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.

Enhancement of IR-light emission from -FeSi nanocrystals by Cu doping

Hirata, Tomoaki*; Kagawa, Seiya*; Nagatsuyu, Tomohiro*; Shibahara, Kohei*; Iwamoto, Ryotaro*; Kawakubo, Yuki*; Noguchi, Masaya*; Mizuki, Tatsuya*; Narumi, Kazumasa; Sakai, Seiji; et al.

no journal, , 

no abstracts in English

Application of rapid in-vitro bioassay for determining internal contamination of radiation workers; To prepare for decommissioning in Fukushima Daiichi NPS

Ono, Masako*; Noguchi, Mizuki*; Nagaoka, Mika; Maehara, Yushi; Fujita, Hiroki

no journal, , 

On March 11, 2011, a tremendous earthquake of a 9.0 magnitude occurred undersea off the northeastern coast, triggering a massive tsunami. Flooding from the tsunami caused the loss of core cooling functions, which led to the evaporation of water in the reactor pressure vessels of Units 1-3 at the Fukushima Daiichi Nuclear Power Station (FDNPS), resulting in an accident that damaged the reactor cores. After the accident, the decommissioning work is being carried out step by step, and it will now be entering the stage of taking on challenges in uncharted territory, on the way to full-scale decommissioning including retrieval of fuel debris. Radiation workers in decommissioning project who enters reactor buildings should conduct various kinds of tasks in working environment with relatively high concentration of radionuclides such as Strontium-90, Actinides, etc., is constantly present. Even if the workers wear appropriate protective equipment, intakes of radionuclides under unforeseen circumstances may result in internal exposure. Measurement of radioactive materials taken into the body in the event of an incident can be conducted by in-vivo bioassay using WBC and lung monitors, and in-vitro bioassay using analysis of feces and urine. In FDNPS, all workers who enter the controlled area are subjected to routine individual monitoring of internal exposure by WBC (for screening purposes). For alpha-emitting radionuclides such as actinides and beta-emitting radionuclides such as Strontium-90, in-vitro bioassay measurements are generally used. In case of an internal exposure event, it is necessary to establish a rapid bioassay for judgment of medical treatment and for information collections to develop a plan of action. This presentation will provide an overview of the decommissioning work at FDNPS and application of a rapid bioassay method for mixed nuclides of Pu, Am, Cm, U, and Sr.