under consideration at J-PARC. In this proton irradiation facility, 250 kW proton beams will be injected into the LBE spallation target, and irradiation tests under LBE flow will be performed for candidate structural materials for ADS. Furthermore, semiconductor soft-error tests, medical RI production, and proton beam applications will be performed. Among these, Post Irradiation Examination (PIE) of irradiated samples and RI separation and purification will be carried out in the PIE facility to be constructed near the proton irradiation facility. In this PIE facility, PIE of the equipment and samples irradiated in other facilities in J-PARC will also be performed. This report describes the conceptual study of the PIE facility, including the items to be tested, the test flow, the facilities, the test equipment, etc., and the proposed layout of the facility.

Quantum critical behavior of the hyperkagome magnet MnCoSi

Yamauchi, Hiroki; Sari, D. P.*; Yasui, Yukio*; Sakakura, Terutoshi*; Kimura, Hiroyuki*; Nakao, Akiko*; Ohara, Takashi; Honda, Takashi*; Kodama, Katsuaki; Igawa, Naoki; et al.

Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02

https://doi.org/10.1103/PhysRevResearch.6.013144

Deformation-induced martensitic transformation at tensile and compressive deformations of bainitic steels with different carbon contents

Ueji, Rintaro*; Gong, W.; Harjo, S.; Kawasaki, Takuro; Shibata, Akinobu*; Kimura, Yuji*; Inoue, Tadanobu*; Tsuchida, Noriyuki*

ISIJ International, 64(2), p.459 - 465, 2024/01

https://doi.org/10.2355/isijinternational.ISIJINT-2023-253

Measurements of neutron total and capture cross sections of La and evaluation of resonance parameters

Endo, Shunsuke; Kawamura, Shiori*; Okudaira, Takuya*; Yoshikawa, Hiromoto*; Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki

European Physical Journal A, 59(12), p.288_1 - 288_12, 2023/12

https://doi.org/10.1140/epja/s10050-023-01203-4

no abstracts in English

Report on the 35th Meeting of Working Party on International Nuclear Data Evaluation Co-operation (WPEC)

Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Tada, Kenichi; Yokoyama, Kenji

Kaku Deta Nyusu (Internet), (136), 6 Pages, 2023/10

http://www.aesj.or.jp/~ndd/ndnews/pdf136/No136-01.pdf

no abstracts in English