Development of the multi-level displacement sensor using Fiber Bragg Gratings (FBG)

Sanada, Hiroyuki; Sugita, Yutaka; Daimaru, Shuji; Matsui, Hiroya; Kashiwai, Yoshio*

Journal of MMIJ, 126(10,11), p.569 - 576, 2010/10

When the structures such as rock slopes, underground caverns for the geological disposal of high level radioactive waste and underground power plants are constructed, the potential for displacement and damage in the surrounding rock mass is increased due to stress concentration and creep phenomenon. Therefore, the long-term monitoring of rock stability for construction of rock cavern and slopes is important to maintain stability of rock structures. Recently, development of sensors that use optical fiber have expanded mainly in the field of civil engineering and, in rock and soil mechanics, since several parameters such as temperature, strain, pressure, pH etc. can be obtained by using backscattered light in optical fibers. Additionally, some important advantages using optical fiber are its high resistance to the electric insulation failure, long-term endurance and ability to transmit data over long distances. This paper describes development of a multiple-type displacement sensor using FBG, which has potential for the long-term durability and high accuracy. Laboratory tests were carried out to investigate the relational expression computed from the relationship of the variation in the Bragg wavelength, temperature and displacement. Accuracy of the prototype developed in this research is better than 0.5% or 1/100 mm. The in situ tests involving long-term monitoring using boreholes were conducted to confirm the workability and applicability of the prototype. From the results of the in situ tests, workability is equivalent to the extensometers usually used for long-term monitoring, and the displacement computed from the variation of Bragg wavelength is almost equal to the artificially induced deformation.

Development of optical fiber displacement sensor for bedrocks (The Second year)

Kashiwai, Yoshio*; Sanada, Hiroyuki; Matsui, Hiroya

JAEA-Technology 2008-046, 52 Pages, 2009/07

JAEA-Technology-2008-046.pdf:37.92MB

This work was performed by Taisei Kiso Sekkei Co., Ltd. under contract with Japan Atomic Energy Agency. The objective of this work is development of multiple stage optical fiber displacement sensors for the deformation monitoring of shafts and horizontal tunnels at the Phase 2 of Horonobe Underground Research Laboratory project. In previous year, the feasibility study was done for developing the multiple stage optical fiber displacement sensors of ten stages or more for the boreholes which diameter are 66 mm. Based on this feasibility study, two types of prototype for field measurement were developed and evaluated by laboratory tests. These prototypes were modified and field test equipments were developed which were consisted of 4 pieces of shallow part sensors and 2 pieces of deep part sensors.

Test results of the third Japanese SULTAN sample

Matsui, Kunihiro; Isono, Takaaki; Nunoya, Yoshihiko; Hemmi, Tsutomu; Okui, Yoshio*; Oshikiri, Masayuki; Koizumi, Norikiyo; Takahashi, Yoshikazu; Okuno, Kiyoshi; Stepanov, B.*; et al.

IEEE Transactions on Applied Superconductivity, 19(3), p.1470 - 1473, 2009/06

https://doi.org/10.1109/TASC.2009.2017696

Conductor procurement for ITER Toroidal Field (TF) coils in Japan has just stated in the spring of 2008 under agreement with ITER organization. Before the activity, each NbSn conductor must be tested at SULTAN facility in Switzerland for qualification of the conductor. The TF conductor is cable-in-conduit type with about 40 mm outer diameter and is composed of 900 NbSn strands, 522 Cu strands, a central spiral and a 316LN tube. Required performance of the conductor is Tcs of 5.7 K at 68 kA and 11.3 T, which is operating condition of TF coils. Japan has four NbSn strand suppliers for ITER and two of them were already tested as Japanese 1st and 2nd SULTAN samples. This paper shows test results of 3rd Japanese SULTAN sample using NbSn strands fabricated by resting two suppliers.

Origin of the monoclinic-to-monoclinic phase transition and evidence for the centrosymmetric crystal structure of BiMnO

Belik, A. A.*; Iikubo, Satoshi; Yokosawa, Tadahiro*; Kodama, Katsuaki; Igawa, Naoki; Shamoto, Shinichi; Azuma, Masaki*; Takano, Mikio*; Kimoto, Koji*; Matsui, Yoshio*; et al.

Journal of the American Chemical Society, 129(4), p.971 - 977, 2007/01

https://doi.org/10.1021/ja0664032

Structural properties of polycrystalline single-phased BiMnO samples prepared at 6 GPa and 1383 K have been studied by selected area electron diffraction (SAED), convergent beam electron diffraction (CBED), and the Rietveld method using neutron diffraction data measured at 300 and 550 K. The SAED and CBED data showed that BiMnO crystallizes in the centrosymmetric space group C2/c at 300 K. The analysis of Mn-O bond lengths suggested that the orbital order present in BiMnO at 300 K melts above T= 474 K. The phase transition at 474 K is of the first order and accompanied by a jump of magnetization and small changes of the effective magnetic moment and Weiss temperature.

Action in radiation protection to new national radiological regulations; Practice in radiation control

Matsui, Hiroshi; Ikezawa, Yoshio

Firumu Bajji Nyusu, 0(161), p.7 - 10, 1990/05

no abstracts in English

Mixing of duct air for the representative air sampling in in-situ testing of high efficiency particulate air filters

Matsui, Hiroshi; Ikezawa, Yoshio; Yoshida, Yoshikazu*; *; *; *; *

Aerosols: Science,Industry,Health and Environment,Vol. 2, p.720 - 723, 1990/00

no abstracts in English

Dispersion and resuspension factors of radioactive dusts derived from air monitoring data in JAERI

Matsui, Hiroshi; Ikezawa, Yoshio; ; ; Onodera, Junichi; ; ; Yoshida, Yoshikazu*

7th Int. Congress of the IRPA, Radiation Protection Practice, Vol. 2, p.673 - 676, 1988/00

no abstracts in English

Radiation control technology applicable to the JPDR decommissioning

Ikezawa, Yoshio; Onodera, Junichi; ; Ashikagaya, Yoshinobu; Matsui, Hiroshi

CONF-871018-Vol.2, p.5-104 - 5-113, 1987/00

no abstracts in English

Development of borehole multiple deformation sensor system

Kashiwai, Yoshio*; Daimaru, Shuji*; Sanada, Hiroyuki; Matsui, Hiroya

no journal, , 

Progress of procurement of ITER TF conductor and resutls of SULTAN test

Isono, Takaaki; Matsui, Kunihiro; Okui, Yoshio*; Seo, Kazutaka; Koizumi, Norikiyo; Takahashi, Yoshikazu; Okuno, Kiyoshi

no journal, , 

ITER TF conductors will be procured by 6 parties, which are Japan, EU, Korea, Russia, US and China. Japan will procure 25% (4.75 coils) of the TF conductors. 100 tons of NbSn strands will be procured by JA for the TF conductors and total length of the conductor shall be 22 km. ITER organization and JAEA have signed agreement to procure the TF conductor last November. JAEA separated the procurement into three categories, which are strand, cable and conductor procurements. Before the procurement, JAEA has evaluated performance of 4 kinds of full size conductors, each of which uses NbSn strands fabricated by respective Japanese company. Test results of 2 kinds of conductors were presented last year. This time, test results of other conductors will be presented.