Hato, Shinji*; Kinase, Sakae
Nippon Genshiryoku Gakkai Wabun Rombunshi, 15(3), p.146 - 150, 2016/09
Kameo, Yutaka; Fujiwara, Asako; Watanabe, Koichi; Kono, Nobuaki; Nakashima, Mikio
Nippon Genshiryoku Gakkai Wabun Rombunshi, 4(3), p.187 - 193, 2005/09
no abstracts in English
Ueno, Takashi; Amano, Hikaru
JAERI-Data/Code 2003-004, 49 Pages, 2003/03
This report presents the data of deposition of radionuclides (Sep. 1993-March 2001) and stable elements (Sep.1993-Oct.1995) in Tokai-mura. To evaluate the migration of radionuclides and stable elements migration from the atmosphere to the ground surface, atmospheric deposition samples were collected from 1993 to 2001 with three basins (distance to grand surface were 1.5m, 4m, 10m) set up in the enclosure of JAERI in Tokai-mura, Ibaraki-ken, Japan. Monthly samples were evaporated to dryness to obtain residual samples and measured with a well type Ge detector for 7Be, 40K, 137Cs and 210Pb. According to the analysis of radioactivity, clear seasonal variations with spring peaks of deposition weight (dry) and deposition amounts of all objective radionuclides were found. Correlation analysis of deposition data also showed that these radionuclides can be divided into two groups. A part of dried sample was irradiated to reactor neutrons at JRR-4 for determination of stable element's deposition.
Yasuda, Kenichiro; Sakurai, Satoshi; Gunji, Hideho; Usuda, Shigekazu
Journal of Nuclear Science and Technology, 39(Suppl.3), p.552 - 555, 2002/11
In order to contribute to the strengthened safeguards system based on the Program 93+2 of the IAEA, Japan Atomic Energy Research Institute (JAERI) constructed the CLEAR facility (Clean Laboratory for Environmental Analysis and Research) and is developing analytical technology for ultra trace amounts of nuclear materials in environmental samples. To avoid cross-contamination among the samples and contamination of the clean rooms, radioactive materials in the samples to be introduced into the CLEAR facility will be limited to a certain amount. For this purpose the authors have examined the feasibility of Imaging-plate method, which is a kind of autoradiography and is suitable for determination on distribution of low-level radioactivity in the samples. Preliminary examination with -ray (K-40), the linearity was obtained in the range of 0.01 - 0.2 Bq. The experiments with -ray (Sm-147) suggested the detection limit of 0.01 Bq, which was equivalent to 2 g of natural uranium. At the presentation, the results on actual environmental samples will be reported.
Kitatsuji, Yoshihiro; Aoyagi, Hisao; Kimura, Takaumi; Yoshida, Zenko; Kudo, Hiroshi*; Kihara, Sorin*
Journal of Nuclear Science and Technology, 39(Suppl.3), p.259 - 262, 2002/11
Controlled-potential electrolysis (CPE) method for the transfer of an ion at the interface of two immiscible electrolyte solutions has been developed. The CPE method was applied to the transfer of actinide ions such as UO and Am between aqueous (W) and nitrobenzene (NB) solutions. The transfer of actinide ions from W to NB facilitated by bis(diphenyl-phosphoryl)methane (BDPPM) was studied, and it was found that CPE was successfully applied to the electrolytic separation of U(VI) and Am(III) from W to NB containing BDPPM.
Motoki, Ryozo; Nemoto, Masahiro*
JAERI-Tech 2002-030, 46 Pages, 2002/03
no abstracts in English
JNC-TN8440 2001-018, 50 Pages, 2001/12
On September 30 at around 10:35 AM, criticality accident occurred at the JCO's conversion building in Tokai-mura. Since criticality accident had not been anticipated, neither devices for termination of criticality accident nor neutron detectors were available. Immediately after the information of the accident, our emergency staff(Japan Nuclear cycle development institute staff) went to JCO site, to measure the intensity of neutrons and gammas. There were four main tasks, first one was to measure the radiation intensity, second one was to terminate the criticality accident, third one is to alert the residents surrounding the JCO site, fourth one is to evacuate the employees in the site. These tasks were successfully performed until October 1. This paper describes about how these operations were performed by the relevant staffs.
Shinohara, Kunihiko; Takeishi, Minoru; ; ; Mizutani, Tomoko
JNC-TN8440 2001-019, 141 Pages, 2001/11
This report was written about the effluent control in JNC Tokai Works from 1 April 2000 to 31 March 2001. In this period, the quantities and concentrations of retroactivities in liquid waste from Tokai Works were under the discharge limits of "Safety Regulations for the Tokai Reprocessing Plant", "Safety Regulations for the Tokai Reprocessing Plant" and regulations of government.
Maruo, Yoshihiro; ; Takeishi, Minoru; ; ; Takeyasu, Masanori;
JNC-TN8440 2001-011, 146 Pages, 2001/06
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.
Kato, Tomoko; ; *; ; Ishiguo, K.; Ikeda, Takao*; RICHARD LITTLE*
JNC-TN8400 2001-003, 128 Pages, 2001/03
In the safety assessment of a high-level radioactive waste (HLW) disposal system, it is required to estimate radiological impacts on future human beings arising from potential radionuclide releases from a deep repository into the surface environment. In order to estimate the impacts, a biosphere model is developed by reasonably assuming radionuclide migration processes in the surface environment and relevant human lifestyles. Releases from the repository might not occur for many thousands of years after disposal. Over such timescales, it is anticipated that the considerable climatic change, for example, induced by the next glaciation period expected to occur in around ten thousand years from now, will have a significant influence on the near surface environment and associated human lifestyles. In case of taking these evolution effects into account in modeling, it is reasonable to develop several alternative models on biosphere evolution systems consistent with possible future conditions affected by expected climatic changes. In this study, alternative biosphere models were developed taking effects of possible climatie change into account. In the modeling, different climatic states existing in the world from the present climate condition in Japan are utilized as an analogy. Estimation of net effects of the climatic change on biosphere system was made by comparing these alternative biosphere models with a constant biosphere model consistent with the present climatic state through flux to dose conversion factors derived from each one.
Shinohara, Kunihiko; ; ; ; ; Kano, Yutaka;
JNC-TN8440 2001-004, 62 Pages, 2001/02
Concerming about the action for the criticality accident in JCO Co., Ltd. (JCO) occurred at 10:35 on 30 Sept. 1999, Japan Nuclear Cycle Development Institute(JNC) established "JNC's task force" at 12:35 on the same date in conjuction with Head Office and Tokai Works. And JNC's task force had supported the government of Japan, the local governments and JCO humanly, physically and technically until the jobs of the task force was transferred to "Support Assembly for Countermeasure and Research of JCO Criticality Accident" and routine line on 12 Oct. 1999. This report compiled the results of the environmental monitoring performed by JNC based on the request from the government of Japan and the local governments.
Maruo, Yoshihiro; ; ;
JNC-TN8440 2001-001, 135 Pages, 2000/12
; *; Sukegawa, Yasuhiro*; Miyo, Hiroaki
JNC-TN8440 2000-021, 180 Pages, 2000/10
At outside waste storage pits, containers for storage of wastes corroded and were flooded, and it was confirmed on August 26, 1997. Confirmation of contamination of the pits outskirts, installation of sheets to prevent rainwater from flowing into the pits, drawing stay water were executed, promptly. Design and authorization works of the work house and waste treatment devices to take out wastes of the pits were executed too. After construction of the work house, taking out wastes of the pits started, and finished on April 10, 1998. Investigations of the inflow point of rainwater and leak of stay water were executed next. The results were reported to Science and Thechnology Agency (STA), adjoining authorities on December 21, 1998. After decontamination of the pits inner walls to background level of the radioactivity which included general concrete, control area was removed, and the pits were closed by concrete. Measures of closing of the pits were prepared from the middle of August, 1999, and dismantlement of unnecessaly instruments started. Decontamination of the pits started fiom the beginning of September, 1999. The above works finished on June 30, 2000. After decontamination of the pits, STA, adjoining authorities confirmed the circumstances. Work pouring concrete into the pits was executed three times (three levels), and finished on August 31, 2000. In addition to above, the amount of concrete poured into the pits was about 1,200 m. This report compiled the photographs of the works from confirmation of stay water at August, 1997 by finish of measures of closing of the pits at September, 2000.
JNC-TN8400 2000-028, 70 Pages, 2000/10
This report describes the study done by the author as a postdoctoral research associate at Japan Nuclear Cycle Development Institute. This report is divided into two parts: improvements in accuracy in determination of thermal neutron capture cross sections, and improvements in accuracy of photo-nuclear absorption cross section measurements using the HHS. (1)In the measurements of thermal neutron capture cross sections using an activation method, accuracies of the final results attained are limited by (1) accuracy of -ray peak detection efficiencies, and (2) accuracies of -ray emission probabilities. In this study; to determine thermal neutron capture cross sections more accurately, the following researches have been done using a newly developed three-dimensional coincidence measurement system: (1)accurate determination of -ray standard sources using a - coincidence method, for precise calibration of -ray peak detection efficiency, and (2) development of a - coincidence measurement system using a plastic scintillation detector as a -ray detector, for the determination of -ray emission probabilities of short-lived nuclides, and measurement of -ray emission probabilities of Tc nuclide using the coincidence system. (2)To transform radioactive nuclides with small thermal neutron capture cross sections, use of photonuclear absorption reaction has been suggested. In order to transform these nuclides efficiently using the reaction, one has to know detailed behavior of the photo-absorption cross sections. In this study, a Monte-Carlo simulation code has been used to create a standard set of -ray response functions of the high-resolution high-energy spectrometer (HHS), to enable reliable analyses of the data obtained by the spectrometer.
Hatakeyama, Mutsuo; Ito, Hirokuni; Yanagihara, Satoshi
JAERI-Tech 2000-056, 38 Pages, 2000/09
no abstracts in English
; Shinohara, Kunihiko; ; ; ; Isozaki, Tokuju; ; *
JNC-TN8440 2000-003, 93 Pages, 2000/08
The investigation on the radioactivity concentration for gross beta, H and Cs in seawater collected around the discharge point had been performed in order to grasp the change of the activity level of the coastal seawater offshore the JNC Tokai Works from the low level liquid effluent of the reprocessing plant. After the investigation on the radioactivity in seawater during the hot examination, the detailed investigation on the environmental effects from the liquid effluent of JNC reprocessing plant has been performed since July 1978 on the basis of the request from Ibaraki prefecture as the full-scale operation of the reprocessing plant. Consequently, no increase of the radioactive concentration due to the discharged effluent has been observed. And also, as the result of the consideration to the investigation on the environmental effect from the liquid effluent throughout 22 years since 1978, no change of the radioactive concentration level in seawater was recognized.
Miyabe, Kenjiro; Takasaki, Koji; *; *
JNC-TN8420 2000-007, 100 Pages, 2000/08
The commercial detergents, which are cleansing cream, shampoo, neutral detergent, etc., were examined in order to select the body cleaners that are substitutes for the titanium dioxide paste. JNC entrusted Japan Environment Research Corporation Limited with these examinations since 1997. In 1997 and 1998, the commercial detergents were examined for Ce-144, Cs-137 and Ru-106. In 1999, 22 detergents were examined for Co-60 from the result of the past examinations. In this examination, the radioactive solution of Co-60 was dropped on the pig-skin samples. These samples were washed with each detergent after 5 minutes and 40 minutes. The decontamination factors of detergents were estimated by the radioactive ratio of the samples before and after washing. As a result of this examination, the decontamination factors for Co-60 was the same as the decontamination factors for Ce-144 and Cs-137, and 11 detergents were nominated as the cleaner that have the decontamination factor more than that of titanium dioxide paste.
; Shinohara, Kunihiko; ; ; ; Takeyasu, Masanori;
JNC-TN8440 2000-007, 141 Pages, 2000/06
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 1999 to March 2000. Appendices present comprehensive information, such as monitoring program, monitoring results, meteorological data and annual discharges from the plant.
JNC-TJ8420 2000-013, 96 Pages, 2000/03
no abstracts in English
*; Sato, Seiji*; *; Naruki, Kaoru
JNC-TJ1400 2000-010, 71 Pages, 2000/03