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F from 
O
?Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.
Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05
Times Cited Count：18 Percentile：73.44(Physics, Multidisciplinary)The structure of a neutron-rich F nucleus is investigated by a quasifree (
) knockout reaction. The sum of spectroscopic factors of 
orbital is found to be 1.0 
0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 
35% O
, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the 
proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.
Nakano, Masanao; Fujii, Tomoko; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yamada, Ryohei; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; et al.
JAEA-Review 2019-045, 120 Pages, 2020/03
JAEA-Review-2019-045.pdf:2.54MB
Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2018. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yamada, Ryohei; Yoshii, Hideki*; Hiyama, Yoshinori*; Otani, Kazunori*; et al.
JAEA-Review 2018-028, 120 Pages, 2019/02
JAEA-Review-2018-028.pdf:2.69MB
Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2017. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Nakano, Masanao; Fujita, Hiroki; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yoshii, Hideki*; Hiyama, Yoshinori*; Otani, Kazunori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.
JAEA-Review 2017-037, 119 Pages, 2018/03
JAEA-Review-2017-037.pdf:2.58MB
Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2016. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Nagaoka, Mika; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.
JAEA-Review 2017-001, 115 Pages, 2017/03
JAEA-Review-2017-001.pdf:3.57MB
Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2015. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.
JAEA-Review 2015-030, 115 Pages, 2015/12
JAEA-Review-2015-030.pdf:25.28MB
Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2014. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.
Ishiyama, Toru; Kawasaki, Ichio; Asano, Naoki
Boira Kenkyu, (366), p.9 - 15, 2011/04
The Hydrazine has been used for water treatment of the boiler in general industry scene. It has been used in NCL from 1995, too. Ministry of Health, Labour and Welfare do announcement about using hydrazine in 2006, and NCL began to try operation without hydrazine. Hydrazine was replaced to the other reagent that was selected based on the result of a research and an evaluation. Therefore safeguard of environment and labour was carried on by new operation method of water treatment from 2010. This report was described about the result of research and development.
Taniguchi, Naoki; Suzuki, Hiroyuki; Kawasaki, Manabu; Naito, Morimasa; Kobayashi, Masato*; Takahashi, Rieko*; Asano, Hidekazu*
Corrosion Engineering, Science and Technology, 46(2), p.117 - 123, 2011/04
Times Cited Count：10 Percentile：48.77(Materials Science, Multidisciplinary)Carbon steel has been selected as one of the candidate materials for overpack for geological disposal of high-level radioactive waste in Japan. Corrosion of carbon steel is divided into two types; general corrosion and localized corrosion. In this study, propagation behaviors of general and localized corrosions (pitting corrosion and crevice corrosion) were investigated by immersion tests of carbon steel under aerobic condition. The results of the immersion tests showed that the growth rate of corrosion was strongly dependent on the environmental condition and steel type, but the upper limit of pitting factor (the ratio of the maximum corrosion depth and the average corrosion depth) was approximately determined by only average corrosion depth. Based on these experimental data and literature data, an empirical model that predicts the maximum corrosion depth of an overpack from average corrosion depth was developed by applying the extreme value statistical analysis using the Gumbel distribution function.
Kobayashi, Masato*; Yokoyama, Yutaka*; Takahashi, Rieko*; Asano, Hidekazu*; Taniguchi, Naoki; Naito, Morimasa
Corrosion Engineering, Science and Technology, 46(2), p.212 - 216, 2011/04
Times Cited Count：4 Percentile：28.30(Materials Science, Multidisciplinary)The corrosion behaviour of a carbon steel weld joint under anaerobic conditions was investigated to estimate the long-term integrity of the carbon steel overpack. The weld specimens in this study were produced using three welding methods: GTAW, GMAW and EBW. General corrosion was observed for each immersion specimen and the weld joint corrosion rate was the same as or less than that of the base metal. The hydrogen concentration absorbed during immersion testing was less than 2.48
10
mol kg[Fe]
(0.05 ppm) after three years, a value regarded as having little influence on hydrogen embrittlement. The susceptibility to hydrogen embrittlement was highest in the base metal, suggesting that there was little adverse effect on the weld joint from welding. The welded carbon steel overpack is assumed to maintain its resistance to corrosion as a disposal container for the expected lifetime under anaerobic underground conditions.
Ishiyama, Toru; Kawasaki, Ichio; Asano, Naoki
Boira, Nyusu, (735), P. 6, 2010/09
The Hydrazine has been used for water treatment of the boiler in general industry scene. It has been used in NCL from 1995, too. Ministry of Health, Labour and Welfare do announcement about using hydrazine in 2006, and NCL began to try operation without hydrazine. Hydrazine was replaced to the other reagent that was selected based on the result of a research and an evaluation. Therefore safeguard of environment and labour was carried on by new operation method of water treatment from 2010. This report was described about the result of research and development.
Ishiyama, Toru; Asano, Naoki; Kawasaki, Ichio
JAEA-Technology 2009-066, 79 Pages, 2010/02
JAEA-Technology-2009-066.pdf:15.64MB
Tokai Utility Center (TUC) is the facility that products and feeds steam for Tokai Reprocessing Plant (TRP), Plutonium Fuel Production Facility (PFPF), etc. The boiler system needs the management based on the law of "Industrial safety and Health Act" and "Act on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors". In this situation, activity of preservation of environment and energy-save are carried out by means of the improvement of steam generation process and the change of additive to water. Quality assurance procedure has been applied in order to improve the boiler operation continuously. This report describes about various activities of the management, the environment, the energy-saving, and a future action.
Yokoyama, Yutaka*; Mitsui, Hiroyuki*; Takahashi, Rieko; Taniguchi, Naoki; Asano, Hidekazu*; Naito, Morimasa; Yui, Mikazu
JAEA-Research 2008-072, 232 Pages, 2008/10
JAEA-Research-2008-072.pdf:45.2MB
It is possible that the corrosion resistance at the overpack welds is different from that at base metal due to the differences of material properties. In this study, corrosion behavior of welded joint for carbon steel was compared with base metal using the specimens taken from welded joint model fabricated by TIG (Tungsten Arc Welding, GTAW), MAG (Gas Metal Arc Welding, GMAW) and EBW (Electron Beam Welding) respectively. The results of these corrosion tests indicated that the corrosion resistance to general corrosion, pitting corrosion and crevice corrosion at welded metal of TIG and MAG was inferior to base metal. No deterioration of corrosion resistance was observed in any corrosion modes for EBW, which does not need filler material. Neither the base metals nor the welds is not susceptible to SCC under the carbonate concentration near that of the disposal environment.
Mitsui, Hiroyuki*; Takahashi, Rieko*; Taniguchi, Naoki; Otsuki, Akiyoshi*; Asano, Hidekazu*; Yui, Mikazu
JAEA-Research 2006-080, 322 Pages, 2006/12
JAEA-Research-2006-080.pdf:90.52MB
There is some possibility that the corrosion resistance of overpack welds is different from that of base metal due to the differences of material properties. In this study, corrosion behavior of welded joint for carbon steel was compared with base metal using the specimens taken from welded joint model fabricated by TIG, MAG and EBW respectively. The corrosion tests were performed for following four items. (1) Passivation behavior and corrosion type, (2) Propagation of general corrosion, pitting corrosion and crevice corrosion under aerobic condition, (3) Stress corrosion cracking susceptibility, (4) Propagation of general corrosion and hydrogen embrittlement under anaerobic condition. The results of these corrosion tests indicated that the corrosion resistance of welded metal by TIG and MAG was inferior to base metal for general corrosion, pitting corrosion and crevice corrosion. It was implied that the filler materials used for welding affected the corrosion resistance. No deterioration of corrosion resistance was observed in any corrosion modes for EBW, which does not need filler material. The susceptibility to stress corrosion cracking of welded metal and heat affected zone was lower than that of base metal.
Mitsui, Hiroyuki*; Taniguchi, Naoki; Otsuki, Akiyoshi*; Kawakami, Susumu; Asano, Hidekazu*; Yui, Mikazu
JAEA-Research 2006-031, 88 Pages, 2006/06
JAEA-Research-2006-031.pdf:4.72MB
The corrosion experiments for welded carbon steel were planed to contribute to an assessment of long-term integrity of carbon steel overpack welds considering corrosion damage specific to overpack welds. Based on this plan, electrochemical tests for welded carbon steel using the samples welded by EBW and TIG were carried out, and the corrosion behavior of welded zone was compared with that of base metal. The results of anodic polarization tests in 0.01M and 0.1M carbonate aqueous solutions for base metal, heat affected zone and welded metal indicated that; -As for EBW, the anodic polarization curves were not affected by welding although the metallurgical structures vary with base metal, heat affected zone and welded metal. -As for TIG, the current density of welded metal was larger than that of base metal and of heat affected zone, and local dissolution with immediate increase in current density was observed in 0.01M-pH10 carbonate aqueous solution.
Shinohara, Nobuo; Asano, Yoshie; Hirota, Naoki*; Hokida, Takanori; Inoue, Yoji; Kumata, Masahiro; Nakahara, Yoshinori*; Oda, Tetsuzo*; Uchikoshi, Takako*; Yamamoto, Yoichi
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 3 Pages, 2005/10
Research activities of JAERI related to the CTBT verification regime are presented in the International Conference. The subjects of this presentation are (1) an overview of the CTBT verification regime, (2) construction and operation of the radionuclide monitoring stations of Okinawa (RN37) and Takasaki (RN38) and the certified radionuclide laboratory (RL11), and (3) preparation of the National Data Center at Tokai (JAERI NDC) for radionuclide data. The RN38 station has been certified by the CTBTO/PrepCom and sending the measured data every day. The infrastructures and operational manuals for RN37 and RL11 are now preparing for their operations. The JAERI NDC has experimentally analyzed and evaluated the radionuclide data from all over the world through International Data Center (IDC). As an example of the JAERI NDC works, atmospheric dispersion backtracking system has been developing by using WSPEEDI (Worldwide Version of System for Prediction of Environmental Emergency Dose Information) code to estimate a source location of radionuclide release by nuclear explosion/accident.
Asano, Hidekazu*; Taniguchi, Naoki; Kawakami, Susumu; Yui, Mikazu
JNC TY8400 2004-008, 30 Pages, 2004/04
It is necessary to understand the corrosion behavior of welds in overpack for ensuring the quality of welding, and improving the long term reliability of overpack. In this study, the method for evaluation of corrosion of welded joint was planned by Radioactive Waste Management Funding and Research Center (RWMC) and Japan Nuclear Cycle Development Institute (JNC). RWMC has been developed the overpack welding techniques and the inspection techniques of welded joint. In this study, RWMC provided the information on current status of welding techniques for applying the overpacks. Electron Beam Welding (EBW) and Tungsten Inert Gas Welding (TIG) were prospected to be available for overpack and the results of the examinations to find adequate conditions for overpack welding were presented. JNC has been studying the corrosion behavior and lifetime of overpack, and provided the information on corrosion of welded carbon steel under repository conditions. According to immersion tests by JNC, it was shown that corrosion rates of carbon steel welded by EBW were almost equal to those of base metal under anaerobic condition, which is representative condition in repository environment. Based on the information provided by RWMC and JNC, the research subjects on the corrosion of welds were extracted and the concept of corrosion tests for overpack welds was given.
Kobayashi, Masato*; Takahashi, Rieko*; Asano, Hidekazu*; Taniguchi, Naoki; Fujita, Tomoo
no journal, ,
Susceptibility of hydrogen embrittlement of carbon steel weld joint was evaluated by slow strain rate testing (SSRT) in consideration of a diffusive hydrogen concentration and a presence of a fine flaw which is hard to detect by ultrasonic testing due to the dimension. In order to avoid an effect of metallurgical micro structure, normalized specimens were prepared to the SSRT. The results of SSRT showed the rupture elongation decreases with an increase in hydrogen concentration. And observation of the fracture surface and measurement of the hydrogen concentration in the specimens showed a generation of a crack initiated from fine flaw at up to a certain value of hydrogen concentration. Although decreasing of fracture strain was observed on the specimens fracture morphology, it was evaluated as no significant effect in comparison with the effect of the concentration of the diffusive hydrogen in the specimens. These results suggest that a presence of a fine flaw has a small impact on the hydrogen embrittlement of weld joint.
Kobayashi, Masato*; Takahashi, Rieko*; Asano, Hidekazu*; Taniguchi, Naoki; Naito, Morimasa
no journal, ,
Overpack is one of the components of EBS (Engineering barrier system) and is required to contain the radioactive waste at least for 1000 years. It has been evaluated that carbon steel overpack can be achieved lifetime of over 1000 years in expected deep underground environment by securing 40mm corrosion allowance. However, since the welded zone have different characteristics from the base metal in chemical composition and microstructure, its corrosion behavior would possible to be different from that in base metal. Concerning such background, corrosion tests to evaluate the corrosion resistance of welded zone (including heat affected zone and welded metal) were carried out and the effects of welding on the corrosion properties were investigated.
Mitsui, Hiroyuki*; Takahashi, Rieko*; Otsuki, Akiyoshi*; Asano, Hidekazu*; Taniguchi, Naoki; Yui, Mikazu
no journal, ,
The slow strain rate tests(SSRT) of carbon steel were performed in sodium carbonate-sodium-bicarbonate aqueous solution to acquire knowlwdges regarding susceptibility to stress corrosion cracking of welded joint of carbon steel overpack for high-level radioiactive waste disposal. The specimens were taken from thick cylindrical sample welded by TIG and EBW, and then SSRT tests were applied to the each of specimens of base metal, heat affected zone and welded metal. Based on the results, the susceptibility to stress corrosion cracking of welded joint of carbon steel overpack was evaluated.
Morishita, Yuki; Sagawa, Naoki; Fujisawa, Makoto; Kurosawa, Shunsuke*; Sasano, Makoto*; Hayashi, Masateru*; Tanaka, Hiroki*
no journal, ,
This study reports the effects of different types of radiation on a high-resolution alpha imager, developed using an Electron Multiplying Charge-Coupled Device (EMCCD) camera. The imager was originally designed to visualize Pu oxide particles in decommissioning sites, where other types of radiation such as beta particles, gamma-rays, and neutrons are also present. The study aims to confirm the effects of these radiations on the imager and to develop a discrimination method between alpha particles and other radiations. The measurement of alpha particles, beta particles, gamma-rays, and neutrons were performed. The discrimination method was based on the characteristics of the image distribution, where the image values were binarized and a Gaussian filter was applied to count the number of alpha particle spots. The results show that it is possible to discriminate between alpha and gamma (neutron) rays using the difference in intensity. The study provides important information for the development of radiation detection techniques in decommissioning sites.
