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Suzuki, Kazuhiro; Motooka, Takafumi; Tsukada, Takashi; Terakawa, Yuto; Ichise, Kenichi; Numata, Masami; Kikuchi, Hiroyuki
JAEA-Technology 2014-004, 29 Pages, 2014/03
JAEA-Technology-2014-004.pdf:3.66MB
By the effect of the Great East Japan Earthquake, seawater was injected into spent fuel pools in unit 2, 3 and 4 at Fukushima Daiichi Nuclear Plant in order to cool spent fuels. It is known that chloride ion contained in seawater could cause pitting corrosion for metallic materials. It was concerned that radioactive products inside of fuel cladding tubes might be escaped through the pits. Therefore we have investigated the pit initiation condition of fuel cladding tubes by measuring pitting potential in order to evaluate stability of the enclosure function of fuel cladding tubes in spent fuel pools containing sea salt. In this report, we describe the development of specimen preparation techniques for pitting measurement of spent fuel cladding tubes having high radioactivity. By accomplishing of the development of the specimen preparation techniques, we could evaluate pit initiation condition of spent fuel cladding tubes in water containing sea salt.
Matsui, Yoshinori; Takahashi, Hiroyuki; Yamamoto, Masaya; Nakata, Masahito; Yoshitake, Tsunemitsu; Abe, Kazuyuki; Yoshikawa, Katsunori; Iwamatsu, Shigemi; Ishikawa, Kazuyoshi; Kikuchi, Taiji; et al.
JAEA-Technology 2009-072, 144 Pages, 2010/03
JAEA-Technology-2009-072.pdf:45.01MB
"R&D Project on Irradiation Damage Management Technology for Structural Materials of Long-life Nuclear Plant" was carried out from FY2006 in a fund of a trust enterprise of the Ministry of Education, Culture, Sports, Science and Technology. The coupled irradiations or single irradiation by JOYO fast reactor and JRR-3 thermal reactor were performed for about two years. The irradiation specimens are very important materials to establish of "Evaluation of Irradiation Damage Indicator" in this research. For the acquisition of the examination specimens irradiated by the JOYO and JRR-3, we summarized about the overall plan, the work process and the results for the study to utilize these reactors and some facilities of hot laboratory (WASTEF, JMTR-HL, MMF and FMF) of the Oarai Research-and-Development Center and the Nuclear Science Research Institute in the Japan Atomic Energy Agency.
Sakuraba, Naotoshi; Numata, Masami; Komiya, Tomokazu; Ichise, Kenichi; Nishi, Masahiro; Tomita, Takeshi; Usami, Koji; Endo, Shinya; Miyata, Seiichi; Kurosawa, Tatsuya; et al.
JAEA-Technology 2009-071, 34 Pages, 2010/03
JAEA-Technology-2009-071.pdf:21.07MB
As a part of maintenance technology of a large-sized glove box for handling of TRU nuclides, we developed replacement technology for front acrylic panels using the bag-in/bag-out method and applied this technology to replace the deteriorated front acrylic panels at Waste Safety Testing Facility (WASTEF) in Nuclear Science Research Institute of Japan Atomic Energy Agency (JAEA). As a consequence, we could safely replace the front acrylic panels under the condition of continuous negative pressure only with partial decontamination of the glove box. We also demonstrated that the present technology is highly effective in points of safety, workability and cost as compared to the usual replacement technology for front acrylic panels of a glove box, where workers in an air-line suit replace directly the front acrylic panels in a green house.
Endo, Shinya; Numata, Masami; Ichise, Kenichi; Nishi, Masahiro; Komiya, Tomokazu; Sakuraba, Naotoshi; Usami, Koji; Tomita, Takeshi
Proceedings of 46th Annual Meeting of "Hot Laboratories and Remote Handling" Working Group (HOTLAB 2009) (CD-ROM), 6 Pages, 2009/09
For safety operation and maintenance of the large size glove box, the degraded acrylic panels of the box must be replaced by the new panels. As the conventional replacement technique, the decontamination of the glove box and installation of isolation tent are necessary to prevent the leak of contamination, because airtight condition of the box is broken down during replacement process. Therefore, the prerequisite works are required considerable manpower. The new replacement technique using bag-in / bag-out method was developed by JAEA. In this technique, for keeping the airtight condition of the box, the inside of degraded panel is covered with an airtight panel and the outside is covered over the large bag which is used to replace the acrylic panels. As the benefits of this technique, the prerequisite works are not required and the manpower is less than a third of the conventional technique.
Nishi, Tsuyoshi; Ito, Akinori; Takano, Masahide; Numata, Masami; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo
Journal of Nuclear Materials, 377(3), p.467 - 469, 2008/07
Times Cited Count：12 Percentile：61.74(Materials Science, Multidisciplinary)The specific heat capacities of NpN and AmN were determined by the drop calorimetry method. The NpN and AmN samples were prepared by the carbothermic reduction of the respective dioxides. The specific heat capacity of NpN obtained was in good agreement with the reported values in the temperature range from 334 to 1067 K, which was close to those of UN and PuN. The specific heat capacity of AmN was obtained experimentally for the first time, which was slightly smaller than those of UN, NpN and PuN in the temperature range from 354 to 1071 K.
Kato, Chiaki; Motooka, Takafumi; Numata, Masami; Endo, Shinya; Yamamoto, Masahiro
Structural Materials for Innovative Nuclear Systems (SMINS), p.439 - 447, 2008/07
Corrosion of a nuclear fuel reprocessing plant is also important problem in either current or an advanced nuclear fuel reprocessing system. In this process, nitric acid solution is used to dissolve spent nuclear fuels and solvent extraction method is used to separate U, Pu and actinoid elements. It will be much severer corrosive environment. In this paper, an effect of neptunium ions on corrosion of ultra low carbon Type 304 stainless steel was investigated. The corrosion tests were conducted in 9 kmol/m
nitric acid solution adding neptunium ions. The results show that neptunium ions promote inter-grainier corrosion of SUS304ULC in nitric acid solution and corrosion rate in heat-transfer condition is larger than that in immersed condition. It is estimated that the oxidise potential of nitric ions increases under heat-transfer condition more than immersion condition in boiling solution. Furthermore, the effect of 
-ray irradiation used 
Co is examined. -ray irradiation decreases corrosion rates and the reason is discussed.
Nishi, Tsuyoshi; Ito, Akinori; Takano, Masahide; Numata, Masami; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo
Journal of Nuclear Materials, 376(1), p.78 - 82, 2008/05
Times Cited Count：33 Percentile：88.13(Materials Science, Multidisciplinary)The thermal diffusivity of neptunium dioxide was measured in the temperature range from 473 to 1473 K by a laser flash method. The thermal diffusivity slightly decreased with increasing temperature in the temperature range investigated. The specific heat capacity of NpO
was measured in the temperature range from 334 to 1071 K by a drop calorimetry method. The specific heat capacity of NpO determined in this study was slightly larger than that of UO and about 7 % smaller than that of PuO. The thermal conductivity of NpO was determined from the thermal diffusivity, the specific heat capacity and the bulk density. It was found that the thermal conductivity of NpO from 873 to 1473 K existed between those of UO and PuO.
Nishi, Tsuyoshi; Takano, Masahide; Ito, Akinori; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo; Numata, Masami
Journal of Nuclear Materials, 373(1-3), p.295 - 298, 2008/02
Times Cited Count：16 Percentile：70.82(Materials Science, Multidisciplinary)The thermal diffusivity of americium oxide was determined in the temperature range from 299 to 1473 K by a laser flash method. The thermal diffusivity of AmO decreased with increasing temperature. The thermal conductivity of AmO was estimated from the measured thermal diffusivity, the specific heat capacity and the bulk density. It was found that the thermal conductivity of AmO decreased with increasing temperature over the temperature range investigated. It was also found that the decrease in O/Am ratio during the thermal diffusivity measurements under vacuum resulted in a slight decrease in thermal conductivity of AmO.
Motooka, Takafumi; Ishikawa, Akiyoshi; Numata, Masami; Endo, Shinya; Itonaga, Fumio; Kiuchi, Kiyoshi; Kizaki, Minoru
JAEA-Research 2007-031, 20 Pages, 2007/03
JAEA-Research-2007-031.pdf:2.0MB
An effect of neptunium ions on corrosion of stainless steel in nitric acid solution was investigated by corrosion tests. Type SUS304L stainless steel was used for the tests. The corrosion tests were conducted in 9kmol/m nitric acid solutions containing neptunium ions, where test specimens were immersed or heat-transferred. As a result, we found that neptunium ions promote corrosion of stainless steels in nitric acid solution. This finding would contribute to modifications of the materials for spent fuel reprocessing process.
Maeda, Toshikatsu; Bamba, Tsunetaka*; Mizuno, Tsuyoshi*; Terakado, Shogo; Kitagawa, Isamu; Numata, Masami
Haikibutsu Gakkai Rombunshi, 17(4), p.271 - 281, 2006/07
no abstracts in English
Endo, Shinya; Usami, Koji; Nakata, Masahito; Fukuda, Takuji*; Numata, Masami; Kizaki, Minoru; Nishino, Yasuharu
Proceedings of 2005 JAEA-KAERI Joint Seminar on Advanced Irradiation and PIE Technologies, p.S2_7_1 - S2_7_11, 2005/11
no abstracts in English
Takano, Masahide; Ito, Akinori; Akabori, Mitsuo; Minato, Kazuo; Numata, Masami
Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), p.2285 - 2291, 2003/00
Stability of AmN and (Am,Zr)N was studied comparatively from the viewpoints of the hydrolytic and evaporative behavior. AmN powder reacted with moisture to form hydroxide Am(OH)
, while the solid solution (Am
Zr
)N remained stable as long as 1000 hours. Stabilization effect of ZrN was found to depend significantly on its mole fraction from the experiments on (Dy,Zr)N. In the oxidation experiments on (Dy,Zr)N by TG-DTA technique, rapid weight gain by the oxidation occurred above 700 K. Effect of ZrN on the stability against oxygen was slight. Nitrogen release by the evaporation of AmN and (AmZr)N in He gas flow was measured by gas chromatography. Evaporation rate constants of AmN were obtained at 1623-1733 K. Although the evaporation rate constant of AmN in the solid solution were lower than those of the pure AmN, the selective evaporation of AmN from the solid slution were recognized, which resulted in a decrease in the Am mole fraction.
Ito, Akinori; Akabori, Mitsuo; Takano, Masahide; Ogawa, Toru; Numata, Masami; Itonaga, Fumio
Journal of Nuclear Science and Technology, 39(Suppl.3), p.737 - 740, 2002/11
no abstracts in English
Cm-
Pu oxide and mononitrideTakano, Masahide; Ito, Akinori; Akabori, Mitsuo; Ogawa, Toru; Numata, Masami; Kizaki, Minoru
Journal of Nuclear Science and Technology, 39(Suppl.3), p.842 - 845, 2002/11
no abstracts in English
Motooka, Takafumi; Numata, Masami; Kiuchi, Kiyoshi
JAERI-Tech 2001-088, 38 Pages, 2002/01
JAERI-Tech-2001-088.pdf:2.78MB
We have been evaluated the safety for corrosion of various metals applied to acid recovery evaporators by the mock-up tests using small scaled equipment and the reference tests in laboratories with small specimens. These tests have been conducted under un-radioactive environment. The environment in practical reprocessing plants has many radioactive species. Therefore, the effect of irradiation on corrosion should be evaluated in detail.In this study, we have developed the corrosion testing equipment, which is employed to simulate environments in the acid recovery evaporators. This report describes the specification of corrosion testing equipment and the results of primary, reference and hot tests.Using the equipment, the corrosion test under heat transfer and irradiation conditions has been carried out for 930 hours in safety. It is expectable that useful corrosion test data in radioactive environment are accumulated with this equipment in future, and help the adequate choice of corrosion test condition in laboratories.
Takano, Masahide; Ito, Akinori; Akabori, Mitsuo; Ogawa, Toru; Numata, Masami; Okamoto, Hisato
Journal of Nuclear Materials, 294(1-2), p.24 - 27, 2001/04
Times Cited Count：13 Percentile：66.91(Materials Science, Multidisciplinary)no abstracts in English
Ogawa, Toru; Minato, Kazuo; Fukuda, Kosaku; ; ; Sekino, Hajime; ; Ito, Tadaharu; ;
Nuclear Technology, 96, p.314 - 322, 1991/12
Times Cited Count：12 Percentile：76.66(Nuclear Science & Technology)no abstracts in English
; ; ; Tobita, Tsutomu; ; ; ; ; ; Iwamoto, K.; et al.
JAERI-M 85-041, 48 Pages, 1985/03
no abstracts in English
kernel of coated fuel particle; ; ; ; Ikawa, Katsuichi
Journal of Nuclear Materials, 135, p.18 - 31, 1985/00
Times Cited Count：13 Percentile：81.94(Materials Science, Multidisciplinary)no abstracts in English
Numata, Masami; Kato, Chiaki; Motooka, Takafumi; Endo, Shinya; Kitagawa, Isamu; Kizaki, Minoru; Yamamoto, Masahiro; Kiuchi, Kiyoshi
no journal, ,
We estimated environment assisted cracking of zirconium such as the unclear fuel dissolver in spent unclear fuel solution and considered the cold simulated solution with substituted similar oxidization ions for trans-uranium (TRU) and fission products (FP) and difference between the cold simulated solution and the hot spent unclear fuel. In addition, we considered radiation effect of ray under irradiation of cobalt-60 to simulate closely the dissolver condition. In this report, we confirmed that the cold simulated solution is appropriate solution to substitute for the spent nuclear fuel solution and radiation of ray doesn't accelerate environment assisted cracking of zirconium.
