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.

NWAS: Developments for passive uranium assay system, 2

Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 10 Pages, 2013/10

A uranium mass assay system for 200-litter wastes drums applied by NDA method was developed and accumulated the data of the actual uranium bearing wastes drums. The system consists of the 16 pieces of Helium-3 proportional counters for neutron detection generated from U(,n) reaction or U spontaneous fissions with polyethylene moderation and a Germanium solid state detector for ray detection as to determine uranium enrichment. In previous report, some measurement experiences had been introduced briefly. After that satisfactory works had been continued and the uranium determination data of 850 drums had been accumulated approximately. On the other hand considerable problems on the system had been revealed technically or analytically. Such experiences are to be described precisely, in addition newly gained knowledge will be marshaled. Furthermore the next improvement plans are now prepared that will be capable of active neutrons assay for uranium bearing wastes drums.

Trial plan for advanced NDA system of uranium wastes; Introduction of active neutron method applied to NDA system

Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi; Haruyama, Mitsuo; Takase, Misao; Ozu, Akira; Kureta, Masatoshi

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-33-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2012/10

We developed uranium mass assay systems for 200-litter wastes drums applied passive neutron measurements by NDA method and applied for the actual wastes drums stored in URCP. The neutron measurement methodology of U(,n) reaction using He proportional counters delivered superior performance, however also included some problems that the neutron penetration rates are depend upon matrices or density of wastes drums, so it was difficult to determine uranium mass against "unknown objects". For the purpose of solving problems active neutron measurements appears promising, we are now challenging to improve our equipments, which are composed of neutron generator, polyethylene moderators and He proportional counters. The uranium mass are determined by counting secondary neutrons generated from nuclear fissions. Our preliminary simulations suggest good performances with higher sensitivities and accuracies. It is extremely expected to contribute in the fields of safeguards works.

Source development and novel applications of laser-driven plasma X-ray lasers in JAEA

Kawachi, Tetsuya; Hasegawa, Noboru; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Oba, Toshiyuki; Kaihori, Takeshi; Kishimoto, Maki; Ochi, Yoshihiro; Tanaka, Momoko; et al.

X-Ray Lasers 2010; Springer Proceedings in Physics, Vol.136, p.15 - 24, 2011/12

http://ci.nii.ac.jp/ncid/BB05543208

This paper reviews recent improvement in the source development of laser-driven X-ray lasers and the applications in the research fields of material science, laser processing, X-ray imaging, and radiation damage in biological cells. In the application for material science, we have firstly observed temporal correlation between the domain structures of ferro-electric substance under the Curie temperature. In the laser processing, new X-ray laser interferometer reveals us the nano-scale surface distortion of substance pumped by a femto-second optical pulse. In the X-ray diffraction image, we have taken several static images of micro-structure of samples: now we are trying to extend the objective to nano-scale dynamics using pump and probe method. In the radiation damage of biological cells, we observed double strand break in DNA using X-ray laser exposure; this results are compared with the case using incoherent several KeV X-ray exposure.

Decontamination performance evaluation of IF treatment technology and proof of IF production method

Ema, Akira; Kado, Kazumi; Suzuki, Kazuhiko*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(3), p.194 - 204, 2011/09

https://doi.org/10.3327/taesj.J10.026

This paper shows the investigation result of the reasonable IF treatment condition and the full-scale examination result by using this IF treatment condition. As a result, it could confirm 99% of the intermediate uranium fluoride in the cascade was removed for 60 days. Further, this paper shows the investigation result of the reasonable IF production condition and the full-scale examination result. As a result, it could be proved 3,355 kg-IF gas was produced.

Uranium refining and conversion plant decommissioning project

Zaima, Naoki; Morimoto, Yasuyuki; Sugitsue, Noritake; Kado, Kazumi

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.311 - 320, 2010/10

https://doi.org/10.1115/ICEM2010-40068

Picosecond snapshot of the speckles from ferroelectric BaTiO by means of X-ray lasers

Tai, R.; Namikawa, Kazumichi*; Kishimoto, Maki; Tanaka, Momoko; Sukegawa, Kota*; Hasegawa, Noboru; Kawachi, Tetsuya; Kado, Masataka; Lu, P.; Nagashima, Keisuke; et al.

Physical Review Letters, 89(25), p.257602_1 - 267602_4, 2002/12

https://doi.org/10.1103/PhysRevLett.89.257602

no abstracts in English

Proposal for the decontamination method of the radioactive substances by the chemical reaction, 2

Ema, Akira; Kado, Kazumi; Suzuki, Kazuhiko*

no journal, , 

In the nuclear industry, when the nuclear facilities are dismantled, the decontamination work of the radioactive substances is carried out. The selection of the decontamination method is a big problem because the enlargement of decontamination plant and increases of disposal cost is caused. In this study, we propose the new decontamination method of the uranium compounds by IF gas. In this presentation, we show the full-scale exam result and so on by using the actual uranium enrichment plant.

NWAS; Developments for passive uranium assay system

Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Kado, Kazumi

no journal, , 

We developed uranium mass assay systems for 200-litter wastes drums applied neutron and measurements by NDA method. The systems are composed of the 16 pieces of helium-3 proportional counters for neutron detection with 100 mm thicken polyethylene and a Ge-SSD for ray detection. The neutron measurement methodology is consist of U-234 (,n) reaction and measurement is applied by Ge-SSD. The extensive testing trials using the calibrated uranium sources with different enrichment and some kinds of matrices in drums were performed. By using this systems we tried to determine uranium mass in drums for the purpose of reduction MUF in URCP.

Recent progress on plasma X-ray laser and its application at JAEA

Kado, Masataka; Kawachi, Tetsuya; Ochi, Yoshihiro; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Sasaki, Akira; Hasegawa, Noboru; Kishimoto, Maki; Tanaka, Momoko; et al.

no journal, , 

Full coherent X-ray laser operating at 0.1 Hz are realized with originally developed high power laser system and double-target amplification scheme at JAEA. Utilizing the high spatial coherent several applications have been done recently such as study of temporal correlation of the domain fluctuation of BaTiO with X-ray speckle measurement and X-ray interferometric measurement of nano-scale dynamics of solid surface with X-ray interferometer. Irradiating the X-ray laser onto biological cells DNA radiation damages showed different features comparing ordinary X-ray sources. Recent progress of X-ray laser development at JAEA and its applications will be presented.