Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2022

Kokubun, Yuji; Nakada, Akira; Seya, Natsumi; Koike, Yuko; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; Nagai, Shinji; et al.

JAEA-Review 2023-046, 164 Pages, 2024/03

JAEA-Review-2023-046.pdf:4.2MB

The Nuclear Fuel Cycle Engineering Laboratories conducts environmental radiation monitoring around the reprocessing plant in accordance with the "Safety Regulations for Reprocessing Plant of JAEA, Part IV: Environmental Monitoring". This report summarizes the results of environmental radiation monitoring conducted during the period from April 2022 to March 2023 and the results of dose calculations for the surrounding public due to the release of radioactive materials into the atmosphere and ocean. In the results of the above environmental radiation monitoring, many items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016), which occurred in March 2011. Also included as appendices are an overview of the environmental monitoring plan, an overview of measurement methods, measurement results and their changes over time, meteorological statistics results, radioactive waste release status, and an evaluation of the data which deviated of the normal range.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2020

Nakada, Akira; Nakano, Masanao; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Nemoto, Masashi; Tobita, Keiji; Futagawa, Kazuo; Yamada, Ryohei; Uchiyama, Rei; et al.

JAEA-Review 2021-062, 163 Pages, 2022/02

JAEA-Review-2021-062.pdf:2.87MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2020 to March 2021. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.

The Outline and present state of the Horonobe Underground Research Laboratory Project

Seya, Masami; Hatanaka, Koichiro; Fukushima, Tatsuo

Sato Kogyo Gijutsu Kenkyushoho, (31), p.49 - 56, 2006/11

Although the atomic energy is utilized as effective energy source, treatment and disposal of high-level radioactive waste are important issues to be solved. In Japan, the high-level radioactive waste is planned to be disposed off in deep underground and R&D programs for the treatment and the disposal of the high-level radioactive waste are underway by Japan Atomic Energy Agency(JAEA) and other research institutes. The Horonobe Underground Research Laboratory Project is one of the research projects of JAEA to establish the scientific and technical basis in sedimentary rocks at Horonobe-cho, Hokkaido. In this report we introduce the outline and current status of the Horonobe Underground Reasearch Laboratory Project.

Software development of MT3-D for site investigation, 6; Audio frequency MT3-D inversion study in Horonobe, Hokkaido

Yoshimura, Kimitaka*; Sakashita, Susumu*; Okubo, Shuichi*; Yamane, Kazunobu*; Seya, Masami

Shadan Hojin Butsuri Tansa Gakkai Dai-115-Kai (Heisei-18-Nendo Shuki) Gakujutsu Koenkai Rombunshu, p.209 - 212, 2006/10

3D MT inversion development has been conducted to solve issues in electromagnetic exploration in the radioactive waste disposal area. Radioactive Waste Management Funding and Research Center (RWMC) operated field work to confirm how the 3D inversion code worked in low resistivity geology at Horonobe area, Hokkaido in 2005 and applied the code to AMT data. Data suggests possibility to estimate salinity of groundwater in the area of lower resistivety than 1ohm-m.

Horonobe Underground Research Laboratory Project Investigation Program for the 2005 Fiscal Year (2005/2006)

Hama, Katsuhiro; Seya, Masami; Yamaguchi, Takehiro

JNC TN5510 2005-002, 29 Pages, 2005/05

JNC-TN5510-2005-002.pdf:8.27MB

The Horonobe Underground Research Laboratory Project is planned to extend over 20 years. Investigations will be conducted in three phases, namely from the surface (Phase 1), during construction of the underground facility (Phase 2) and in the underground facility itself (Phase 3). The 2005 fiscal year is the sixth (and final) year of the Phase 1 investigations and the first year of the Phase 2 investigations.Geophysical, geological, surface hydrogeological and borehole investigations are being carried out in order to develop techniques for exploring the geological environment. Based on the acquired data, geoscientific models are being constructed, revised and verified.As part of the development of techniques for monitoring the geological environment, long-term monitoring of groundwater pressures is ongoing in a borehole equipped in a previous investigation phase. Long-term monitoring systems are also being installed in the remaining boreholes at the site and measurements are ongoing. A remotely operated monitoring system (ACROSS) is also being installed and tested. Studies on the long-term stability of the geological environment include monitoring with seismographs, GPS and electromagnetic surveys. Engineering techniques for application in the deep underground environment will be developed during construction of the underground facilities. To provide input for detailed planning of the Phase 2 and 3 investigations, laboratory tests are being carried out on tunnel reinforcement materials. With a view to improving their reliability, safety assessment methods are being examined using field and laboratory data. Construction of the surface facilities, initiated in the previous fiscal year, is ongoing and the work on the public exhibition hall has now started. Environmental monitoring is ongoing, as is collaboration with domestic and overseas research institutes.