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Journal Articles

A Consideration on the use of shear waves to improve the sensitivity of an optical ultrasonic sensor for under-sodium viewers

Saruta, Koichi; Shirahama, Takuma*; Yamaguchi, Toshihiko; Ueda, Masashi

E-Journal of Advanced Maintenance (Internet), 10(2), p.1 - 8, 2018/08

Journal Articles

Journal Articles

Multi-point strain measurement using FBG-OTDR optical fiber sensor

Saruta, Koichi; Kobayashi, Takao*

EUR-26577-EN, p.490 - 496, 2014/07

Journal Articles

Development of a health monitoring system using a thermal-resistant fiber Bragg grating for fast reactor power plants; Performance evaluation of a thermal-resistant FBG for strain measurement

Saruta, Koichi; Tsukimori, Kazuyuki; Shimada, Yukihiro; Nishimura, Akihiko; Kobayashi, Takao*

Nihon Hozen Gakkai Dai-6-Kai Gakujutsu Koenkai Yoshishu, p.219 - 222, 2009/08

A thermal-resistant fiber Bragg grating (FBG) fabricated by femtosecond laser processing was examined to evaluate the performance as a strain sensor, compared with a conventional FBG sensor. Each FBG was affixed on a stainless-steel beam along with a strain gauge to measure the Bragg wavelength shift as a function of strain. We used the intensity of the reflection spectra from the FBGs as a weighting factor to determine the Bragg wavelengths. Although the strain sensitivity for the thermal-resistant FBG was found to be 0.34 pm/$$mu$$$$varepsilon$$, a measurement accuracy of $$pm$$3$$mu$$$$varepsilon$$ was able to be achieved by employing the Bragg wavelength determination algorithm, which was comparable to a measurement accuracy of $$pm$$2$$mu$$$$varepsilon$$ for the conventional FBG sensor.

JAEA Reports

Countermeasure to prevent temperature rise of primary upper shield in HTTR; Performance test of countermeasures under actural core configuration

Tachibana, Yukio; Hontani, Koji*; Kojima, Takao; Takeda, Takeshi; Emori, Koichi; Saruta, Toru; Iyoku, Tatsuo; Kunitomi, Kazuhiko

JAERI-Tech 2000-026, p.61 - 0, 2000/03

JAERI-Tech-2000-026.pdf:2.18MB

no abstracts in English

JAEA Reports

Impurity measurement test of HTTR; At the commissioning tests

Sakaba, Nariaki; Emori, Koichi; Saruta, Toru

JAERI-Tech 99-072, p.125 - 0, 1999/10

JAERI-Tech-99-072.pdf:5.85MB

no abstracts in English

Oral presentation

Development of vibration and deformation monitoring techniques for high temperature structures by heat-resistant FBG, 4

Shimada, Yukihiro; Nishimura, Akihiko; Saruta, Koichi; Tsukimori, Kazuyuki; Yoshikawa, Masanari*; Kobayashi, Takao*

no journal, , 

A Fiber Bragg Grating (FBG) sensor is a powerful method of vibration of a structure and the leading methods of carrying out modification monitoring. However, since the FBG sensor which exists now does not have high temperature resistance, use in a high temperature plant is difficult. In recent years, the micro fabrication to high embrittlement materials, such as quartz, became possible by development of ultra fast pulsed laser. We performed the non-heat laser processing to the optical fiber using femto-second pulsed laser.

Oral presentation

Fabrication and performance assessment of FBG sensor with pulse laser processing

Shimada, Yukihiro; Nishimura, Akihiko; Saruta, Koichi; Tsukimori, Kazuyuki; Kobayashi, Takao*

no journal, , 

Fiber Bragg Grating (FBG) is the periodic refractive-index structure in an optical fiber core, where the light of a specific wavelength is reflected. It can be used as temperature or a distorted sensor by measuring change of the reflective wavelength of FBG. We processed FBG using a Chirped Pulse Amplification titanium sapphire laser. As a result, we confirmed produced FBG had the tolerance at the high temperature. The heat-resistant FBG sensor developed using ultra-short pulse laser processing will contribute to the surveillance of power plants.

Oral presentation

Processing of heat-resistant fiber Bragg grating using femto-second pulse laser by point-by-point method

Shimada, Yukihiro; Nishimura, Akihiko; Saruta, Koichi; Tsukimori, Kazuyuki; Kobayashi, Takao*

no journal, , 

Fiber Bragg grating (FBG) sensor system is a powerful method of detecting strain and temperature of a structure, and is put in practical use widely. However, a general FBG sensor system has a fault without tolerance in high temperature. We performed the micro fabrication in the silica fiber by the point by point method using femtosecond pulse laser. As a result, we succeeded in heat-resistant creation of FBG.

Oral presentation

Assignment of monitoring system for high-temperature structure using heat resistant fiber Bragg grating

Shimada, Yukihiro; Nishimura, Akihiko; Saruta, Koichi; Tsukimori, Kazuyuki; Kobayashi, Takao*

no journal, , 

The fiber Bragg grating sensor with heat-resistance in microfabrication that used the ultrafast pulse laser was produced. The sensing system optimized to the characteristic of the produced sensor was designed, produced, and the distortion of piping in a mock plant and the examination of the vibration measurement were done. The result of current development is summarized, and the development task in the future is clarified.

Oral presentation

Fundamental study of acoustic emission in rotating machines by non-contact measurement using laser interferometer

Ota, Yasufumi; Saruta, Koichi; Noguchi, Shotaro; Ueda, Masashi

no journal, , 

no abstracts in English

Oral presentation

FBG-OTDR optical fiber sensor; Application to multi-point strain measurement

Saruta, Koichi

no journal, , 

no abstracts in English

Oral presentation

Sensitivity characteristics of optical ultrasonic sensors using a metallic membrane for under-sodium inspection

Saruta, Koichi; Yamaguchi, Toshihiko; Ueda, Masashi

no journal, , 

no abstracts in English

Oral presentation

R&D program of maintenance technologies for the fast reactors in the sodium engineering research facility

Ueda, Masashi; Yamaguchi, Toshihiko; Saruta, Koichi

no journal, , 

no abstracts in English

Oral presentation

The R&D Programs of Maintenance Technology for FBR Monju Using the Sodium Engineering Research Facility

Saruta, Koichi; Yamaguchi, Toshihiko; Ueda, Masashi

no journal, , 

Oral presentation

Research and development to improve laser cutting process by an adaptive control system; Study on control method for laser cutting using optical signal by dross

Mizutani, Haruki; Saruta, Koichi; Kamei, Naomitsu; Muramatsu, Toshiharu

no journal, , 

no abstracts in English

Oral presentation

Development of laser decontamination technology using high-speed laser spot swept high-power density fiber laser

Kosuge, Atsushi; Minehara, Eisuke*; Saruta, Koichi

no journal, , 

Decontamination is required when disposing of equipment contaminated by the accident at TEPCO's Fukushima Daiichi Nuclear Power Station. The decontamination method generally used at present has a problem that a large amount of secondary waste is generated. Decontamination using a laser is non-contact and can significantly suppress the generation of secondary waste. In this study, we used a method of instantly evaporating and peeling using a continuous wave fiber laser, and observed the time change of peeling of the metal surface using a high-speed camera.

Oral presentation

Development of a CW fiber laser decontamination using high-speed scanning of a high-power density laser beam, 1; Understanding the laser decontamination mechanism

Kosuge, Atsushi; Minehara, Eisuke*; Saruta, Koichi

no journal, , 

Decontamination is required when disposing of equipment contaminated by the accident at TEPCO's Fukushima Daiichi Nuclear Power Plant. The decontamination method generally used at present has a problem that a large amount of secondary waste is generated. Decontamination using a laser is non-contact and can significantly suppress the generation of secondary waste. In this study, we used a method of instantly evaporating and peeling using a continuous wave fiber laser, and observed the time change of peeling of the metal surface using a high-speed camera. Furthermore, a decontamination test was conducted using this laser decontamination method for the parts of the analyzer installed in Minamisoma City, Fukushima Prefecture, which was contaminated with radioactive substances.

21 (Records 1-20 displayed on this page)