Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2023

Kokubun, Yuji; Hosomi, Kenji; Nagaoka, Mika; Seya, Natsumi; Inoue, Kazumi; Koike, Yuko; Uchiyama, Rei; Sasaki, Kazuki; Maehara, Yushi; Matsuo, Kazuki; et al.

JAEA-Review 2024-054, 168 Pages, 2025/03

JAEA-Review-2024-054.pdf:2.73MB

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 2023 to March 2024 and the results of dose calculations for the surrounding public due to the release of radioactive materials from the plant into the atmosphere and ocean. In the results of the above environmental radiation monitoring, several items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Holdings, Inc. on April 1, 2016), which occurred in March 2011. In addition, environmental monitoring plan, analysis and measurement methods, monitoring data and their chronological change, meteorological data after statistical processing, status of radioactive waste release and evaluation results of the data over the normal range are included as appendices.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2021

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

JAEA-Review 2022-078, 164 Pages, 2023/03

JAEA-Review-2022-078.pdf:2.64MB

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 2021 to March 2022. 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.

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.

Study on plutonium burner high temperature gas-cooled reactor in Japan; Introduction scenario, reactor safety and fabrication tests of the 3S-TRISO fuel

Ueta, Shohei; Mizuta, Naoki; Fukaya, Yuji; Goto, Minoru; Tachibana, Yukio; Honda, Masaki*; Saiki, Yohei*; Takahashi, Masashi*; Ohira, Koichi*; Nakano, Masaaki*; et al.

Nuclear Engineering and Design, 357, p.110419_1 - 110419_10, 2020/02

https://doi.org/10.1016/j.nucengdes.2019.110419

The concept of a plutonium (Pu) burner HTGR is proposed to incarnate highly-effective Pu utilization by its inherent safety features. The security and safety fuel (3S-TRISO fuel) employs the coated fuel particle with a fuel kernel made of plutonium dioxide (PuO) and yttria stabilized zirconia (YSZ) as an inert matrix. This paper presents feasibility study of Pu burner HTGR and R&D on the 3S-TRISO fuel.

Conceptual study of a plutonium burner high temperature gas-cooled reactor with high nuclear proliferation resistance

Goto, Minoru; Demachi, Kazuyuki*; Ueta, Shohei; Nakano, Masaaki*; Honda, Masaki*; Tachibana, Yukio; Inaba, Yoshitomo; Aihara, Jun; Fukaya, Yuji; Tsuji, Nobumasa*; et al.

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.507 - 513, 2015/09

A concept of a plutonium burner HTGR named as Clean Burn, which has a high nuclear proliferation resistance, had been proposed by Japan Atomic Energy Agency. In addition to the high nuclear proliferation resistance, in order to enhance the safety, we propose to introduce PuO-YSZ TRISO fuel with ZrC coating to the Clean Burn. In this study, we conduct fabrication tests aiming to establish the basic technologies for fabrication of PuO-YSZ TRISO fuel with ZrC coating. Additionally, we conduct a quantitative evaluation of the security for the safety, a design of the fuel and the reactor core, and a safety evaluation for the Clean Burn to confirm the feasibility. This study is conducted by The University of Tokyo, Japan Atomic Energy Agency, Fuji Electric Co., Ltd., and Nuclear Fuel Industries, Ltd. It was started in FY2014 and will be completed in FY2017, and the first year of the implementation was on schedule.

Irradiation performance of HTGR fuel in WWR-K research reactor

Ueta, Shohei; Shaimerdenov, A.*; Gizatulin, S.*; Chekushina, L.*; Honda, Masaki*; Takahashi, Masashi*; Kitagawa, Kenichi*; Chakrov, P.*; Sakaba, Nariaki

Proceedings of 7th International Topical Meeting on High Temperature Reactor Technology (HTR 2014) (USB Flash Drive), 7 Pages, 2014/10

A capsule irradiation test with the high temperature gas-cooled reactor (HTGR) fuel is being carried out using WWR-K research reactor in the Institute of Nuclear Physics of the Republic of Kazakhstan (INP) to attain 100 GWd/t-U of burnup under normal operating condition of a practical small-sized HTGR. This is the first HTGR fuel irradiation test for INP in Kazakhstan collaborated with Japan Atomic Energy Agency (JAEA) in frame of International Science and Technology Center (ISTC) project. In the test, TRISO coated fuel particle with low-enriched UO (less than 10% of U) is used, which was newly designed by JAEA to extend burnup up to 100 GWd/t-U comparing with that of the HTTR (33 GWd/t-U). Both TRISO and fuel compact as the irradiation test specimen were fabricated in basis of the HTTR fuel technology by Nuclear Fuel Industries, Ltd. in Japan. A helium-gas-swept capsule and a swept-gas sampling device installed in WWR-K were designed and constructed by INP. The irradiation test has been started in October 2012 and will be completed up to the end of February 2015. The irradiation test is in the progress up to 69 GWd/t of burnup, and integrity of new TRISO fuel has been confirmed. In addition, as predicted by the fuel design, fission gas release was observed due to additional failure of as-fabricated SiC-defective fuel.

Lanthanides (Eu and Gd)-Mssbauer spectroscopic study of defect-fluorite oxides coupled with new defect crystal chemistry model

Nakamura, Akio; Igawa, Naoki; Okamoto, Yoshihiro; Hinatsu, Yukio*; Wang, J.*; Takahashi, Masashi*; Takeda, Masuo*

Mssbauer Spectroscopy; Applications in Chemistry, Biology, and Nanotechnology, p.71 - 94, 2013/10

https://doi.org/10.1002/9781118714614.ch04

Uniaxial-pressure control of magnetic phase transitions in a frustrated magnet CuFeGaO ( = 0, 0.018)

Nakajima, Taro*; Mitsuda, Setsuo*; Takahashi, Keiichiro*; Yoshitomi, Keisuke*; Masuda, Kazuya*; Kaneko, Chikafumi*; Homma, Yuki*; Kobayashi, Satoru*; Kitazawa, Hideaki*; Kosaka, Masashi*; et al.

Journal of the Physical Society of Japan, 81(9), p.094710_1 - 094710_8, 2012/09

https://doi.org/10.1143/JPSJ.81.094710

Systematic measurement of lineal energy distributions for proton, He and Si ion beams over a wide energy range using a wall-less tissue equivalent proportional counter

Tsuda, Shuichi; Sato, Tatsuhiko; Takahashi, Fumiaki; Satoh, Daiki; Sasaki, Shinichi*; Namito, Yoshihito*; Iwase, Hiroshi*; Ban, Shuichi*; Takada, Masashi*

Journal of Radiation Research, 53(2), p.264 - 271, 2012/04

https://doi.org/10.1269/jrr.11135

Deposit energy distribution in microscopic site is basic information for understanding of biological effects of energetic heavy ion beams. To estimate RBE, lineal energy, , can be an appropriate physical index. In this work, a wall-less tissue equivalent proportional counter has been designed and used for the measurement of distributions, (), for 160 MeV H, 150 MeV/u He, 290 MeV/u C, 490 MeV/u Si and 500 MeV/u Ar. Data of () were also obtained in the wide range of LET. The dose-means of , , were compared with those calculated by the microdosimetric function of PHITS. It is found that the calculated () and agree fairly well with those measured. The values of are larger than those of LET less than 10 keV/m because of the discrete energy deposition by delta rays, while the relation is reversed above 10 keV/m. The results indicate that care should be taken in the difference between and LET when the values of RBE of energetic heavy ions are estimated.

Measurement of lineal energy distribution of heavy ion using wall-less tissue equivalent proportional counter

Tsuda, Shuichi; Sato, Tatsuhiko; Takahashi, Fumiaki; Satoh, Daiki; Sasaki, Shinichi*; Namito, Yoshihito*; Iwase, Hiroshi*; Ban, Shuichi*; Takada, Masashi*

KEK Proceedings 2011-8, p.100 - 108, 2011/12

http://www-lib.kek.jp/cgi-bin/kiss_prepri.v8?KN=201125008exit=8.

Deposit energy distribution in microscopic site is basic information for understanding of biological effects of energetic heavy ion beams. To estimate RBE, lineal energy, y, can be an appropriate physical index. In this work, a wall-less tissue equivalent proportional counter has been designed and used for the measurement of y distributions, , for 160 MeV H, 150 MeV/u He and 490 MeV/u Si ion beams. Data of and the dose-means of , , were compared with those calculated by the microdosimetric function of PHITS. It is found that the calculated and agree fairly well with those measured, as well as the already reported result of 290 MeV/u carbon beam.