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Goto, Minoru; Demachi, Kazuyuki*; Ueta, Shohei; Nakano, Masaaki*; Honda, Masaki*; Tachibana, Yukio; Inaba, Yoshitomo; Aihara, Jun; Fukaya, Yuji; Tsuji, Nobumasa*; et al.
Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.507 - 513, 2015/09
A concept of a plutonium burner HTGR named as Clean Burn, which has a high nuclear proliferation resistance, had been proposed by Japan Atomic Energy Agency. In addition to the high nuclear proliferation resistance, in order to enhance the safety, we propose to introduce PuO
-YSZ TRISO fuel with ZrC coating to the Clean Burn. In this study, we conduct fabrication tests aiming to establish the basic technologies for fabrication of PuO-YSZ TRISO fuel with ZrC coating. Additionally, we conduct a quantitative evaluation of the security for the safety, a design of the fuel and the reactor core, and a safety evaluation for the Clean Burn to confirm the feasibility. This study is conducted by The University of Tokyo, Japan Atomic Energy Agency, Fuji Electric Co., Ltd., and Nuclear Fuel Industries, Ltd. It was started in FY2014 and will be completed in FY2017, and the first year of the implementation was on schedule.
Nakayama, Masashi; Sato, Haruo; Sugita, Yutaka; Ito, Seiji*; Minamide, Masashi*; Kitagawa, Yoshito*
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.51 - 56, 2011/01
In Japan, any high level radioactive waste repository is to be constructed at over 300 m depth below surface. Tunnel support is used for safety during the construction and operation, and shotcrete and concrete lining are used as the tunnel support. Concrete is a composite material comprised of aggregate, cement and various additives. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. Japan Atomic Energy Agency (JAEA) has developed a low alkaline cement, named as HFSC (Highly fly-ash contained silicafume cement), containing over 60wt% of silica-fume (SF) and fly-ash (FA). HFSC was used experimentally as the shotcrete material in construction of part of the 140 m deep gallery in Horonobe URL. The objective of this experiment was to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. HFSC used in this experiment is composed of 40wt% OPC (Ordinary Portland Cement), 20wt% SF, and 40wt% FA. This composition was determined based on mechanical testing of various mixes of the above components. Because of the low OPC content, the strength of HFSC tends to be lower than that of OPC in normal concrete. The total length of tunnel using HFSC shotcrete is about 73 m and about 500 m
of HFSC was used. The workability of HFSC shotcrete was confirmed in this experimental construction.
Yamazaki, Masanao; Sekiya, Yoshitomo; Fujikawa, Daisuke; Kitagawa, Yoshito*
Chika Kukan Shimpojiumu, Rombunshu, 14, p.191 - 196, 2009/01
The shafts and drifts of the Horonobe Underground Research Laboratory Project have been constructed by JAEA. The construction method of shaft is a short step method. The East Shaft of excavation system is the blasting excavation, and the Ventilation Shaft is the machine excavation. At the present, The East Shaft has ended to G.L.-140.5 m and Ventilation Shaft has ended to G.L.-210.5 m at the end of July, 2008. The difference in depth change or a excavation system was analyzed about the excavation time which occupies about 40% of the cycle time of each shaft. This paper reports the outline of the construction track record of the shafts and the result of having analyzed cycle time paying attention to excavation time.
Kojima, Wataru; Yamakami, Mitsunori; Fujikawa, Daisuke; Orukawa, Go*; Kitagawa, Yoshito*; Doi, Takashi*; Saito, Ryosuke*
Doboku Gakkai Heisei-20-Nendo Zenkoku Taikai Dai-63-Kai Nenji Gakujutsu Koenkai Koen Rombunshu, p.453 - 454, 2008/09
no abstracts in English
Kojima, Wataru; Yamakami, Mitsunori; Fujikawa, Daisuke; Kitagawa, Yoshito*; Hagihara, Takeshi*; Saito, Ryosuke*
Doboku Gakkai Heisei-20-Nendo Zenkoku Taikai Dai-63-Kai Nenji Gakujutsu Koenkai Koen Rombunshu, p.455 - 456, 2008/09
no abstracts in English
Kitagawa, Yoshito*; Fujikawa, Daisuke
no journal, ,
no abstracts in English
Noguchi, Akira; Nakayama, Masashi; Kishi, Hirokazu; Kitagawa, Yoshito*; Minamide, Masashi*
no journal, ,
We are researching about the low alkaline cement applying to support of galleries for high-level radioactive waste repositories. In March, 2009, we performed a experiment of shotcrete with low alkaline cement whose proportion of the binder is 40% of ordinary portland cement, 20% of silicafume and the rest 40% of flyash. By selecting the proportion 30% water binder ratio and adding superplasticizer, the slump was 23 cm and compressive strength of the hardened concrete was 38.3 MPa. This proportion satisfied the standard of the support of the Horonobe Underground Research Laboratory whose compressive strength is more than 36 MPa and slump is around 21cm. The rebound ratio of the shotcrete was around 13%. This value is lower than that of ordinary portland cement. So, we can expect to get a better construction environment with this shotcerte. We decided to use this proportion in the in-situ experiment at the 140 m gallery in the Horonobe URL.
Sekiya, Yoshitomo; Kitagawa, Yoshito*; Igarashi, Toshifumi*; Hokora, Hideyuki*
no journal, ,
no abstracts in English
Kitagawa, Yoshito*; Yamazaki, Masanao; Hagihara, Takeshi*; Minamide, Masashi*; Sekiya, Yoshitomo
no journal, ,
no abstracts in English
Yamanishi, Takeshi; Sekiya, Yoshitomo; Suzuki, Tatsuya; Kitagawa, Yoshito*; Saito, Ryosuke*; Yokota, Daisuke*
no journal, ,
no abstracts in English
Yamanishi, Takeshi; Sekiya, Yoshitomo; Sataka, Hiroyuki; Kitagawa, Yoshito*; Kato, Kinya*
no journal, ,
no abstracts in English
Yamanishi, Takeshi; Sekiya, Yoshitomo; Inagaki, Daisuke; Hatsuyama, Yoshihiro*; Kitagawa, Yoshito*
no journal, ,
no abstracts in English
Yamanishi, Takeshi; Sekiya, Yoshitomo; Suzuki, Tatsuya; Kitagawa, Yoshito*; Kato, Kinya*; Saito, Ryosuke*
no journal, ,
no abstracts in English
Kitagawa, Yoshito*; Minamide, Masashi*; Nayuki, Toshinori*; Yamanishi, Takeshi; Sekiya, Yoshitomo; Ito, Seiji; Sato, Haruo; Nakayama, Masashi
no journal, ,
In Japan, any high level radioactive waste repository is to be constructed at over 300m depth below surface. Tunnel support is used for safety during the construction and operation, and shotcrete and concrete lining are used as the tunnel support. Concrete is a composite material comprised of aggregate, cement and various additives. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. Japan Atomic Energy Agency (JAEA) has developed a low alkaline cement, named as HFSC (High fly-ash silicafume cement), containing over 60wt% of silica-fume (SF) and coal ash (FA). JAEA are presently constructing an underground research laboratory (URL) at Horonobe for research and development in the geosciences and repository engineering technology. HFSC was used experimentally as the shotcrete material in construction of part of the 140m deep gallery in Horonobe URL. The objective of this experiment was to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. HFSC used in this experiment is composed of 40wt% OPC (Ordinary Portland Cement), 20wt% SF, and 40wt% FA. This composition was determined based on mechanical testing of various mixes of the above components. Because of the low OPC content, the strength of HFSC tends to be lower than that of OPC in normal concrete. The total length of tunnel using HFSC shotcrete is about 73m and about 500m of HFSC was used. This experimental construction confirmed the workability of HFSC shotcrete. Although several in-situ experiments using low alkaline cement as shotcrete have been performed at a small scale, this application of HFSC at the Horonobe URL is the first full scale application of low alkaline cement in the construction of a URL in the world.
Sekiya, Yoshitomo; Kitagawa, Yoshito*; Igarashi, Toshifumi*; Hokora, Hideyuki*
no journal, ,
no abstracts in English
Sekiya, Yoshitomo; Kitagawa, Yoshito*; Igarashi, Toshifumi*; Hokora, Hideyuki*
no journal, ,
no abstracts in English
Yamanishi, Takeshi; Sekiya, Yoshitomo; Suzuki, Tatsuya; Ito, Seiji; Kitagawa, Yoshito*; Hagihara, Takeshi*; Doi, Takashi*; Saito, Ryosuke*
no journal, ,
no abstracts in English
