Long term monitoring and evaluation of the excavation damaged zone induced around the wall of the shaft applying optical fiber sensor (Cooperative research)

Hata, Koji*; Niunoya, Sumio*; Uyama, Masao*; Nakaoka, Kenichi*; Fukaya, Masaaki*; Aoyagi, Kazuhei; Sakurai, Akitaka; Tanai, Kenji

JAEA-Research 2020-010, 142 Pages, 2020/11

JAEA-Research-2020-010.pdf:13.74MB
JAEA-Research-2020-010-appendix(DVD-ROM).zip:149.9MB

In the geological disposal study of high-level radioactive waste, it is suggested that the excavation damaged zone (EDZ) which is created around a tunnel by the excavation will be possible to be one of the critical path of radionuclides. Especially, the progress of cracks in and around the EDZ with time affects the safety assessment of geological disposal and it is important to understand the hydraulic change due to the progress of cracks in and around EDZ. In this collaborative research, monitoring tools made by Obayashi Corporation were installed at a total of 9 locations in the three boreholes near the depth of 370 m of East Shaft at the Horonobe Underground Research Laboratory constructed in the Neogene sedimentary rock. The monitoring tool consists of one set of "optical AE sensor" for measuring of the mechanical rock mass behavior and "optical pore water pressure sensor and optical temperature sensor" for measuring of groundwater behavior. This tool was made for the purpose of selecting and analyzing of AE signal waveforms due to rock fracture during and after excavation of the target deep shaft. As a result of analyzing various measurement data including AE signal waveforms, it is able to understand the information on short-term or long-term progress of cracks in and around EDZ during and after excavation in the deep shaft. In the future, it will be possible to carry out a study that contributes to the long-term stability evaluation of EDZ in sedimentary rocks in the deep part of the Horonobe Underground Research Laboratory by evaluation based on these analytical data.

Research and development of thick rubber bearing for SFR; Aging properties tests of semi full-scale thick rubber bearing

Watakabe, Tomoyoshi; Yamamoto, Tomohiko; Fukasawa, Tsuyoshi*; Okamura, Shigeki*; Somaki, Takahiro*; Morobishi, Ryota*; Sakurai, Yu*; Kato, Koji*

Nihon Kikai Gakkai Rombunshu (Internet), 83(850), p.16-00444_1 - 16-00444_14, 2017/06

https://doi.org/10.1299/transjsme.16-00444

A seismic isolation system composed of a thick rubber bearing and an oil damper has been developed for Sodium-Cooled Fast Reactor. This paper focused on the aging properties of thick rubber bearings, such as basic mechanical properties and ultimate strength. Aging of the rubber bearings was reproduced using thermal degradation based on Arrhenius law.

Assembly study for JT-60SA tokamak

Shibanuma, Kiyoshi; Arai, Takashi; Hasegawa, Koichi; Hoshi, Ryo; Kamiya, Koji; Kawashima, Hisato; Kubo, Hirotaka; Masaki, Kei; Saeki, Hisashi; Sakurai, Shinji; et al.

Fusion Engineering and Design, 88(6-8), p.705 - 710, 2013/10

https://doi.org/10.1016/j.fusengdes.2012.12.011

Establishment of reassembly technique of capsule type irradiation rig

Ichikawa, Shoichi; Abe, Kazuyuki; Haga, Hiroyuki; Kajima, Hisashi*; Sakurai, Satoshi*; Katsuyama, Kozo; Maeda, Koji; Nishinoiri, Kenji

JAEA-Technology 2011-032, 46 Pages, 2012/01

JAEA-Technology-2011-032.pdf:8.46MB

The assembly technique to the capsular irradiation rig newly developed was established. In the irradiation examination, the assembling disassembling and reassembling to PFB110 "B11(1), B11(2)" and PFB140 "B14" that built in Am-MOX fuel pin was achieved. The reassembly technique by recycling the irradiation material was established in the assembly of B11(2). This time, the assembly and disassembly of B11 (1) were reported. Moreover, the assembly of B14 which improved the assembly technology of B11 (1) was reported.

Multistep lattice-voxel method utilizing lattice function for Monte-Carlo treatment planning with pixel based voxel model

Kumada, Hiroaki*; Saito, Kimiaki; Nakamura, Takemi; Sakae, Takeji*; Sakurai, Hideyuki*; Matsumura, Akira*; Ono, Koji*

Proceedings of 14th International Congress on Neutron Capture Therapy (ICNCT-14) (CD-ROM), p.238 - 241, 2010/10

Conceptual design of the SlimCS fusion DEMO reactor

Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.

JAEA-Research 2010-019, 194 Pages, 2010/08

JAEA-Research-2010-019-01.pdf:48.47MB
JAEA-Research-2010-019-02.pdf:19.4MB

This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.

Ferritic insertion for reduction of toroidal magnetic field ripple on JT-60U

Shinohara, Koji; Sakurai, Shinji; Ishikawa, Masao; Tsuzuki, Kazuhiro*; Suzuki, Yutaka; Masaki, Kei; Naito, Osamu; Kurihara, Kenichi; Suzuki, Takahiro; Koide, Yoshihiko; et al.

Nuclear Fusion, 47(8), p.997 - 1004, 2007/08

https://doi.org/10.1088/0029-5515/47/8/034

Ferritic steel plates have been installed to improve the energetic ion confinement through reducing a toroidal magnetic field ripple. Aiming at cost-effective installation, orbit following calculations of energetic ions were performed for a design of ferritic installation on JT-60U by using the Fully three Dimensional magnetic field Orbit-Following Monte-Carlo (F3D OFMC) code. The installed ferritic steel adds the non-linear magnetic field on magnetic sensors for a plasma control and an equilibrium calculation. The code for a real-time control has been modified to take into account the magnetic field by ferritic steel. The plasma operation was successfully resumed and a real-time plasma control was successfully carried out after usual preparation processes. The heat load measurement indicates the improved confinement of energetic ions. These results are important for practical application of ferritic steel which is a leading candidate of a structural material on a demo reactor.

Development of a real-time thermal neutron monitor and its clinical application

Ishikawa, Masayori*; Ono, Koji*; Matsumura, Akira*; Yamamoto, Tetsuya*; Hiratsuka, Junichi*; Miyatake, Shinichi*; Kato, Itsuro*; Sakurai, Yoshinori*; Kobayashi, Toru*; Kumada, Hiroaki; et al.

Proceedings of 12th International Congress on Neutron Capture Therapy (ICNCT-12), p.397 - 400, 2006/10

An ultraminiature thermal neutron monitor which was named SOF detector (Scintillator with Optical Fiber detector) had been developed for BNCT treatment. We had been experienced 15 clinical trials using SOF detector until the end of 2005, some measurements got good results, and some got unacceptable results. One reason of the unacceptable results was due to dislocation of the detector during treatment. This is because it is difficult to fix the SOF detector on patient's skin without strong sticker. To overcome this problem, a loop-type SOF probe was developed. By using the loop-type SOF detector, fixing on the patient's skin was much easier.

Orbit following calculation of energetic ions in the design of ferritic insertion in the JT-60U

Shinohara, Koji; Suzuki, Yutaka; Sakurai, Shinji; Masaki, Kei; Fujita, Takaaki; Miura, Yukitoshi

Plasma and Fusion Research (Internet), 1(2), p.007_1 - 007_8, 2006/02

For the further pursuit of the steady-state advanced tokamak research, the ferritic insertion was proposed to reduce the toroidal field (TF) ripple. The reduction of energetic ion loss due to the TF ripple reduction brings: (1)the enhancement of the heating and current drive effective efficiency, (2)the extended pulse length and the improved efficiency of RF injection due to the reduced heat flux on antennas and improved coupling between antennas and a plasma, (3)the availability of a wall stabilization without losing heating power, and (4)the possibility of an enhanced availability of the rotation control to improve the MHD stability and transport. The design work of ferritic inserts was carried out aiming at an effective, machine-safe, and short-term installation. Here, the design work for ferritic inserts is described from the viewpoint of the behavior of energetic ions. The confinement of energetic ions and the absence of the unfavorable heat flux on the first wall was assessed by using the Fully three Dimensional magnetic field OFMC code, which was developed for a ferrite insert program in JFT-2M. In the final design, the absorbed power in the neutral beam injection is improved by a factor of about 1.3 in a large volume plasma with Bt0 = 1.9T.

Gamow-Teller decay of the nucleus Cr

Onishi, Takeo*; Gelberg, A.*; Sakurai, Hiroyoshi*; Yoneda, Kenichiro*; Aoi, Nori*; Imai, Nobuaki*; Baba, Hidetada*; Von Brentano, P.*; Fukuda, Naoki*; Ichikawa, Yuichi*; et al.

Physical Review C, 72(2), p.024308_1 - 024308_7, 2005/08

https://doi.org/10.1103/PhysRevC.72.024308

no abstracts in English