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Cl in soil near the Fukushima Dai-ichi Nuclear Power PlantOta, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Honda, Maki*; Hosoya, Seiji*; Takano, Kenta*; et al.
JAEA-Conf 2018-002, p.99 - 102, 2019/02
no abstracts in English
Shibata, Taiju; Mizuta, Naoki; Sumita, Junya; Sakaba, Nariaki; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; et al.
Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 7 Pages, 2018/10
Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor (HTGR). Oxidation damage on the graphite components in air ingress accident is a crucial issue for the safety point of view. SiC coating on graphite surface is a possible technique to enhance oxidation resistance. However, it is important to confirm the integrity of this material against high temperature and neutron irradiation for the application of the in-core components. JAEA and Japanese graphite companies carried out the R&D to develop the oxidation-resistant graphite. JAEA and INP investigated the irradiation effects on the oxidation-resistant graphite by using a framework of ISTC partner project. This paper describes the results of post irradiation experiment about the neutron irradiated SiC-coated oxidation-resistant graphite. A brand of oxidation-resistant graphite shows excellent performance against oxidation test after the irradiation.
Mizuta, Naoki; Sumita, Junya; Shibata, Taiju; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Sakaba, Nariaki
Tanso Zairyo Kagaku No Shinten; Nihon Gakutsu Shinkokai Dai-117-Iinkai 70-Shunen Kinen-Shi, p.161 - 166, 2018/10
To enhance oxidation resistance of graphite material for in-core components of HTGR, JAEA and four Japanese graphite companies; Toyo Tanso, IBIDEN, Tokai Carbon and Nippon Techno-Carbon, are carrying out for development of oxidation-resistant graphite by CVD-SiC coating. This paper describes the outline of neutron irradiation test about the oxidation-resistant graphite by WWR-K reactor of INP, Kazakhstan through an ISTC partner project. Prior to the irradiation test, the oxidation-resistant graphite by CVD-SiC coating of all specimens showed enough oxidation resistance under un-irradiation condition. The neutron irradiation test was already completed and out-of-pile oxidation test will be carried out at the hot-laboratory of WWR-K.
Shibata, Taiju; Sumita, Junya; Sakaba, Nariaki; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; Dyussambayev, D.*; et al.
Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.567 - 571, 2016/11
Graphite are used for the in-core components of HTGR, and it is desirable to enhance oxidation resistance to keep much safety margin. SiC coating is the candidate method for this purpose. JAEA and four Japanese graphite companies are studying to develop oxidation-resistant graphite. Neutron irradiation test was carried out by WWR-K reactor of INP of Kazakhstan through ISTC partner project. The total irradiation cycles of WWR-K operation was 10 cycles by 200 days. Irradiation temperature about 1473 K would be attained. The maximum fast neutron fluence (E 
0.18 MeV) for the capsule irradiated at a central irradiation hole was preliminary calculated as 1.2
10
/m
, and for the capsule at a peripheral irradiation hole as 4.210
/m. Dimension and weight of the irradiated specimens were measured, and outer surface of the specimens were observed by optical microscope. For the irradiated oxidation resistant graphite, out-of-pile oxidation test will be carried out at an experimental laboratory.
Sumita, Junya; Shibata, Taiju; Sakaba, Nariaki; Osaki, Hiroki*; Kato, Hideki*; Fujitsuka, Kunihiro*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; Dyussambayev, D.*; et al.
Proceedings of 7th International Topical Meeting on High Temperature Reactor Technology (HTR 2014) (USB Flash Drive), 7 Pages, 2014/10
Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor(HTGR)which is a graphite-moderated and helium gas-cooled reactor. In the case of air ingress accident in HTGR, SiO
protective layer is formed on the surface of SiC layer in TRISO CFP and oxidation of SiC does not proceed and fission products are retained inside the fuel particle. A new safety concept for the HTGR, called Naturally Safe HTGR, has been recently proposed. To enhance the safety of Naturally Safe HTGR ultimately, it is expected that oxidation-resistant graphite is used for graphite components to prevent the TRISO CFPs and fuel compacts from failure. SiC coating is one of candidate methods for oxidation-resistant graphite. JAEA and four graphite companies launched R&Ds to develop the oxidation-resistant graphite and the International Science and Technology Center(ISTC) partner project with JAEA and INP was launched to investigate the irradiation effects on the oxidation-resistant graphite. To determine grades of the oxidation-resistant graphite which will be adopted as irradiation test, a preliminary oxidation test was carried out. This paper described the results of the preliminary oxidation test, the plan of out-of-pile test, irradiation test and post-irradiation test(PIE)of the oxidation-resistant graphite.
nanocomposite electrocatalyst; An in situ electrochemical X-ray absorption fine structure studyMasuda, Takuya*; Fukumitsu, Hitoshi*; Fugane, Keisuke*; Togasaki, Hirotaka*; Matsumura, Daiju; Tamura, Kazuhisa; Nishihata, Yasuo; Yoshikawa, Hideki*; Kobayashi, Keisuke*; Mori, Toshiyuki*; et al.
Journal of Physical Chemistry C, 116(18), p.10098 - 10102, 2012/05
Times Cited Count：118 Percentile：93.76(Chemistry, Physical)In situ electrochemical X-ray absorption fine structure (XAFS) measurements were performed at the Pt L
and Ce L edges of the Pt-CeO/C catalyst, which was prepared by a combined process of precipitation and coimpregnation methods, as well as at the Pt L edge of the conventional Pt/C catalyst in oxygen-saturated HSO
solution to clarify the role of CeO in the reduction of the overpotential for the oxygen reduction reaction (ORR) at the Pt-CeO nanocomposite compared with the conventional Pt/C catalyst. XAFS measurements clearly show that the enhancement of ORR activity is attributed to the inhibition of Pt oxide formation by the CeO layer, of which Ce
was oxidized to Ce
instead of Pt at the Pt oxide formation potential.
Kurosaki, Yukio*; Yamachi, Hiroshi*; Katsunuma, Yoshio*; Nakata, Masao*; Kuwahara, Hideki*; Yamada, Fumitaka*; Matsushita, Kiyoshi*; Sato, Toshinori*
JAEA-Research 2008-048, 274 Pages, 2008/03
JAEA-Research-2008-048.pdf:10.93MB
A junction space between a super deep shaft and horizontal drifts forms a 3-dimensional geo-structure, which would take a complicated mechanical behavior during a junction excavation. However, a quantitative design method for a deep junction has not yet established. In order to examine a collapse mechanism of super deep shaft junction, we have conducted literature surveys and interview studies concerned with a collapses. Considering the results of investigations with reviews of intellectuals, the collapse mechanism depends on both a construction procedure of shaft junction and a geological condition. On the other hand, where a deep junction intersects faults and/or fractures with a large angle, a collapse called taka-nuke may occur and a numerical studies that can simulate a practical rock mass behavior around a shaft junction should be carry out. We demonstrate finite difference method is most adequate for these simulations with intellectual review.
Takemoto, Masafumi; Nakamura, Hideo; Owada, Akihiko; Osaki, Hideki
JAEA-Research 2006-009, 48 Pages, 2006/03
JAEA-Research-2006-009.pdf:3.8MB
Nitrogen (N)gas used for the pressurization of accumulator (ACC) tanks may flow into the PWR primary system during LOCAs after the ACC coolant injection is completed. Since N gas may travel to and accumulates in reactor vessel top and U-tubes in steam generators (SGs), primary cooling and depressurization via SG secondary-side depressurization would become ineffective because of the degradation of condensation heat transfer in SG U-tubes. Quantitative measurement of gas accumulation is necessary to clarify the influences of gas onto such degradation in the heat transfer and thus the primary depressurization. However, direct measurement method of non-condensable gas concentration in steam has not been established. An apparatus to directly measure gas concentration in high-temperature steam was developed to measure gas concentration in vessel upper head and SG U-tubes during LOCA experiments using ROSA/LSFT. The developed apparatus is primarily composed of zirconia oxygen sensor and turbine meter, enabling to deal with small amount of steam-gas mixture at high temperature when air is used to pressurize ACC tanks instead of N gas. This report describes the developed apparatus and its operation method with several test results for the confirmation of oxygen gas measurement capability and applicability of the apparatus to the ROSA/LSTF experiments.
; *; *; Kunieda, Osamu*; Osaki, Hideki; Anoda, Yoshinari; Kukita, Yutaka
JAERI-Tech 96-004, 74 Pages, 1996/02
no abstracts in English
Yonomoto, Taisuke; *; *; Anoda, Yoshinari; Kukita, Yutaka; ; Ito, Hideo; Osaki, Hideki; ; Nishikizawa, Tomotoshi; et al.
JAERI-M 94-069, 145 Pages, 1994/03
no abstracts in English
; *; Anoda, Yoshinari; Osaki, Hideki; Kukita, Yutaka
JAERI-M 93-221, 131 Pages, 1993/11
no abstracts in English
Kukita, Yutaka; Nakamura, Hideo; *; *; *; Anoda, Yoshinari; Kumamaru, Hiroshige; Suzuki, Mitsuhiro; ; Yonomoto, Taisuke; et al.
JAERI-M 91-040, 122 Pages, 1991/03
no abstracts in English
Kukita, Yutaka; *; *; *; Anoda, Yoshinari; Kumamaru, Hiroshige; Suzuki, Mitsuhiro; ; Yamamoto, Nobuo; Nakamura, Hideo; et al.
JAERI-M 90-039, 122 Pages, 1990/03
no abstracts in English
Kukita, Yutaka; *; *; Anoda, Yoshinari; Kumamaru, Hiroshige; Suzuki, Mitsuhiro; ; Yamamoto, Nobuo; Nakamura, Hideo; Yonomoto, Taisuke; et al.
JAERI-M 89-225, 117 Pages, 1990/01
no abstracts in English
Kukita, Yutaka; *; *; Anoda, Yoshinari; Kumamaru, Hiroshige; Suzuki, Mitsuhiro; ; Yamamoto, Nobuo; Nakamura, Hideo; Yonomoto, Taisuke; et al.
JAERI-M 89-220, 127 Pages, 1990/01
no abstracts in English
Kumamaru, Hiroshige; *; Nakamura, Hideo; Kukita, Yutaka; Koizumi, Yasuo; Anoda, Yoshinari; Suzuki, Mitsuhiro; ; Katayama, Jiro; Yamamoto, Nobuo; et al.
JAERI-M 89-027, 105 Pages, 1989/03
no abstracts in English
Nakamura, Hideo; Owada, Akihiko; Osaki, Hideki
no journal, ,
no abstracts in English
for improvement of oxygen reduction reaction activity on Pt-CeO model electro catalysisFugane, Keisuke*; Mori, Toshiyuki*; Wu, Y. Y.*; Yamamoto, Shunya; Maekawa, Yasunari; Yoshikawa, Hideki*; Yamashita, Yoshiyuki*; Ueda, Shigenori*; Vladimir, M.*; Suzuki, Akira*; et al.
no journal, ,
no abstracts in English
Shibata, Taiju; Sumita, Junya; Nagata, Hiroshi; Saito, Takashi; Tsuchiya, Kunihiko; Sakaba, Nariaki; Osaki, Hiroki*; Kato, Hideki*; Fujitsuka, Kunihiro*; Muto, Takenori*; et al.
no journal, ,
no abstracts in English
Cl in surface soils near the Fukushima Dai-ichi Nuclear Power Plant using accelerator mass spectrometryOta, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Hosoya, Seiji*; Takano, Kenta*; Ochiai, Yuta*; et al.
no journal, ,
no abstracts in English
