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Nemoto, Yoshiyuki; Ishijima, Yasuhiro; Kondo, Keietsu; Fujimura, Yuki; Kaji, Yoshiyuki
Journal of Nuclear Materials, 575, p.154209_1 - 154209_19, 2023/03
Times Cited Count：1 Percentile：29.26(Materials Science, Multidisciplinary)Previous studies had shown that in certain conditions, the rate of oxidation of zirconium (Zr) based alloy fuel cladding is higher in air-steam mixtures than in dry air. In severe accidents in the spent fuel pool and in other air ingress accidents in nuclear power plants, the cladding is likely to be oxidized in an air-steam mixture, which makes it crucial to have an in-depth understanding of the nature of oxidation and its kinetics in that environment. Oxidation tests were conducted at 800
C on Zircaloy-4 specimens in a mix of (air+steam) with various component ratios. Oxidation kinetics, details of the oxide layer, and hydrogen pick-up in the specimen were studied to investigate the mechanism of oxidation in each of these sets of conditions. Zirconium nitride precipitation in the oxide layer during the initial stages of the pre-breakaway oxidation stage and the widespread porous oxide growth on the cladding surface in the latter post-BA oxidation stage are related to the oxidation mechanism in the air-steam mixture. The differences in the mechanism of oxidation of the cladding in dry air and air-steam mixtures are discussed based on the experimental results.
Nemoto, Yoshiyuki; Kaji, Yoshiyuki; Ogawa, Chihiro*; Nakashima, Kazuo*; Tojo, Masayuki*
Proceedings of 2017 Water Reactor Fuel Performance Meeting (WRFPM 2017) (USB Flash Drive), 10 Pages, 2017/09
To cope with the hypothetical severe accident in spent fuel pools (SFPs), it is important to understand the high temperature oxidation behavior of the Zirconium claddings exposed in the air or in the atmosphere of air/steam mixture. In this study, oxidation tests on Zircaloy-2 (Zry2) and Zircaloy-4 (Zry4) short samples were conducted in the atmosphere of air - steam mixture, and mixing ratio was varied to evaluate its influence on the oxidation kinetics in the temperature range from 600 to 1100C. From 900 to 1000C for Zry2, and from 800 to 1000C for Zry4, oxidation rates appeared higher in air - steam mixture than in dry air or in steam without air. This tendency was appeared more evident in post-breakaway transition phase after fracture of dense oxide layer on the surface of specimens. These results suggest importance of the oxidation model development in consideration of the air - steam mixture environment for the SFP accident analysis.
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JNC TN9440 2000-005, 164 Pages, 2000/06
JNC-TN9440-2000-005.pdf:4.51MB
This report summarizes the operating and irradiation data of the experimental reactor "JOYO" 34th cycle, and estimates the 35th cycle irradiation condition. Irradiation tests in the 34th cycle are as follows: (1)C-type irradiation rig (C4F) (a)High burnup perfomance test of advanced austenitic stainless steel cladding fuel pins (in collaboration with France) (2)C-type irradiation rig (C6D) (a)Large diameter fuel pins irradiation tests (3)Absorber Materials Irradiation Rig (AMIR-6) (a)Run to absorber pin's cladding breach (4)Core Materials Irradiation Rig (CMIR-5) (a)Cladding tube materials irradiation tests for "MONJU" (5)Structure Materials Irradiation Rigs (SMIR) (a)Decision of material design base standard of structure materials for prototype reactor and large reactor (6)Upper core structure irradiation Plug Rig (UPR-1-5) (a)Upper core neutron spectrum effect and accelerated irradiation effect (7)SurVeillance un-instrument Irradiation Rig (SVIR) (a)Confirmation of surveillance irradiation condition for "JOYO" (b)Material irradiation tests (in collaboration with universities) The maximum burnup driver assembly "PFD537" reached 68,500MWd/t(pin average).
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JNC TN9440 2000-002, 157 Pages, 2000/02
JNC-TN9440-2000-002.pdf:5.44MB
This report summarizes the operating and irradiation data of the experimental reactor "JOYO" 33rd cycle, and estimates the 34th cycle irradiation condition. Irradiation tests in the 33rd cycle are as follows: (1)B-type irradiation rig (B9) (a)High burn up performance tests of "MONJU" fuel pins, advanced austenitic steel cladding fuel pins, large diameter fuel pins, ferrite steel cladding fuel pins and large diameter annular pellet fuel pins (b)Mixed carbide and nitride fuel pins irradiation tests (in collaboration with JAERI) (2)C-type irradiation rig (C4F) (a)High burn up performance test of advanced austenitic stainless steel cladding fuel pins (in collaboration with France) (3)C-type irradiation rig (C6D) (a)Large diameter fuel pins irradiation tests (4)Absorber Materials Irradiation Rig (AMIR-6) (a)Run to absorber pin's cladding breach (5)Core Materials Irradiation Rig (CMIR-5) (a)Cladding tube materials irradiation tests for "MONJU" (6)Core Materials Irradiation Rig (CMIR-5-1) (a)Core materials irradiation tests (7)Structure Materials Irradiation Rigs(SMIR) (a)Material irradiation tests (in collaboration with universities) (b)Surveillance back up tests for "MONJU" (8)Upper core structure Irradiation Plug Rig (UPR-1-5) (a)Upper core neutron spectrum effect and accelerated irradiation effect. The maximum burnup driver assembly "PFD516" reached 64,300MWd/t (pin average).
; ; *; *; *; Yoshida, Eiichi;
PNC TN9450 91-010, 259 Pages, 1991/10
In order to advancement in materials strength standard on elevated temperature design guide of the FBRs and evaluation method of materials strength behavior, this report are presented about the creep properties of Mod.9Cr-1Mo steels for steam generator, based on the R&D results obtained through the activities of material tests. Contents of the data sheet are as follows; Material : Mod.9Cr-1Mo steels (Base Metal) Plate 7 Heats (F2, F6, F7, F9, F10, NSC1, NSC2) Forging 8 Heats (F4, F5, F8, F11, VIM, ESR, F520, F550) Tube 1 Heats (F3) Test temperature : 450
650C Test method : According to JIS and FBR Metallic Materials Test Method Test environment : In Air and in Sodium Number of deta : 314 points
Nagai, Shuichiro; ; Tobita, Noriyuki; Seki, Masayuki; *; *
PNC TN8410 91-099, 56 Pages, 1991/05
None
*; M.Suzuki*; *; Kondo, Tatsuo
ASME J.Eng.Mater.Technol., 103(10), p.298 - 304, 1981/00
Times Cited Count：31 Percentile：89.56(Engineering, Mechanical)no abstracts in English
Yokoyama, Yutaka*; Umehara, Ryuji*; Tanaka, Norihiko*; Kawaharada, Yoshiyuki*; Kaneko, Tetsuji*; Fujii, Kazumi*; Iwanami, Masaru*; Ishioka, Shinichi*; Kato, Chiaki; Ueno, Fumiyoshi; et al.
no journal, ,
no abstracts in English
Nemoto, Yoshiyuki; Ogawa, Chihiro; Kaji, Yoshiyuki; Nakashima, Kazuo*; Tojo, Masayuki*; Goto, Daisuke*
no journal, ,
To improve the severe accident codes for the analysis of spent fuel pool (SFP) accident with water level decrease, it is necessary to model the air oxidation behavior of the cladding based on experimental data. For the air oxidation modeling, it is necessary to understand the influence of temperature distribution along axial direction of the cladding in SFP accident condition. In addition, it is important to evaluate the influence of oxide film formed on surface of cladding during operation in nuclear power plant. In this study, bare specimens and pre-oxidized specimens of Japanese zircalloy-4 were investigated. Longer specimens of cladding were tested in air with temperature distribution along the axial direction of the cladding simulating the SFP accident condition. Shorter specimens were adopted for tests in thermogravimetry to obtain basic data. Experimental data were compared and the authors discussed on influence of the temperature distribution and oxide film for the air oxidation behavior.
Nemoto, Yoshiyuki
no journal, ,
To evaluate the safety measures for the spent fuel pool accident, it is required to construct the oxidation model of the fuel cladding materials in air environment to upgrade the simulation codes. The author reviews the latest studies and introduce the own research on oxidation behavior of the zircalloy 2 and 4.
Yokoyama, Yutaka*; Umehara, Ryuji*; Kaneko, Tetsuji*; Tanaka, Norihiko*; Kawaharada, Yoshiyuki*; Fujii, Kazumi*; Iwanami, Masaru*; Ishioka, Shinichi*; Kato, Chiaki; Ueno, Fumiyoshi; et al.
no journal, ,
no abstracts in English
Yano, Yasuhide; Tanno, Takashi; Otsuka, Satoshi; Mitsuhara, Masatoshi*; Nakashima, Hideharu*; Toyama, Takeshi*; Onuma, Masato*
no journal, ,
no abstracts in English
Ishibashi, Ryo*; Hirosaka, Kazuma*; Shibata, Masatoshi*; Sasaki, Masana*; Nemoto, Yoshiyuki
no journal, ,
no abstracts in English
Ishibashi, Ryo*; Hirosaka, Kazuma*; Ikegawa, Tomohiko*; Shibata, Masatoshi*; Sasaki, Masana*; Tsuchiya, Akiyuki*; Pham, V. H.; Kurata, Masaki; Nemoto, Yoshiyuki
no journal, ,
no abstracts in English
Nemoto, Yoshiyuki
no journal, ,
no abstracts in English
