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Journal Articles

Development of automated measurement device for low-level radioactive contamination on building surfaces

Tachibana, Mitsuo; Ito, Hirokuni*; Hatakeyama, Mutsuo*; Yanagihara, Satoshi

Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(1), p.120 - 127, 2004/03

The RAPID-1600 was developed to measure a low-level radioactive contamination on building surfaces automatically. The double layered detectors are structured by two gas flow type detectors with a $$beta$$ rays shielding plate between the two detectors and it is horizontally positioned. The lower counter measures $$beta$$ and $$gamma$$ rays and the upper counter measures $$gamma$$ rays. The $$beta$$ rays counting rates are derived by subtracting $$gamma$$ rays counting rates of the upper counter from $$gamma$$ and $$beta$$ rays counting rates of the lower counter. This mechanism results in sensitive to $$beta$$ rays against to low background radiation conditions. The driving unit can move omnidirectionally by controlling two driving wheels individually, and has a capability to correct its position if an orbital error is detected by the self-position identification system. The RAPID-1600 was successfully applied to the actual measurement in the radioisotope production facilities. The RAPID-1600 is expected to be a useful tool for measurement of radioactivity in decommissioning nuclear facilities.

JAEA Reports

Development of measuring device for inner surfaces of embedded piping (Contract research)

Ito, Hirokuni*; Hatakeyama, Mutsuo*; Tachibana, Mitsuo; Yanagihara, Satoshi

JAERI-Tech 2003-012, 34 Pages, 2003/03

JAERI-Tech-2003-012.pdf:2.87MB

The MISE was developed to evaluate low-level radiological contaminations of inner surfaces of piping. The MISE consists of a cylindrically-formed double layered type detector and a piping crawling robot, which were designed and manufactured separately. In measurements of the contaminations, an outer cylindrical detector close to the surface of piping measures $$beta$$-rays and $$gamma$$-rays and an inner cylindrical detector set after a shielding plate for shield of $$beta$$-rays measures $$gamma$$-rays. The $$beta$$-ray counting rates are derived by subtracting $$gamma$$-ray counts measured by the inner detector from $$gamma$$- and $$beta$$-ray counts measured by the outer detector. The robot transports the double layered type detector with observing inner surfaces of piping. The detection limit for the contamination of $$^{60}$$Co was found to be about 0.17Bq/cm$$^{2}$$ with measurement time of 30 seconds. It is expected that 0.2Bq/cm$$^{2}$$ corresponding to clearance level of $$^{60}$$Co (0.4Bq/g) can be evaluated with measurement time of 2 seconds, which is equal to measurement speed of 54m/h.

Journal Articles

Determination of $$^{36}$$Cl in biological shield concrete using pyrohydrolysis and liquid scintillation counting

Ito, Mitsuo; Watanabe, Kazuo; Hatakeyama, Mutsuo; Tachibana, Mitsuo

Analyst, 127(7), p.964 - 966, 2002/06

 Times Cited Count:10 Percentile:32.54(Chemistry, Analytical)

A method for the determination of Cl-36 in biological shield concrete of nuclear reactor was developed. Cl in the concrete sample was extracted quantitatively by pyrohydrolysis at 900 ºC and recovered in Na2CO3 solution for subsequent measurement of Cl-36 by liquid scintillation counting. WO3 was used as an accelerator in the pyrohydrolysis. The Cl extraction procedure was optimized by investigating experimental conditions with the use of ion chromatography and its recovery was evaluated by the analysis of the geochemical reference samples. Detection limit of Cl-36 was 0.02 Bq g-1 for sample weight of 2g. Relative standard deviation was 3 – 7 % for the samples containing 0.5 Bq g-1 levels of 36Cl. The newly developed method was applied to determine Cl-36 in biological shield concrete of the Japan Power Demonstration Reactor.

Journal Articles

Determination of $$^{41}$$Ca in biological-shield concrete by low-energy X-ray spectrometry

Ito, Mitsuo; Watanabe, Kazuo; Hatakeyama, Mutsuo; Tachibana, Mitsuo

Analytical and Bioanalytical Chemistry, 372(5-6), p.532 - 536, 2002/03

 Times Cited Count:15 Percentile:44.09(Biochemical Research Methods)

An X-ray spectrometry method has been developed for the determination of Ca-41 in the biological shield concrete of nuclear reactors. To isolate Ca from other elements, the concrete sample was first decomposed with nitric, hydrofluoric and perchloric acids. Calcium was then separated from other coexisting radionuclides by ion-exchange chromatography and recovered as an oxalate precipitate. X rays at 3.3 keV from Ca-41 in the calcium oxalate pellet were measured. Detection efficiency of the X-ray measurement at 3.3 keV was calculated from those obtained by measuring Fe-55 standard pellets at 5.9 keV using mass absorption coefficients of the calcium oxalate pellet at each X-ray energy value. A lower limit of determination of 8 Bq g-1 was obtained for a sample weight of 1 g.

JAEA Reports

Study on residual radioactive inventory estimation in reactor decommissioning program (Contract research)

Sukegawa, Takenori; Hatakeyama, Mutsuo; Yanagihara, Satoshi

JAERI-Tech 2001-058, 81 Pages, 2001/09

JAERI-Tech-2001-058.pdf:5.98MB

In general, neutron transport and activation calculation codes are used for residual radioactive inventory estimation; however, it is essential to verify calculations by measurement results because of geometrical complexity of the reactor and so on. The comparison between measured and calculated radioactivity in the JPDR core components showed a relatively good agreement (factor of 2), and it was cleared that water content and weight ratio of steel bars to concrete materials significantly influenced the neutron flux distribution in the biological shield (factor of 2-10 error). The measured radioactivity inside of the reactor pressure vessel wall and at the inner part of the biological shield was compared in detail with the calculations to verify the methodology applied to calculations of radioisotope production. Then it was found that the radioactive inventory could be estimated accurately with combination of calculations and measurement of radioactivity in samples and dose rate distribution for planning of dismantling activities.

Journal Articles

Mobile robot with a self-positioning system

Yanagihara, Satoshi; Hatakeyama, Mutsuo; Ito, Hirokuni; Mori, Shunji*; Takagi, Akira*

Advanced Robotics, 15(3), p.293 - 300, 2001/06

 Times Cited Count:1 Percentile:10.67(Robotics)

Automatic measurement of building surface radioactivity must be a useful approach for decommissioning and maintenance activities in nuclear facilities. In particular, in the final step of decommissioning a nuclear power plant, it is essential to confirm that there is no effective radioactivity on building surfaces by measurement. However, experience showed that hands-on measurement using conventional detectors requires a great deal of labor-hours for all building surfaces in relatively large facilities. To realize the automatic measurement of building surface radioactivity, a mobile robot equipped with highly sensitive surface detectors has been developed; it can move automatically based on route plans to measure radioactivity on concrete floors and walls. In the development of this system, efforts were especially made to realize accurate robot motions by applying self-position identification system in consideration of the fact that the measurement should cover all the surfaces of planned areas with minimum overlap.

JAEA Reports

Development of building surfaces contamination measurement technique (Contract research)

Hatakeyama, Mutsuo; Ito, Hirokuni; Yanagihara, Satoshi

JAERI-Tech 2000-056, 38 Pages, 2000/09

JAERI-Tech-2000-056.pdf:5.23MB

no abstracts in English

Journal Articles

Evaluation of methodology on radioactive inventory estimation in the Japan power demonstration reactor decommissioning program

Sukegawa, Takenori; Hatakeyama, Mutsuo; Yanagihara, Satoshi

Journal of Nuclear Science and Technology, 37(Suppl.1), p.367 - 371, 2000/03

no abstracts in English

Journal Articles

Procedure for segregation of non-radioactive waste related to decommissioning nuclear facilities; Experiences on the Japan Power Demonstration Reactor dismantling

Tachibana, Mitsuo; Hatakeyama, Mutsuo; Yanagihara, Satoshi

Nihon Genshiryoku Gakkai-Shi, 41(6), p.677 - 685, 1999/00

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Decontamination and radioactivity measurement on building surfaces related to dismantling of Japan Power Demonstration Reactor (JPDR) (contract research)

Hatakeyama, Mutsuo; Tachibana, Mitsuo; Yanagihara, Satoshi

JAERI-Tech 97-064, 43 Pages, 1997/12

JAERI-Tech-97-064.pdf:2.04MB

no abstracts in English

Journal Articles

Demonstrating decontamination at JPDR

Tachibana, Mitsuo; Hatakeyama, Mutsuo

Nucl. Eng. Int., 41(502), p.39 - 40, 1996/05

no abstracts in English

Journal Articles

Dismantling of Japan Power Demonstration Reactor; Decontamination and final radiological survey of buildings

Hatakeyama, Mutsuo; Tachibana, Mitsuo

Doryoku, Enerugi Gijutsu No Saizensen : Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu 1996, 0, p.360 - 363, 1996/00

no abstracts in English

Journal Articles

Results and outline of JPDR dismantling demonstration project

Miyasaka, Yasuhiko; ; Tanaka, Mitsugu; Nakamura, Hisashi; ; Tachibana, Mitsuo; ; Hatakeyama, Mutsuo; ; Yoshimori, Michiro; et al.

Nihon Genshiryoku Gakkai-Shi, 38(7), p.553 - 576, 1996/00

no abstracts in English

Journal Articles

The Japan power demonstration reactor decommissioning program; Decontamination and radioactivity measurement on building surfaces

Tachibana, Mitsuo; Hatakeyama, Mutsuo; ; Yanagihara, Satoshi

ICEM 95:Proc. of 5th Int. Conf. on Radioactive Waste management and environmental Remediation,Vol. 2, 0, p.1683 - 1686, 1995/00

no abstracts in English

Journal Articles

Decontamination on concrete surfaces in decommissioning of the Japan Power Demonstration Reactor

Tachibana, Mitsuo; ; Myodo, Masato; Hatakeyama, Mutsuo;

The 3rd JSME/ASME Joint Int. Conf. on Nuclear Engineering (ICONE),Vol. 4, 0, p.1811 - 1815, 1995/00

no abstracts in English

Journal Articles

Evaluation of radioactive inventory in JPDR due to neutron activation

Sukegawa, Takenori; Hatakeyama, Mutsuo

Dekomisshoningu Giho, (8), p.66 - 77, 1993/06

no abstracts in English

Journal Articles

Telescopic measuring method for specific activities of structural components in reactor pressure vessel

Katagiri, Masaki; Hatakeyama, Mutsuo; ; Ito, Hirokuni;

Journal of Nuclear Science and Technology, 29(8), p.735 - 744, 1992/08

no abstracts in English

JAEA Reports

Determination of the long-lived nuclides in biological shielding concrete, ion exchange resine and fuel storage pool water of JPDR

Takeishi, Hideyo; ; ; Kono, Nobuaki; ; Yonezawa, Chushiro; Hatakeyama, Mutsuo;

JAERI-M 89-224, 45 Pages, 1990/01

JAERI-M-89-224.pdf:1.13MB

no abstracts in English

Journal Articles

Evaluation of contamination on concrete of JPDR building

Yasunaka, Hideo; Hatakeyama, Mutsuo; Sukegawa, Takenori; Kozaki, Tamotsu; ; Hoshi, Tatsuo

Proc. of the 1989 Joint Int. Waste Management Conf., Vol. 1, p.183 - 187, 1989/10

no abstracts in English

Journal Articles

Microwave irradiation technology for contaminated concrete surface removal

Yasunaka, Hideo; ; ; ; ; Hatakeyama, Mutsuo; ; Tachikawa, Enzo

Proc. 2nd Int. RILEM Symp. on Demolition Method and Practice, p.280 - 289, 1988/00

no abstracts in English

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