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Ikeuchi, Hirotomo
Journal of Nuclear Science and Technology, 59(6), p.768 - 780, 2022/06
Times Cited Count：1 Percentile：29.26(Nuclear Science & Technology)Narukawa, Takafumi
Kaku Nenryo, (54-2), P. 3, 2019/07
no abstracts in English
Mohamad, A.*; Nakajima, Kunihisa; Suzuki, Eriko; Miwa, Shuhei; Osaka, Masahiko; Oishi, Yuji*; Muta, Hiroaki*; Kurosaki, Ken*
Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05
In the accident of Fukushima Daiichi Nuclear Power Station, formation of a volatile SrCl
could have occurred by the sea-water injection into the core. This can cause the release of non-volatile group Sr from the fuel to induce chemical reactions with reactor structural materials, such as stainless steel and Zircaloy (Zry) cladding. Such reactions could cause the changes in distribution of Sr in the reactor. Chemical reactions between Sr species and Zry were therefore investigated experimentally. As the result, it can be said that Sr vapor species were chemically trapped right after the release from fuel. This trapping effect of Sr by Zry-cladding implies a possibility of preferable Sr retention in the oxide phase of debris.
Yamauchi, Akihiro*; Amaya, Masaki
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 7 Pages, 2018/10
Differential scanning calorimetry (DSC) measurements on pre-hydrided cold worked, stress relieved and recrystallized Zry-4 cladding were performed in a temperature range between 50 and 600
C in order to elucidate the effect of final heat treatment at fabrication of Zircaloy-4 (Zry-4) cladding on the terminal solid solubility during the dissolution of zirconium hydrides at heating up (TSSD). Obtained DSC curves and Metallography indicate that the initial state of hydrides affects the dissolution behavior of hydride. The Arrhenius plots of the TSSD temperatures and hydrogen contents obtained from this study revealed that cold worked samples exhibited the largest TSSD and followed by stress relieved and recrystallized samples. The results of this study indicated that the difference in microstructure due to final heat treatment at fabrication of Zry-4 cladding affects the dissolution behavior of hydrides.
Yamazaki, Saishun; Pshenichnikov, A.; Pham, V. H.; Nagae, Yuji; Kurata, Masaki; Tokushima, Kazuyuki*; Aomi, Masaki*; Sakamoto, Kan*
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 8 Pages, 2018/10
It is predictively evaluated that degradation of fuel assembly proceeded in a certain steam-starved condition at the early stage of a SA at 1F unit 2 (BWR). As for PWR fuel assembly, effective steam flow rate was properly indicated by normalizing to a unit of g-HO/sec/rod which is used as an important parameter for evaluating fuel degradation progression. Due to the inhomogeneous configuration of BWR fuel assembly, the difference of Zry oxidation and hydrogen uptake between the inside and outside of the channel box cannot be properly evaluated by this normalization. Instead of g-HO/sec/rod, proper evaluation unit for BWR configuration is necessary. To accumulate Zry oxidation and hydrogen uptake data for steam-starved conditions, high temperature oxidation tests were performed using a simulated BWR fuel bundle sample. The use of equivalent diameter of the cross section of BWR fuel assembly was proposed for normalization of effective steam flow rate.
Narukawa, Takafumi
Kaku Nenryo, (53-2), P. 5, 2018/08
no abstracts in English
Matsumoto, Yoshinobu*; Do, Thi-Mai-Dung*; Inoue, Masao; Nagaishi, Ryuji; Ogawa, Toru
Journal of Nuclear Science and Technology, 52(10), p.1303 - 1307, 2015/10
Times Cited Count：4 Percentile：32.95(Nuclear Science & Technology)Effects of zirconium oxides and oxidation products of zircaloy-4 on water radiolysis were investigated to predict the hydrogen generation from the water-immersed debris after a severe accident of a nuclear power plant. Observed yields of hydrogen in water containing the oxides were measured as a function of their weight fractions. Assuming that energies of Co-60 
-ray deposited to water and the oxides brought about the water radiolysis to generate hydrogen independently, the radiolysis showed an additional term of hydrogen generation due to the energy deposition to the oxides. This term seemed to be dependent on the specific surface area or particle size of oxides, but not on the crystal structure of oxides in our experimental results. The oxides in distilled water gave the strong enhancement of term. The enhancement tended to saturate with increasing the weight fraction of oxides and was not apparent in the seawater.
Sugiyama, Tomoyuki; Nagase, Fumihisa; Fuketa, Toyoshi
Proceedings of 2005 Water Reactor Fuel Performance Meeting (CD-ROM), p.912 - 932, 2005/10
High burnup fuel cladding can fail due to mechanical interaction with expanding fuel pellet under reactivity initiated accident (RIA) conditions. In order to evaluate the cladding failure limit, investigations to modify ring tensile test have been performed to measure mechanical properties of Zircaloy cladding properly. JAERI developed the test method and geometry minimizing undesirable effects of friction and bending moment in the specimen. Using the modified test method, mechanical properties of unirradiated Zircaloy-4 cladding were evaluated as functions of hydrogen concentration and temperature. For hydrogen concentrations above 700 ppm, obvious increase of ductility is observed with the temperature increase from 300 to 473 K. For hydrogen concentrations below 500 ppm, on the other hand, temperature dependence of ductility is relatively small in the present temperature range from 300 to 573 K.
Yasuda, Ryo; Nakata, Masahito; Matsubayashi, Masahito; Harada, Katsuya; Hatakeyama, Yuichi; Amano, Hidetoshi
Journal of Nuclear Materials, 320(3), p.223 - 230, 2003/08
Times Cited Count：15 Percentile：68.99(Materials Science, Multidisciplinary)Neutron radiography is one of effective tools to determine hydrided region in Zircaloy cladding tubes. In this work, the practicability of the neutron radiography for hydrogen analysis is further investigated by using standard samples with known hydrogen concentration. Local hydrogen concentration in hydrided Zircaloy tube is quantitatively estimated using the standard samples by neutron imaging plate (NIP) method. The local area is equivalent to a picture element in the image; e.g., 0.1mm
0.1mm. In addition, contribution of an oxide film in the tubes to the images is investigated using oxidized samples with hydrides or no hydride. In NIP images of oxidized tube no oxide film was recognized. Numerical image analysis also shows no effect of the oxide film on the image. These results show that the influence of oxygen on image contrast can be neglected when hydrogen analysis is performed on the Zircaloy tube with oxide film and hydrides by NIP method.
Yasuda, Ryo; Matsubayashi, Masahito; Nakata, Masahito; Harada, Katsuya
Journal of Nuclear Materials, 302(2-3), p.156 - 164, 2002/04
Times Cited Count：28 Percentile：84.11(Materials Science, Multidisciplinary)no abstracts in English
Kitano, Koji*; Fuketa, Toyoshi; Uetsuka, Hiroshi
JAERI-Research 2001-041, 24 Pages, 2001/08
JAERI-Research-2001-041.pdf:2.75MB
no abstracts in English
Uetsuka, Hiroshi
Saishin Kaku Nenryo Kogaku; Kodoka No Genjo To Tembo, p.156 - 162, 2001/06
no abstracts in English
Yasuda, Ryo; Nakata, Masahito; Matsubayashi, Masahito; Harada, Katsuya; Ando, Hitoshi*
JAERI-Tech 2000-082, 38 Pages, 2001/02
JAERI-Tech-2000-082.pdf:7.79MB
no abstracts in English
Arai, Yasuo; Nakajima, Kunihisa
Journal of Nuclear Materials, 281(2-3), p.244 - 247, 2000/10
Times Cited Count：40 Percentile：92.08(Materials Science, Multidisciplinary)no abstracts in English
Kuroda, Masatoshi*; Yoshioka, Kunihiko*; Yamanaka, Shinsuke*; Anada, Hiroyuki*; Nagase, Fumihisa; Uetsuka, Hiroshi
Journal of Nuclear Science and Technology, 37(8), p.670 - 675, 2000/08
no abstracts in English
Nagase, Fumihisa; Otomo, Takashi; Tanimoto, Masataka*; Uetsuka, Hiroshi
Proceedings of the 2000 International Topical Meeting on LWR Fuel Performance (CD-ROM), 15 Pages, 2000/04
no abstracts in English
*; Fujiwara, Masayuki*
JNC TJ8430 2000-001, 55 Pages, 2000/03
JNC-TJ8430-2000-001.pdf:4.82MB
no abstracts in English
