Accumulation possibility of tritium released from the Fukushima Daiichi Nuclear Power Station in marine organisms

Sato, Yuhi*; Tani, Takashi*; Ikenoue, Tsubasa; Kawamura, Hideyuki; Omori, Yuko*

Environmental Science and Pollution Research, 8 Pages, 2026/00

https://doi.org/10.1007/s11356-026-37606-1

Tokyo Electric Power Company Holdings began the oceanic release of treated water from the Fukushima Daiichi Nuclear Power Station (FDNPS) in August 2023, in which radioactive materials were effectively removed using the Advanced Liquid Processing System (ALPS). The environmental behavior of tritium, accounting for almost all radioactivity in ALPS-treated water, is of critical scientific and social concern. The accumulation possibility of tritium in marine organisms under the release conditions of ALPS-treated water was reviewed to ensure the safety of fishery products collected off the Fukushima coast and prevent unfounded reputation damages to the products. First, previous findings from actual measurements and numerical model estimations of the distribution of tritium derived from ALPS-treated water in seawater off the Fukushima coast are summarized to discuss the impact of oceanic release on tritium levels in seawater. As a result, the impact is suggested to be highly limited, which is indistinguishable from a natural level except for within 200 km from FDNPS. Second, the accumulation possibility of organically bound tritium (OBT) in marine organisms, such as phytoplankton, seaweed, and fish, was assessed using previous findings obtained from experimental and numerical studies, resulting in far smaller OBT accumulations in those organisms compared to the food-chain guideline proposed by FAO/WHO. Finally, the risks of internal exposure through the ingestion of fishery products collected off the Fukushima coast are discussed and quantitatively explained to be minimal especially in comparison with the food-chain guideline. However, continuous environmental monitoring of the oceanic release of ALPS-treated water is considered essential.

Control of laser-driven shock wave utilizing hollow beam pattern

Miura, Eisuke*; Hironaka, Yoichiro*; Kurita, Takashi*; Shobu, Takahisa; Tominaga, Aki; Miyanishi, Kohei*; Ozaki, Narimasa*; Watari, Takeshi*; Shigemori, Keisuke*

SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 13(5), p.293 - 298, 2025/10

https://doi.org/10.18957/rr.13.5.293

no abstracts in English

Performance evaluation of floating seismic isolation system

Mori, Takashi*; Shimada, Takahiro*; Motegi, Haruki*; Kai, Satoru*; Otani, Akihito*; Yamamoto, Tomohiko; Yan, X.

Proceedings of the ASME 2025 Pressure Vessels & Piping Conference (PVP2025) (Internet), 9 Pages, 2025/07

https://doi.org/10.1115/PVP2025-153210

Measuring unit for synchronously collecting air dose rate and measurement position

Kawabata, Kuniaki; Imabuchi, Takashi; Shirasaki, Norihito*; Suzuki, Soichiro; Ito, Rintaro; Aoki, Yuto; Omori, Takazumi

ROBOMECH Journal (Internet), 11, p.11_1 - 11_11, 2024/09

https://doi.org/10.1186/s40648-024-00279-x

Intruder configurations in Ne at the transition into the island of inversion; Detailed structure study of Ne

Wang, H.*; Yasuda, Masahiro*; Kondo, Yosuke*; Nakamura, Takashi*; Tostevin, J. A.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Poves, A.*; Shimizu, Noritaka*; Yoshida, Kazuki; et al.

Physics Letters B, 843, p.138038_1 - 138038_9, 2023/08

https://doi.org/10.1016/j.physletb.2023.138038

Detailed -ray spectroscopy of the exotic neon isotope Ne has been performed using the one-neutron removal reaction from Ne. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N = 20 and N = 28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.

Experiment of floating seismic isolation system

Mori, Takashi*; Shimada, Takahiro*; Kai, Satoru*; Otani, Akihito*; Yamamoto, Tomohiko; Yan, X.

Proceedings of the ASME 2023 Pressure Vessels and Piping Conference (PVP 2023) (Internet), 8 Pages, 2023/07

https://doi.org/10.1115/PVP2023-102224

Present status of J-PARC MUSE

Shimomura, Koichiro*; Koda, Akihiro*; Pant, A. D.*; Natori, Hiroaki*; Fujimori, Hiroshi*; Umegaki, Izumi*; Nakamura, Jumpei*; Tampo, Motonobu*; Kawamura, Naritoshi*; Teshima, Natsuki*; et al.

Journal of Physics; Conference Series, 2462, p.012033_1 - 012033_5, 2023/03

https://doi.org/10.1088/1742-6596/2462/1/012033

Analysis of the radioactivity concentrations in radioactive waste generated from JRR-3, JRR-4 and JRTF facilities

Tobita, Minoru*; Konda, Miki; Omori, Takeshi*; Nabatame, Tsutomu*; Onizawa, Takashi*; Kurosawa, Katsuaki*; Haraga, Tomoko; Aono, Ryuji; Mitsukai, Akina; Tsuchida, Daiki; et al.

JAEA-Data/Code 2022-007, 40 Pages, 2022/11

JAEA-Data-Code-2022-007.pdf:1.99MB

Radioactive wastes generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried in the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes until the beginning of disposal. In order to contribute to this work, we collected and analyzed concrete, ash, ceramic and brick samples generated from JRR-3, JRR4 and JRTF facilities. In this report, we summarized the radioactivity concentrations of 24 radionuclides (H, C, Cl, Ca, Co, Ni, Sr, Nb, Tc, Ag, I, Cs, Ba, Eu, Eu, Ho, U, U, Pu, Pu, Pu, Am, Am, Cm) which were obtained from radiochemical analysis of the samples in fiscal years 2020-2021.

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.

PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

https://doi.org/10.1186/s40623-021-01486-1

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.