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CMiyazawa, Takeshi; Kikuchi, Yuta*; Ando, Masami*; Yu, J.-H.*; Yabuuchi, Kiyohiro*; Nozawa, Takashi*; Tanigawa, Hiroyasu*; Nogami, Shuhei*; Hasegawa, Akira*
Journal of Nuclear Materials, 575, p.154239_1 - 154239_11, 2023/03
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)Iketani, Shotaro; Yokobori, Tomohiko; Ishikawa, Joji; Yasuhara, Toshiyuki*; Kozawa, Toshiyuki*; Takaizumi, Hirohide*; Momma, Takeshi*; Kurosawa, Shingo*; Iseda, Hirokatsu; Kishimoto, Katsumi; et al.
JAEA-Review 2018-016, 46 Pages, 2018/12
JAEA-Review-2018-016.pdf:12.79MB
Japan Atomic Energy Agency (JAEA) adopts melting process for the waste processing and packaging method of radioactive miscellaneous solid waste in NSRI because melting process is effective in radioactivity evaluation, volume reduction, and stabilization treatment. Metal melting processing facilities, Incinerator, and Nonmetal melting processing facilities (hereinafter referred to as melting process facilities) have taken lots of safety measures, including measures for preventing the recurrence of the fire accidents. To exchange opinions and discuss the validity of these measures and so on with internal personnel and external experts, "Discussions on Melting Process Facilities" was held. As a document collection, this paper summarizes presentation materials of discussion meetings. Presentation materials describe "Outline of AVRF", "Safety measures in the melting facilities in WVRF", "Operation management of the melting facilities in WVRF", "Comparison of the past accident cases between facilities in and outside Japan and WVRF", and "Introduction of past accident cases and safety measures in other facilities from each committee".
Saito, Hiroshi; Nozawa, Takashi; Takemiya, Hiroshi; Seki, Akiyuki; Matsubara, Takeshi; Saito, Kimiaki; Kitamura, Akihiro
JAEA-Review 2017-040, 34 Pages, 2018/03
JAEA-Review-2017-040.pdf:9.52MB
The accidents at Fukushima Daiichi Nuclear Power Station on March 11th 2011, released significant amount of radionuclide to the environment. It has migrated to the human habitation and raised concerns of possible effect on human health, and for that a lot of researches have been performed. JAEA created and opened "Database for Radioactive Substance Monitoring Data" for usage of obtained data. For accurate modelling and future forecast using numerical code and the data, "Supporting Environment for Processing Simulation Codes" has been operated. In addition, research results have been opened as Q&A style "Knowledge Base for Environmental Remediation" in JAEA's website. The "Comprehensive Evaluation System" composed of these components, should act more interrelated and integrated as one system. Besides, information dissemination is not enough to the outside. The report summarizes the current status, remaining issues and expected improvement of each component and the system.
Takamizawa, Hisashi; Shimizu, Yasuo*; Inoue, Koji*; Nozawa, Yasuko*; Toyama, Takeshi*; Yano, Fumiko*; Inoue, Masao*; Nishida, Akio*; Nagai, Yasuyoshi*
Applied Physics Express, 9(10), p.106601_1 - 106601_4, 2016/10
Times Cited Count：0 Percentile：0(Physics, Applied)Nakashio, Nobuyuki; Osugi, Takeshi; Iseda, Hirokatsu; Tohei, Toshio; Sudo, Tomoyuki; Ishikawa, Joji; Mitsuda, Motoyuki; Yokobori, Tomohiko; Kozawa, Kazushige; Momma, Toshiyuki; et al.
Journal of Nuclear Science and Technology, 53(1), p.139 - 145, 2016/01
Times Cited Count：1 Percentile：10.6(Nuclear Science & Technology)no abstracts in English
Takeuchi, Tomoaki; Kakubo, Yuta*; Matsukawa, Yoshitaka*; Nozawa, Yasuko*; Toyama, Takeshi*; Nagai, Yasuyoshi*; Nishiyama, Yutaka; Katsuyama, Jinya; Yamaguchi, Yoshihito; Onizawa, Kunio; et al.
Journal of Nuclear Materials, 452(1-3), p.235 - 240, 2014/09
Times Cited Count：40 Percentile：95.02(Materials Science, Multidisciplinary)Microstructures and hardness of stainless steel weld overlay cladding of reactor pressure vessels subjected to the thermal aging at 400 C for 100-10,000 h were investigated using atom probe tomography and nanoindentation technique. The Cr concentration fluctuation in the 
-ferrite phase caused by spinodal decomposition rapidly progressed by the 100 h aging while NiSiMn clusters increased in number density at 2,000 h and coarsened at 10,000 h. The hardness of the -ferrite phase also rapidly increased at the short aging time. The Cr concentration fluctuation and the hardness were in good correlation with the degree of the Cr concentration fluctuation rather than the formation of the NiSiMn clusters. These results strongly suggested that the dominant factor of the hardening of the -ferrite phase by the thermal aging was Cr spinodal decomposition.
Takeuchi, Tomoaki; Kakubo, Yuta*; Matsukawa, Yoshitaka*; Nozawa, Yasuko*; Toyama, Takeshi*; Nagai, Yasuyoshi*; Nishiyama, Yutaka; Katsuyama, Jinya; Yamaguchi, Yoshihito; Onizawa, Kunio
Journal of Nuclear Materials, 449(1-3), p.273 - 276, 2014/06
Times Cited Count：20 Percentile：81.41(Materials Science, Multidisciplinary)Microstructural changes and hardness of stainless steel weld overlay cladding of reactor pressure vessels subjected to the neutron irradiation with a dose of 7.2 
10
n cm
(E 
1 MeV) and a flux of 1.1 10
n cm s
at 290C were investigated by atom probe tomography and with nanoindentation technique. In order to isolate the effect of the irradiation, we compared the results of the measurements of the irradiated sample with that of the aged one at 300C for the time equivalent to the irradiation. The Cr concentration fluctuation was enhanced in the -ferrite phase of the irradiated sample. In addition, the enhancement of the concentration fluctuation of Si, which was not observed in the aged sample, was observed. The hardening at the -ferrite phase was occurred by both the irradiation and the aging. However, the former was more than that expected from the Cr concentration fluctuation, which suggested that the Si concentration fluctuation and irradiation-induced defects were possible origins of the additional hardening.
Hase, Yoshihiro; Nozawa, Shigeki; Okada, Tomoyuki*; Asami, Itsuo*; Nagatani, Takeshi*; Matsuo, Yoichi*; Kanazawa, Akira*; Honda, Kazushige*; Narumi, Issei
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 95, 2013/01
Uesaka, Takahiro; Kozawa, Masachiyo; Matsumoto, Junko; Endo, Masayuki; Kinoshita, Junichi; Suzuki, Takeshi; Suzuki, Hisao; Morishita, Satoru; Sakamoto, Yu
JAEA-Technology 2012-015, 29 Pages, 2012/06
JAEA-Technology-2012-015.pdf:3.22MB
In Japan Atomic Energy Agency Nuclear Science Research Institute waste treatment building No.2 treat intermediate-level solid waste. Solid wastes are reduced in volume by compaction. They are then canned in stainless can, which are subsequently put in 200-liter concrete-lined drums or 1-m
concrete containers, filled with concrete. To prepare for disposal in future, be able to make fit with the technical standard of waste package, we were asked to change the lid type shielded container. Therefore due to the change of lid type shielded container, we confirmed integrity of it with evaluation of close volt by drop analysis, evaluation of shielding, and drop test with a prototype model.
Hase, Yoshihiro; Nozawa, Shigeki; Okada, Tomoyuki*; Asami, Itsuo*; Nagatani, Takeshi*; Matsuo, Yoichi*; Kanazawa, Akira*; Honda, Kazushige*; Narumi, Issei
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 100, 2012/01
Sudo, Tomoyuki; Nakashio, Nobuyuki; Osugi, Takeshi; Mimura, Ryuji; Ishihara, Keisuke; Satomi, Shinichi; Myodo, Masato; Momma, Toshiyuki; Kozawa, Kazushige
JAEA-Technology 2010-041, 38 Pages, 2011/01
JAEA-Technology-2010-041.pdf:4.73MB
The super compactor in the AVRF treats compactible metal wastes mainly generated from research reactors in the Nuclear Science Research Institute of JAEA. Those wastes are compacted with the maximum about 2,000-ton force. The supercompacted wastes are packed into the container and then immobilized with cementitious materials. The solidified wastes (containing supercompacted wastes) become an object for near surface disposal with artificial barrier. For disposal, the solidified wastes must be satisfied the technical criteria. One of the important indicators is the void ratio in the solidified wastes. In this report, we manufactured the supercompacted wastes with the ordinary treatment method for actual wastes treated in the AVRF and immobilized with a mortar grout. The void ratio of the solidified wastes were evaluated in consideration for concrete vault disposal. As a result, We confirmed the integrity of the solidified wastes from a point of view of void ratio.
Tohei, Toshio; Nakashio, Nobuyuki; Osugi, Takeshi; Ishikawa, Joji; Mizoguchi, Takafumi; Hanawa, Ritsu; Someya, Keita*; Takahashi, Kenji*; Iseda, Hirokatsu; Kozawa, Kazushige; et al.
JAEA-Technology 2010-008, 28 Pages, 2010/06
JAEA-Technology-2010-008.pdf:5.0MB
The Waste Volume Reduction Facility (WVRF) was constructed for volume reduction and the chemical stabilization of the low level radioactive waste in the Nuclear Science Research Institute of JAEA. The metal melting system in the WVRF treats radioactive metal waste. From the experience of trial operations, the improvement has conducted on the casting process in the metal melting system. The performance of the improved casting process was verified through the trial operations from Oct. 2008. In this report, we describe the reduction of the processing time, of the utilities consumption, of the load of maintenance on the improved casting process.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Ozawa, Masaki; Suzuki, Shinichi; Takeshita, Kenji*
Solvent Extraction Research and Development, Japan, 17, p.19 - 34, 2010/00
A hydrometallurgical separation technologies by novel solvent extraction (SX), ion exchange chromatography (IXC) and electrolytic extraction techniques are reviewed as separation tools for light PGM (Ru, Rh, Pd), Tc and 
-elements in high level liquid wastes of the nuclear fuel cycle. The SX process using N,N-dialkylamide can isolate U(VI) from fission products without Pu(IV) valence control, and extractants with soft-hard hybrid donors (PTA and PDA) and those containing six soft donors (TPEN) show good separation of actinides (III) from lanthanides (III). The catalytic electrolytic extraction (CEE) process utilizing Pd
or Rh can effectively separate platinum group metals (PGM), Tc and Re by means of controlled under potential deposition (UPD). Some of the basic work on the hydrometallurgical separation of the elements of interest has been carried out through the strategic Advanced (Adv.-) ORIENT Cycle research in Japan.
Shirao, Tsukasa*; Nagatani, Takeshi*; Nozawa, Shigeki; Hase, Yoshihiro; Tanaka, Atsushi; Narumi, Issei
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 79, 2009/12
no abstracts in English
Higuchi, Hidekazu; Osugi, Takeshi; Nakashio, Nobuyuki; Momma, Toshiyuki; Tohei, Toshio; Ishikawa, Joji; Iseda, Hirokatsu; Mitsuda, Motoyuki; Ishihara, Keisuke; Sudo, Tomoyuki; et al.
JAEA-Technology 2007-038, 189 Pages, 2007/07
JAEA-Technology-2007-038-01.pdf:15.13MBJAEA-Technology-2007-038-02.pdf:38.95MBJAEA-Technology-2007-038-03.pdf:48.42MBJAEA-Technology-2007-038-04.pdf:20.53MBJAEA-Technology-2007-038-05.pdf:10.44MB
The Advanced Volume Reduction Facilities (AVRF) is constructed to manufacture the waste packages of radioactive waste for disposal in the Nuclear Science Research Institute of the Japan Atomic Energy Agency. The AVRF is constituted from two facilities. The one is the Waste Size Reduction and Storage Facility (WSRSF) which is for reducing waste size, sorting into each material and storing the waste package. The other is the Waste Volume Reduction Facility (WVRF) which is for manufacturing the waste package by volume reducing treatment and stabilizing treatment. WVRF has an induction melting furnace, a plasma melting furnace, an incinerator, and a super compactor for treatment. In this report, we summarized about the basic concept of constructing AVRF, the constitution of facilities, the specifications of machineries and the state of trial operation until March of 2006.
AlOzawa, Akira*; Matsuta, Kensaku*; Nagatomo, Takashi*; Mihara, Mototsugu*; Yamada, Kazunari*; Yamaguchi, Takayuki*; Otsubo, Takashi*; Momota, Sadao*; Izumikawa, Takuji*; Sumikama, Toshiyuki*; et al.
Physical Review C, 74(2), p.021301_1 - 021301_4, 2006/08
Times Cited Count：43 Percentile：89.18(Physics, Nuclear)no abstracts in English
Higashinaka, Motonori*; Sano, Yukiko*; Kozawa, Takeshi*
JNC TJ5410 2005-009, 96 Pages, 2005/08
JNC-TJ5410-2005-009.pdf:36.66MB
This document is to report the result of existing seismic data reprocessing around Horonobe town, Hokkaido, Japan, which is a part of the Horonbe Undergounrd Research Project. The main purpose of the re-processing is to recognize the subsurface structure of Omagari Fault and fold sysytem around Omagari Fault. The seismic lines fore re-processing are TYHR-A3 and SHRB-2line, which is surceyed in 1975. Applying weathering static correction using refraction analysis and noise suprression procedure, we have much enhanced sesmic prifile.
Kondo, Ryoichi*; Ozawa, Takeshi*; Horie, Junnosuke*; Handa, Hiroyuki*
PNC TJ202 82-03, 76 Pages, 1982/02
A supplemental study on the JOYO's shielding analysis was performed focussing attention on the behavior of neutron and 
-ray fluxes around the detector guide tube of channel a and on the evaluation of the primary sodium activation with use made of the two-dimensional discrete ordinates transport code. It has been found out that secondary rays emitted from a thin guide tube material of SS-304 has a strong effect of enhancing gamma doserates in the guide tube penetrating through a graphite shielding. The effect of the guide tube penetrating a heavy concrete pedestal has been revealed to be a streaming of neutrons and gammas. It can be concluded that the effect of the detector guide tube on the neutron and ray should be taken into account when comparing the calculated values with experimental values. The neutron flux distribution in the full reactor lower axial two dimensional geometry has been calculated and used, together with the results obtained by the upper axial two dimensional a
Ozawa, Masaki; Yokoo, Takeshi*
Nihon Genshiryoku Gakkai Dai-18-Kai "Bunri Kaku Henkan Kogaku" Kenkyu Semmon Iinkai, Nihon Genshiryoku Gakkai-Shi, ,
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