Compliance measures at the Radioactive Waste Treatment Facilities at the Nuclear Science Research Institute; Aseismic reinforcement of the Radioactive Waste Treatment Facility No. 3, Waste Size Reduction and Storage Facility, and Waste Volume Reduction Facility

Iketani, Shotaro; Suzuki, Takeshi; Yokobori, Tomohiko; Sugawara, Satoshi; Yokota, Akira; Kikuchi, Genta; Muraguchi, Yoshinori; Kitahara, Masaru; Seya, Manato; Kurosawa, Tsuyoshi; et al.

JAEA-Technology 2025-001, 169 Pages, 2025/08

JAEA-Technology-2025-001.pdf:14.22MB

The radioactive waste treatment facilities at the Nuclear Science Research Institute includes the Radioactive Waste Treatment Facility No. 3, Waste Size Reduction and Storage Facility, and Waste Volume Reduction Facility. These three facilities come under the purview of the Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors, and are included under Class C of the act based on the seismic requirements specified in the Act. We assessed the seismic capacity of these three radioactive waste treatment facilities based on the current Building Standards Act, to verify whether they comply with the new regulatory requirements enforced by the Nuclear Regulation Authority (NRA) in the aftermath of the 2011 nuclear accident at the Fukushima Daiichi Nuclear Power Station operated by the Tokyo Electric Power Company. We found that the allowable stress of a few structural members used in the construction of the facilities did not meet the regulatory requirements. After studying the approval granted by the NRA for the construction plans, including the design and construction methods (design and construction plans) of the three facilities on March 5, 2021, we made aseismic reinforcement at these facilities between 2021 and 2022. This report presents an overview of the seismic design of these facilities and an outline of the aseismic reinforcement conducted, management system existing, safety measures adopted, and the preoperational inspections conducted at these facilities.

Oxygen reduction activity and interfacial structures of LaSrCoO at initial electrochemical process in an alkaline solution

Matsuzaki, Akira*; Hirayama, Masaaki*; Oguchi, Shoya*; Komo, Mamoru*; Ikezawa, Atsunori*; Suzuki, Kota*; Tamura, Kazuhisa; Arai, Hajime*; Kanno, Ryoji*

Electrochemistry (Internet), 90(10), p.107001_1 - 107001_8, 2022/10

https://doi.org/10.5796/electrochemistry.22-00079

Oxygen reduction and evolution reactions (ORR and OER) of perovskite-type LaSrCoO were characterized using two-dimensional model electrodes with different reaction planes. Synthesized by pulsed laser deposition, these thin and flat electrodes can reveal the reaction plane dependence of the ORR activity. From steady-state polarization measurements in KOH (aq.), the ORR activity was the highest on the (001) film during the first ORR/OER cycle, and it decreased significantly during the second cycle. In-situ synchrotron X-ray diffraction clarified crystal structure changes in the bulk and surface regions of LaSrCoO, and these changes are associated with forming oxygen defects during the initial electrochemical process. Furthermore, the LaSrCoO surface partially decomposed upon reacting. Therefore, the interfacial structures formed in the electrochemical reaction field is important for enhancing ORR and OER activities.

Study on identification of materials in fuel debris and waste by neutron induced gamma ray spectroscopy

Nauchi, Yasushi*; Nomi, Takayoshi; Suzuki, Risa; Kosuge, Yoshihiro*; Shiba, Tomooki; Takada, Akira*; Kaburagi, Masaaki; Okumura, Keisuke

Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR2022) (Internet), 4 Pages, 2022/10

Depth profile analysis of multi-layer laminated thin film interface by spatiotemporal angle-resolved APXPS method

Toyoda, Satoshi*; Yoshimura, Masashi*; Sumida, Hirosuke*; Mineoi, Susumu*; Machida, Masatake*; Yoshigoe, Akitaka; Yoshikawa, Akira*; Suzuki, Satoru*; Yokoyama, Kazushi*

Hoshako, 35(3), p.200 - 206, 2022/05

The present status of spatiotemporal depth profiling analysis of the multilayer stacked film interface based on Ambient Pressure X-ray Photoelectron Spectroscopy (APXPS) is presented. To begin with, depth profiles of the multilayer stacked film interfaces have been achieved by time-division Near Ambient Pressure Hard X-ray Angle-Resolved PhotoEmission Spectroscopy data. We then have promoted our methods to quickly perform peak fittings and depth profiling from time-division angle resolved AP-XPS data including spatial resolution, which enables us to realize spatiotemporal depth profiles of the interfaces under reaction conditions such as oxidation and reduction. In addition, it is found that the traditional maximum entropy method (MEM) combined with Jackknife averaging of sparse modeling is effective to perform dynamic measurement of depth profiles with high precision.

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

https://doi.org/10.1038/s41550-020-01271-2

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Development and operation of an electrostatic time-of-flight detector for the Rare RI storage Ring

Nagae, Daisuke*; Abe, Yasushi*; Okada, Shunsuke*; Omika, Shuichiro*; Wakayama, Kiyoshi*; Hosoi, Shun*; Suzuki, Shinji*; Moriguchi, Tetsuro*; Amano, Masamichi*; Kamioka, Daiki*; et al.

Nuclear Instruments and Methods in Physics Research A, 986, p.164713_1 - 164713_7, 2021/01

https://doi.org/10.1016/j.nima.2020.164713

Intercomparison of numerical atmospheric dispersion prediction models for emergency response to emissions of radionuclides with limited source information in the Fukushima Dai-ichi Nuclear Power Plant accident

Iwasaki, Toshiki*; Sekiyama, Tsuyoshi*; Nakajima, Teruyuki*; Watanabe, Akira*; Suzuki, Yasushi*; Kondo, Hiroaki*; Morino, Yu*; Terada, Hiroaki; Nagai, Haruyasu; Takigawa, Masayuki*; et al.

Atmospheric Environment, 214, p.116830_1 - 116830_11, 2019/10

https://doi.org/10.1016/j.atmosenv.2019.116830

The utilization of numerical atmospheric dispersion prediction (NDP) models for accidental discharge of radioactive substances was recommended by a working group of the Meteorological Society of Japan. This paper is to validate the recommendation through NDP model intercomparison in the accidental release from the Fukushima Dai-ichi Nuclear Power Plant in 2011. Emission intensity is assumed to be constant during the whole forecast period for the worst-case scenario unless time sequence of emission is available. We expect to utilize forecasts of surface air contaminations for preventions of inhalations of radioactive substances, and column-integrated amounts for mitigation of radiation exposure associated with wet deposition. Although NDP forecasts have ensemble spread, they commonly figure out relative risk in space and time. They are of great benefit to disseminating effective warnings to public without failure. The multi-model ensemble technique may be effective to improve the reliability.

A New approach for measuring the muon anomalous magnetic moment and electric dipole moment

Abe, Mitsushi*; Bae, S.*; Beer, G.*; Bunce, G.*; Choi, H.*; Choi, S.*; Chung, M.*; da Silva, W.*; Eidelman, S.*; Finger, M.*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(5), p.053C02_1 - 053C02_22, 2019/05

https://doi.org/10.1093/ptep/ptz030

This paper introduces a new approach to measure the muon magnetic moment anomaly and the muon electric dipole moment (EDM) at the J-PARC muon facility. The goal of our experiment is to measure and using an independent method with a factor of 10 lower muon momentum, and a factor of 20 smaller diameter storage-ring solenoid compared with previous and ongoing muon g-2 experiments with unprecedented quality of the storage magnetic field. Additional significant differences from the present experimental method include a factor of 1000 smaller transverse emittance of the muon beam (reaccelerated thermal muon beam), its efficient vertical injection into the solenoid, and tracking each decay positron from muon decay to obtain its momentum vector. The precision goal for is a statistical uncertainty of 450 parts per billion (ppb), similar to the present experimental uncertainty, and a systematic uncertainty less than 70 ppb. The goal for EDM is a sensitivity of ecm.

Prediction of the drying behavior of debris in Fukushima Daiichi Nuclear Power Station for dry storage

Nakayoshi, Akira; Suzuki, Seiya; Okamura, Nobuo; Watanabe, Masayuki; Koizumi, Kenji

Journal of Nuclear Science and Technology, 55(10), p.1119 - 1129, 2018/10

https://doi.org/10.1080/00223131.2018.1480429

Shell evolution beyond =28 and =50; Spectroscopy of Zn

Shand, C. M.*; Podolyk, Zs.*; Grska, M.*; Doornenbal, P.*; Obertelli, A.*; Nowacki, F.*; Otsuka, T.*; Sieja, K.*; Tostevin, J. A.*; Tsunoda, T.*; et al.

Physics Letters B, 773, p.492 - 497, 2017/10

https://doi.org/10.1016/j.physletb.2017.09.001