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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.
Sagawa, Hisashi; Koda, Nobuyuki; Hanawa, Nobuhiro; Maruo, Takeshi; Miyazawa, Masataka; Unesaki, Hironobu*; Nakagome, Yoshihiro*
IAEA-TECDOC-1593, p.121 - 128, 2008/06
In Japan, 1,712 of Research Reactor Spent Nuclear fuels (RRSNFs) have been transported to the US successfully since the receipt in accordance with the foreign research reactor spent nuclear fuel acceptance policy started in 1996. Especially, Japan Atomic Energy Agency (JAEA) carried out shipment to the US of eight times and of 1,283 fuel elements in total. This paper describes experiences of RRSNF transportation to the US in Japan.
Takeishi, Minoru; Hiyama, Yoshinori*; Mizutani, Tomoko; Watanabe, Hitoshi; Maruo, Yoshihiro
Proceedings of International Symposium on Technetium -Science and Utilization- (IST 2005), p.47 - 48, 2005/00
To investigate of Tc-99 release, large amount of liquid samples (8-litter) were used for the analysis, which was developed by JNC. The Tc-99 release in the liquid effluent from TRP during 1999-2000 were measured and the normalized release of Tc-99, which were normalized by annual energy generated (GWa) derived from the treated spent fuels, were compared with that of other radionuclides.
Maruo, Yoshihiro; Kawasaki, Satoru; Ono, Takayuki
JNC TN6440 2004-004, 49 Pages, 2004/07
JNC-TN6440-2004-004.pdf:0.89MB
This report is a result of [in 2004] environmental monitoring.
Sakamoto, Shigeyasu*; Ishimori, Yuu; Maruo, Yoshihiro
JNC TY6400 2004-001, 41 Pages, 2004/04
JNC-TY6400-2004-001.pdf:1.11MB
This report describes development of a radon standard source for establishing the traceability on radon concentration measurements.The radon that generates by babbling the radium solution was used for calibrations of radon measurement equipments. However, as for the radon source, which is reported here, the handling is easier because a solid phase radium source is used. Radioactivity of the radon, which is release in the vapor phase, was determined from a difference between the radioactivity of the radium and the radioactivity of the residual radon progeny in the source. Germanium detectors, which calibrated the detection efficiency with the gamma-ray reference sources, were used to those radioactivity measurements. As for the radioactivity of the radon, which is released from the radium source it was found that they are 988 Bqs. Sealing this source in the stainless steel container that is six liters in capacity, the standard radon source of density of 167.5 [Bq/l] was made.
Maruo, Yoshihiro; Ono, Takayuki
JNC TN6440 2004-002, 18 Pages, 2004/04
The environmental measurement result around Closed Uranium Mine.
Maruo, Yoshihiro; Ono, Takayuki; Kawasaki, Satoru
JNC TN6440 2003-003, 47 Pages, 2003/08
JNC-TN6440-2003-003.pdf:0.85MB
Environmental monitoring around Ningyo-toge has been carried out according to the environmental protection between JNC Ningyo-toge and the local governments. This report shows the results by the monitoring in 2003.
Shinohara, Kunihiko; ; Maruo, Yoshihiro; Momose, Takumaro; Takeishi, Minoru; Kobayashi, Hirohide;
JNC TN8440 2002-009, 99 Pages, 2002/08
This annual report is summary of the activities of Radiation Protection Division at JNC Tokai Works in fiscal year of 2001. This report consists of the introduction of the radiation control in working area of the reprocessing plant, the MOX fuel fabrication facilities and laboratories, the discharges control of these facilities, the personal dosimetry, the environmental monitoring, the control of radiation standards and calibration, the maintenance of radiation measurement instruments, the safety study, the technical support for outside organizations and other activities.
Kobayashi, Hirohide; ; ; Maruo, Yoshihiro; Miyabe, Kenjiro;
JNC TN8410 2002-006, 82 Pages, 2002/08
JNC-TN8410-2002-006.pdf:2.58MB
The stationary gaseous effluent monitor is equipment intended for continuously monitoring radioactivity in gaseous effluents released from the nuclear facilities. This monitor consists of sampling, detection and control assemblies. The sampling pump is a most integral part of the sampling assembly and required to be operated with an appropriate pressure to keep the continuous monitoring. However, in 1998, the failures of sampling pumps had successively occurred.This was due to the overload in pressure at the intake or the outlet. To prevent from the failures of sampling pumps, the overload characteristics and the mean time between failures (MTBF) were investigated. The following results were obtained. (1)The performance and tolerance tests with rapid increase of air pressure were carried out. The sampling pumps could withstand two or three times higher pressure than the regularly operating pressure during a few minutes. But, after that, the pump suddenly fell down by an over-current relay (OCR). (2)The MTBF were analyzed on the basis of the maintenance and repair records over a period from 1988 to 1998. The MTBF of a sampling pump were in the range from 7,600 to 35,500 hours. For a preventive maintenance, the consumption parts, such as a carbon blade and a bearing of rotor shaft, etc., should be replaced periodically.
Takasaki, Koji; Kurihara, Osamu; Tasaki, Takashi; Momose, Takumaro; Maruo, Yoshihiro; Shinohara, Kunihiko
THE 47TH ANNUAL CONFERENCE ON BIOASSAY,ANALYTICAL & ENVIRONMENTAL RADIOCHEMISTRY, 0 Pages, 2002/00
None
Maruo, Yoshihiro; ; Takeishi, Minoru; ; ; Takeyasu, Masanori;
JNC TN8440 2001-011, 146 Pages, 2001/06
JNC-TN8440-2001-011.pdf:2.98MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed since 1975, based on "Safety Regulations for the Tokai Reprocessing Plant, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitants due to the radioactivity discharged from the plant during April 2000 to March 2001. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.
Nakano, Masanao; Watanabe, Hitoshi; Maruo, Yoshihiro
Saikuru Kiko Giho, (11), p.129 - 135, 2001/06
None
; Watanabe, Hitoshi; Maruo, Yoshihiro; Shinohara, Kunihiko
Hoken Butsuri, 36(3), p.207 - 212, 2001/00
None
Kurihara, Osamu; Tsujimura, Norio; Takasaki, Koji; Momose, Takumaro; Maruo, Yoshihiro
Proceedings of iTRS International Symposium on Radiation Safety and Detection Technology (ISORD-1), 0 Pages, 2001/00
None
Maruo, Yoshihiro; ; ;
JNC TN8440 2001-001, 135 Pages, 2000/12
JNC-TN8440-2001-001.pdf:4.61MB
None
; ; Maruo, Yoshihiro
JNC TN8400 2000-031, 142 Pages, 2000/10
JNC-TN8400-2000-031.pdf:8.99MB
To evaluate the long-term environmental effect from the liquid radioactive effluent discharged to the ocean, the radioactivity diffusion model in global ocean and its computer program have been developed. This study consists of the method for the calculation of the velocity field for global ocean, movement and diffusion by particle chasing method, and the model validation by the simulation for the radioactive fallout from the atmospheric nuclear tests. The velocity field obtained by the diagnostic model represented real ocean very well. And it was confirmed that the result of the diffusion by random walk method was equal to that by the diffusion equation. Combined the current field obtained by the diagnosis model and random walk method, the simulation for the radioactive fallout from the atmospheric nuclear tests was carried out. As for 
Cs and 
Sr, the calculated value was agreed with the observed value. But as for 
Pu, the calculated value was not agreed because of the scavenging process. This result implied the necessity for adding Pu scavenging model to this diffusion code. The other side, the appropriate horizontal and vertical diffusion coefficients can be set up by the simulation with changing these coefficients.
Uezu, Yasuhiro; Nakano, Masanao; Fujita, Hiroki; Watanabe, Hitoshi; Maruo, Yoshihiro; Shinohara, Kunihiko
Proceedings of the International Workshop on Distribution and Speciation of Radionuclides in the Environment, p.354 - 357, 2000/00
Iodine-129 is an important radionuclide for environmental assessment, because it has a long half-life. A new analytical technique with Microwave Induced Plasma Mass Spectrometry (MIP-MS) was applied to the determination of iodine-129 (
I) in the environmental samples. Environmental samples contain a large amount of matrices elements. Therefore, the interference elements were eliminated by ashing at 1000
C, and iodine was trapped by activated charcoal and finally extracted by tetramethylammonium hydroxide (TMAH). I-129 in the soil sample was also analyzed by conventional method [neutron activation analysis (NAA)] and MIP-MS method. The analytical data by MIP-MS and NAA methods showed excellent agreement.
; Maruo, Yoshihiro; ; Shinohara, Kunihiko
PNC TN8460 92-001, 65 Pages, 1992/03
no abstracts in English
; Maruo, Yoshihiro; ; ; ; Kano, Yutaka; Sumiya, Shuichi
PNC TN8440 92-007, 161 Pages, 1992/03
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed since 1975, based on "Safety Regulations for the Tokai Reprocessing Plant. Chapter VII - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitants due to the radioactivity discharged from the plant during 1991. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.
